ALBERT

Notes: Azimines. IITeil I, siehe [1]. . Preparation and Thermal Fragmentation of cis- and trans-2,3-Diphenyl-1-phthalimido-2,3-di[15N]-azimine Teilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft am 8./9. Oktober 1976 in Genf und als Autoreferat veröffentlicht [2].cis- and trans-2,3-Diphenyl-1-phthalimido-2,3-di[15N]-azimine (11 and 12) wer synthesized from cis-di[15N]-azobenzene (10) and phthalimido-nitrene (2), the latter generated by lead tetraacetate oxidation of N-aminophthalimide (1). Useful information was obtained from the comparison of several data of 11 and 12 with those of the unmarked diphenyl-azimines 5 and 6 (R = C6H5).The 15N- and 13C-NMR. spectra of 11 and 12 were interpreted to furnish additional evidence for the azimine structure and for the indicated configurations. The IR. spectra permitted identification of two bands in the 1200 to 1450 cm-1 region, probably characteristic for the functionality of diaryl-phthalimido-azimines. Comparison of the mass spectrum of 11/12 with that of the unmarked analogues 5/6 (R = C6H5) permitted the interpretation of the fragmentation path of 1-phthalimidoazimines. The major path may be the purely thermal decomposition to 13 and 7 (R = C6H5), respectively. Two other competing fragmentation paths are discussed.Prolonged thermolysis of 11 at 61° in solution gave 83% of N,N′-diphenyl-N N′-phthaloyl-di[15N]-hydrazine (13) of 98% isotope purity, which means that the imide nitrogen atom and N(1) of the azimine function are removed in this reaction. A mechanism passing through an intermediate cyclic tetrazene 16 is considered.Benzocyclobutenedione (14) added to trans-azobenzene (4, R = C6H5) under the influence of a high pressure lamp in a quarz apparatus to give N,N′-diphenyl-N,N′-phthaloyl-hydrazine (7, R = C6H5). This reaction was found not to take place in the dark, even after prolonged heating in trichloromethane.

Notes: Azimines. I. Synthesis and Stereoisomerism of 2, 3-Diaryl- and 2, 3-Dialkyl-1-phthalimido-aziminesTeilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in Lausanne am 7./8. Mai 1971 und als Autoreferat veröffentlicht [1].Special examples of a new class of compounds, the open-chain azimines (1), have been prepared and their properties examined.Addition of phthalimido-nitrene (4), generated by lead tetraacetate oxidation of N-aminophthalimide (3), to cis- and trans-azobenzene (6 and 5), -azo-p-toluene (8 and 7), and to trans-azomethane (9), -azoethane (10) and -azo-α-phenylethane (11) afforded the separable cis- and trans-isomers of 2, 3-diphenyl- (12 and 13), 2, 3-di-p-toyl- (14 and 15), 2, 3-dimethyl- (16 and 17), 2, 3-diethyl- (18 and 19) and 2, 3-di-(α-phenylethyl)-1-phthalimido-azimines (20 and 21) in different ratios (see Scheme 1).The constitution of the nitrene azo compound adducts as azimines was derived from their properties, especially from the conjugation effect (visible in the UV. spectra) of the aryl-substituted compounds and from the non-equivalence (shown by the 1H-NMR. spectra) of the substituents on the two nitrogen atoms derived from the azo compounds. This evidence excluded the triaziridine 22 and an alternative azimine constitution 23 for the adducts.Of the two stereoisomers obtained for each of the azimines, the aryl-substituted examples 12/13 and 14/15 were readily interconverted by warming in solution, the cis-isomers 12 and 14 exceeding the trans-isomers 13 and 15 in the equilibrium. The dialkyl-azimines appear to be configurationally more stable, since interconversion of the dimethyl-azimines 16 and 17 was not possible under the same conditions, and also not before another thermal reaction took place (see below).The identification of the N(2)-N(3) bond as the stereogenic center, i.e. that the stereoisomerism of the azimines is due to the difference in relative position at N(2) and N(3) of the substituents derived from the azo compounds, as well as a configurational assignment was possible in the aryl-substituted examples on the basis of the UV. spectroscopic comparison of the isomeric azimines with the corresponding stereoisomeric azoxy compounds: The cis-azimines 12 and 14 showed absorptions similar to those of cis-azoxybenzene and cis-azoxy-p-toluene, and the trans-azimines 13 and 15 showed absorptions similar to those of the respective trans-azoxy compounds. With respect to the configuration of the alkyl-substituted azimines, it was observed that the isomers 17 and 19, which from their formation and chromatographic behaviour are likely to be the trans-isomers, show a visible coupling (∽ 1 Hz) between the two H (α)'s in the 1H-NMR. spectrum, whereas the dimethyl isomer 16 (cis) does not exhibit such a coupling.Thermal treatment of four azimines, namely 12, 14, 16 and 17, in solution for a longer time afforded the corresponding N, N′-disubstituted N, N′-phthaloyl-hydrazines 27, 28 and 29. The order of velocity of this fragmentation with nitrogen extrusion was 12/13 ≍ 14/15 〉 16(cis) 〉 17(trans).

Notes: The 6-chloro-2-cyclohexenones 3, 6 and 11, and the 5-chloro-2-cyclopentenone 15 were newly synthesized. The results obtained with compounds 3 and 15 in photocycloadditions to olefins show that the oxetane vs. cyclobutane product ratio is reduced by the substitution of florine by chlorine in the α′ -position of the enone. No oxetanes are formed in the intramolecular photocycloaddition of 6. Compound 11 does not photoadd to olefins. The newly synthesized 2-chloro-3-cyclohexenones 8 and 9 are also photostable towards light of λ=366 nm, but π-π*-excitation (λ=254 nm) in pentane leads to the formation of 4,4-dimethylcyclohexanone (29).

Notes: Polynuclear Cobalt Complexes. II. Preparation and Structure of [(tren) (NH3)Co(O2)Co(NH3) (tren)](SCN)4 · 2H2OThe title compound is obtained on oxygenation of [Co(tren)(H2O)2]2+ in 6M aqueous ammonia or by ligand exchange starting from [(NH3)5Co(O2)Co(NH3)5]-(NO3)4. An X-ray structure determination was made. The substance forms monoclinic crystals, space group P21/c, lattice constants a=10,135, b=8,473, c=19,484 Å, β=108,58°, with two formula units in the cell. The final R is 0,066. The binuclear cation has a center of symmetry, so the Co—O—O—Co unit is planar; the Co—O—O angle is 111,5°. The tertiary nitrogen atoms of both chelate groups are cis to the O2 bridge, as found in doubly bridged [(tren)Co(O2,OH)Co(tren)](ClO4)3 · 3H2O.On acidification in solution, the singly bridged cation [(tren) (NH3)CoO2Co(NH3)(tren)]4+ (a) loses the bound O2 completely. But unlike the doubly bridged cation b, the rate of dissociation of a is independent of pH (Fig. 5). At higher pH (8-10) bridging a→b (Fig. 2) occurs. Both reactions must have the same rate determining step, the first order rate constants being of the order of 2 · 10-3 s-1 (25°, 0,35M KCl).

Notes: Following the intraperitoneal administration of high doses of 14C- and 3H- labelled retinoic acid (1) to rats, three major metabolites and the intact compound were isolated from the feces in microgram amounts by use of column, thin-layer and high-pressure liquid chromatography. Their structures were elucidated by mass spectrometry and Fourier Transform 1H-NMR. spectroscopy as 2 (all-trans-4-oxoretinoic acid), 3 (7-trans-9-cis-11-trans-13-trans-5′-hydroxy-retinoic acid).Hydroxylation of the 5-methyl group of the cyclohexene ring, oxidation of the cyclohexene ring in position 4 and cis-trans isomerisation of the nonatetraenoic acid side chain were the reactions, which produced these products from retinoic acid. The metabolites 2 and 4 each accounted for about 4% of the radioactivity administered. The metabolite 3 and the parent compound accounted for about 16% and 17% of the dose, respectively.

Notes: Novel types of acetylenic sugarsThe coupling, following Cadiot's procedure, of a 6-bromo-5,6-dideoxy-1,2-O-isopropylidène-3-O-methyl-α-D-xylo-hex-5-yno-1, 4-furanose (1) with phenylacetylene, 2-propyn-1-ol or terminal acetylenic sugars gave with excellent yields the expected diynes (an enediyne when the terminal acetylene was the 3,5, 6-trideoxy-1,2-O-isopropylidene-α-D-glycero-hex-3-en-5-yno-1,4-furanose 7). The chloro analogue 8 of 1 on treatment with lithium thiophenate gave the corresponding phenylthio-acetylenic sugar 9. An acetylene was also formed by reacting the gem-difluoro-olefinic sugar 10 with butyllithium whereas the same olefinic sugar and its 3-O-benzyl analogue 11 gave only a gem-fluoro-arylthio-olefinic sugar (13-15) as a mixture of the Z and E isomers (Z/E 〉 4) when treated with the conjugate base of an arylmercaptan.

Notes: Some more examples of stable free radicals of carbohydrate heterocyclic derivatives2-Glycosyl-4,4,5,5-tetramethylimidazoline- 3-oxide-1-oxyls and 2-glycosyl-4,4,5,5-tetramethylimidazoline 1-oxyls have been prepared in nine carbohydrate series, which proves the generality of the method. The hyperfine coupling constant between the free electron and the α-proton of the glycosyl group is never very large (0-2.3 G) but a correlation between its value and the structure of the aglycone has been noted. Free radicals of that type, stable in aqueous solutions, are potentially interesting for biological studies.

Notes: Interpretation of the chemical and spectral (IR., UV., 1H- and 13C-NMR.) properties of the antitumor antibiotic hedamycin (C41H50N2O11) suggests that the molecule contains a methyl substituted 1-hydroxyanthraquinone nucleus, an α, β-unsaturated ketone, two sugar-like tetrahydropyran rings (4 and 8) and an aliphatic chain 2, presumably with an epoxy group (see the Scheme).

Notes: Halogenated pyridines and 1,8-naphthyridines. VI.The principle of the synthesis of 3-halomethyl-2,6-dichloro-pyridines has been extended to compounds with side chains of more than one carbon atom in the 3-position. Feasible synthetic routes are outlined starting from cheap, commercially available α-methylideneglutaronitrile and trichloroalkyl functional compounds which yield the intermediate 1,3,5-trisubstituted alkanes. These are cyclized by aqueous mineral acid or by hydrogen bromide in an organic solvent to 2-substituted glutarimids or hexahydronaphthyridinones, depending on the mode of cyclization. The final aromatization provides a simple route to pyridines or 1, 8-naphthyridines.

Notes: Proton catalysed [1,2]-H-shift in the rearrangement of 6,7-diphenyl-5,6-dihydropterine (I) to 6,7-diphenyl-7,8-dihydropterine (III)The arrangement from I to the thermodynamically more stable III undergoes through a acid catalysed [1,2]-H-shift (intramolecular 6,7-hydride rearrangement) (see Scheme 1).

Notes: New Routes to 1H- and 2H-PyrrolesA synthesis of 1H-pyrroles is described starting with pyridine analogues of chalcones and involving the reaction of acetic anhydride with 1-pyrroline-1-oxides. Another route leads from 1-pyrrolines to 2 H-pyrroles via bromination with N-bromosuccinimide and subsequent dehydrobromination in dimethylformamide.

Notes: The title compound 1 is a further example of an olefinic alcohol that undergoes ether formation under basic conditions (→ 3) although the double bond is not activated by an electron-attracting group. This unusual reactivity is due to steric compression, which is increased in the 10-methyl analogue 2. This forms the corresponding ether 7 at a much higher rate. - In a deuteriated medium, base-catalysed cyclization of 1 gives the exo-deuteriated ether 6, corresponding to trans-addition. - An X-ray structure analysis of 4, the p-nitrobenzoate of 1, is presented.

Notes: Reaktionen von 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]octan-2,6-diolen und deren 4,4,8,8-Tetrachlor- und 4,8-Dichlorderivaten mit DiphosphortetrajodidEs wurden die P2I4-Reaktionen mit 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]-octan-2,6-diolen (3/6), mit dem 4,8-Dichlorderivat 4 und mit den 4,4,8,8-Tetrachlorderivaten 5/7 untersucht. Dabei entstanden die Styrolderivate 9 und 12, die anti-Bishomobenzolderivate 8 und 11, ein Homotropylidenderivat 10, ein Cyclo-octatetraenderivat 13 und ein 9-Oxabicyclo[4.2.1]nona-2,4,7-trienderivat 15. Die Ausbeuten lagen zwischen 1 und 10%. Die Bildung aller dieser Produkte liess sich unter der Annahme der primären Umwandlung einer oder beider Hydroxylgruppen in Abgangsgruppen X oder X und Y (wahrscheinlich X=Y=I) mechanistisch deuten. Die Reaktion der Deschlorderivate 3/6 lieferte nach Substitution beider Hydroxyl-gruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 9 (Schema 2) und (b) unter Abspaltung von XY das Homotropylidenderivat 10 (Schema 3a) und das Bishomobenzolderivat 8 (Schema 3b). Die Reaktion des 4,8-Dichlor-derivates 4 lieferte nach Substitution beider Hydroxylgruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 12 (Schema 2), und (b) unter Abspaltung von XY das Bishomobenzolderivat 11 (Schema 3b). Die Reaktion mit den 4,4,8,8-Tetrachlorderivaten 5/7 lieferte: (a) nach Substitution beider Hydroxyl-gruppen durch X und Y unter Abspaltung von XCl und YCl das Cyclooctatetraen-derivat 13 (Schema 4), und (b) nach Substitution nur einer Hydroxylgruppe durch X unter Abspaltung von XCl und HCl das bicyclische Derivat 15 (Schema 5). Alle diese Reaktionen sind zusätzlich zu den angegebenen Fragmentierungen und Eliminierungen noch teilweise von Umlagerungen des Kohlenstoffgerüstes begleitet.Die thermische Umlagerung von 1,5-Dichlor-2,4,6,8-tetramethyl-cycloocta-1,3,5,7-tetraen (13) in das Styrolderivat 12 wurde in Abhängigkeit der Lösungs-mittelpolarität untersucht und mit der analogen thermischen Umlagerung von Brom-cyclooctatetraen und Chlor-cyclooctatetraen verglichen.

Notes: Leaf-gland Pigments: Coleons S and T from Plectranthus caninus ROTH (Labiatae), New Hydroquinones of the Abietane Series with a Diosphenol/trans-A/B-6,7-Diketone Structure.Coleons S and T were isolated from the more polar fractions from extracts of the above mentioned plant. Coleon S, C20H26O6, has been shown to have structure 1a, and coleon T, C20H26O6, structure 2.

Notes: On a Synthesis of the angular Di(cyclobuteno)benzolIn the course of our studies aimed at better understanding the Mills-Nixon effect, we have also prepared the angular di(cyclobuteno)benzene (1), the synthesis of which has been recently described by another group [3]. Our completely different and essentially simpler synthetic approach will be pointed out. A special pyrolysis apparatus is designed.

Notes: A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A. The efficient preparation of α- and β-cyclocitral by the novel process is also described.

Notes: Six iridoid glucosides have been isolated from Globularia cordifolia by the combination of open column - and high performance liquid chromatography. The structure of the new compound, named globularifolin, and the identity of the others have been established by chemical transformations and spectral evidence of the compounds and their derivatives.

Notes: The interaction of selected tetramethylpiperidine derivatives with radicals arising from the Norrish-type I cleavage of dibenzyl ketone under oxygen was studied. Product analyses and kinetic studies showed that the investigated sterically hindered piperidine derivatives have a pronounced effect on both the nature and distribution of the products of photolysis of dibenzyl ketone in the presence of oxygen. Observations indicated that the phenylperacetoxyl radical is formed as an intermediate during irradiation and that it interacts with the additives used. Possible mechanisms of the reactions studied are discussed.The observation that oxidation of an isolated double bond by the radicals formed in dibenzyl ketone photolysis under oxygen is strongly inhibited in the presence of the studied sterically hindered amines is discussed in the light of the results presented. The findings are considered in relation to the problem of polymer stabilization.

Notes: Several attempts to prepare 3-acetyl-5-benzyl-3-pyrrolin-2-one (7) from phenylalanine are described. This goal was only reached formally, because compound 7 exists in the tautomeric form of (Z)-5-benzyl-3-(1′-hydroxyethylidene)-4-pyrrolin-2-one (17) according to the spectral data. The problem of tautomerism in pyrrolinone systems is discussed.

Notes: Nucleophilic Aminoalkylation with ThiopivalamidesVorläufige Mitt. [1].Of the twelve thioamides 7a-e and 8a-g, only N,N-dimethylthiopivalamide (7a) could be metallated at the CH-group in a-position to the N-Atom. The reagent 9 thus obtained (Table 1) reacts in high yields with primary haloalkanes, with aldehydes, and with non-enolizable ketones (Table 2). As shown in Scheme 1, the products can be hydrolyzed to pivalamides, cleaved to secondary amines, or reduced to neopentylamines (see 18/19, 15/equation (4) and (5), and 16/20, respectively).

Notes: Excitation spectra of the cations of pentafluorophenol, 2,3,4-trifluorophenol, 2,4,5-trifluorophenol, 2,5-difluorophenol and 3,5-difluorophenol have been obtained by pumping the B̃2 A″ ← X̃2A″ transition with a dye laser. The cations were first produced in their ground states by Penning ionisation using argon metastables. Vibrational frequencies of some of the fundamentals have been inferred for these cations in the B̃2 A″ state from the excitation spectra, and in the X̃2 A″ state from the emission spectra. Possible applications of the reported results are suggested.

Notes: Synthesis of Polyhalogenated Butyryl Chlorides, Precursors of Pyrethroid HaloketenesThe copper (I)-catalyzed free radical addition of halomethanes to acrylates and the addition of halogenated acetic acid derivatives to fluoro- or chloro-substituted ethylenes affords polyhalogenated butyric acid derivatives. Chlorides of these acids serve as precursors for haloketenes used in efficient syntheses of pyrethroids.

Notes: The pyrrolidines 2 and 10 were obtained by thermal ene-reactions at +70° and +180° from the (Z)-4-aza-1, 6-diene 1 and from the (E)-4-aza-1, 6-diene 9 in the ratios of 75:25 and 50:50, respectively. On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at - 78° and - 35° giving in high yield the trans-pyrrolidine 2 from 1 with 100% and from 9 with 89% diastereoselectivity.

Notes: Low Temperature 13C-NMR. Spectra of 13C- and 6Li-Labelled Chloro-, Bromo-, and Iodo-lithiumcarbenoidsThe 13C-NMR. spectra of tetrahydrofuran solutions of 16 chloro-, bromo-, and iodo-6lithio- and -7lithio-carbenoids with 13C-labelled methane, ethane, ethylene, and cyclopropane C-skeletons have been measured at temperatures around - 100° (for examples see Fig. 1 and 2). Invariably, the exchange of hydrogen or halogen by lithium causes deshielding (Δδ, see Table 1) of the 13C-signal by up to 289 and 434 ppm, respectively, and decrease of 1J (1H, 13C) and 1J(13C,13C) couplings (see Table 2) with the C-atom of up to 104 and 30 Hz, respectively. The 1J(6Li, 13C) and 1J(7Li, 13C) coupling of ca. 17 and 45 Hz, respectively, obtained in ten cases (Table 1) is independant of the substitution pattern of the C-skeleton and of the particular halogen atom.

Notes: 1H- and 13C-NMR. data are reported for the complexes [Pt(1)L] and [Pt(2)L]; 1 = OC6H4CH = NCH2CH2O, 2 = OC6H4CH = NC6H4O; L = PR3, AsR3, C ≡ N (cyclohexyl), DMSO, pyridine, secondary amine. The molecular structures of [Pt (2) (NHEt2)] (I) and [Pt (2) (PPh3)] (II) have been determined by X-ray analysis. Relevant bond distances for I: Pt-N (amine) = 2.076 Å, Pt-N (imine) = 2.017 Å, Pt-O = 1.992 Å and 2.002 Å; for II: Pt-P = 2.248 Å, Pt-N = 2.064 Å, Pt-O = 1.964 and 2.005 Å. Both the solid and solution state data are interpreted in terms of differences in the trans influence of the ligand L. The question of metal-ligand d-p π back bonding to the imine is discussed.

Notes: The complexation of primary ammonium salt substrates by macrocyclic polyether receptor molecules provides a general method for studying the nature and stereochemistry of intermolecular interactions. The substrates and receptors are fitted each with one of the interacting units and the resulting effects in the complex are analyzed. The method is used to study the biologically important indole-pyridinium donor-acceptor interaction. The complexes between macrocycles, bearing an indole group in side chains, and pyridinium-ammonium salts display a characteristic charge-transfer band. The absorption coefficients and stability constants have been determined. Competition experiments also provide a new method for measuring the stability constants of macrocycle-ammonium complexes in organic solvents.

Notes: Aristoserratine, a New Indole Alkaloid from Aristotelia serrata W.R.B. OLIVER and from A. peduncularis (LABILL.) HOOK. F.The new indole alkaloid aristoserratine (2) has been isolated from Aristotelia. Its structure and absolute configuration were elucidated on the basis of spectroscopic data.

Notes: When the Hammett-Taft equation log (k/ko)=ρq · σ1q is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with σ1q except in cases where R exerts an anchimeric effect. The reaction constant ρq for 6 is - 0.12 and is typical for a nucleophilic solvent-assisted ks process at a primary C-atom. The tertiary halides 1 and 3, however, which react with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively. The reaction constant pq is therefore a sensitive gauge for charge development in the transition state for solvolysis of saturated compounds.

Notes: Reactions of Some 3-Deoxy-3-trifluoroacetamido-D-ribofuranosyl Halides with Mercuric CyanideThe expected 2,5-anhydro-D-allononitrile 11 was obtained when the 2-O-benzoyl-3-deoxy-3-trifluoroacetamido-D-ribofuranosyl bromide reacted with mercuric cyanide, whereas the isomeric 1,2-O (1-cyanoethylidene) derivative was formed from the 2-O-acetylated halide; no reaction occurred when the halide was 2-O-p-nitrobenzoylated.

Notes: A series of electrically neutral lipophilic di-, tri-, and tetra-amides containing tertiary-amine N-atoms were prepared in order to investigate their selectivity for alkali and alkaline earth metal cations in solvent polymeric membranes. Considerable selectivity changes were observed for membranes incorporating certain of these ligands as compared with ligand-free membranes. A 1:1 cation/ligand complex was isolated from N, N′, N″-triheptyl-N, N′, N″-trimethyl-nitrilotriacetamid and Mg (SCN)2 whereas with Ca (SCN)2 the corresponding 2:3 cation/ligand complex was formed. N, N′, N″, N‴, N‴-tetramethyl-ethylenediaminetetraacetamide yields a 1:1 cation/ligand complex with Mg (SCN)2.

Notes: Contribution to the Mass Spectral retro-Diels-Alder Reaction: 1,2,3,4-Tetrahydrophenanthrene[1,4-13C]-1,2,3,4-Tetrahydrophenanthrene (1) was synthesized starting from [1,4-13C]-succinic acid. The mass spectral behavior (EI./MS., 70eV) of 1 is very similar to that of tetraline [2] concerning its loss of ethylene from the molecular ion. Similarly the fragmentation reaction of the synthetic precursors, ketones 7 and 8, seems to partly undergo a carbon rearrangement reaction prior to the elimination of ethylene which is unlike to the behavior of α-tetralone.

Notes: Contributions to the Knowledge of the Corrin Chromophore, X. Reaction of Derivatives of Cobyrinic Acid Heptamethyl Ester with Hypochlorous Acid(Cobalt)-dicyano-, chloro-cyano-, and dichloro-cobyrinic acid heptamethylesters (1, 2 and 3), respectively, as well as their 10-chloro derivatives 4, 5 and 6 react with hypochlorous acid. A report on the structure and some properties of the reaction products 8, 9 and 10 is given.

Notes: 3β, 19-Epoxy-3 α-methoxy-steroids (e.g. 1, Scheme 1) are converted into the corresponding 3 α-methoxy-19-oxo compounds (e.g. 3) in the presence of boron trifluoride etherate, via an intramolecular hydride ion transfer from C (19) to (3) which is shown to be an equilibrium process. By subjecting the specifically deuteriated (19 S)- and (19 R)-compounds 1b and 1c to this reaction it was shown to be highly stereoselective.

Notes: Chemically and isotopically pure Al35Cl3 and Al37Cl3 are synthesized from Al (s) and HCl (g). The yield is quantitative and no measurable decrease in isotopic content from HCl to AlCl3 takes place.

Notes: The UV. irradiation of 17 β-acetoxy-4-oxa-5 α-androst-1-en-3-one (1) yields A,B-diseco-steroids originating from a Norrish I process of the lactone function.

Notes: Structural Dynamics of Pentadienyl Metal-Compounds Bearing a Terminal Alkyl Substituent: Both ‘Stereoselective’ and ‘Stereodefensive’ Synthesis of a Natural Perfume.The (2Z, 4E)-, (2E, 4Z)- and (2E, 4E)-isomers of 2,4-decadien-1-ol (5) have been obtained with high and predictable stereochemical homogeneity starting from both (Z)- and (E)-1, 4-decadiene. These hydrocarbons were hydroxylated in a reaction sequence consisting of metallation (by means of s-butyllithium or butyllithium/potassium-t-butoxide, giving rise to organometallic intermediates of specific conformation), dimethoxyborylation and oxidation. The different decadienols as well as (2E, 4Z)-2, 4-undecadien-1-ol were converted into the isovalerates, the ester derived from (2E, 4Z)-2, 4-decadien-1-ol being a natural flavor component.

Notes: Chemical transformation of tricyclo [3.3.0.02,8]octan-3-one (1) have been carried out in order to explore its potential utility as a versatile synthon for polycyclopentanoid terpenes and prostacyclin analogs. Various functionalizations of rings A and B and annulation of a third ring C were achieved in generally high yields. The system provides for a large measure of regio- and stereoselective reaction control.

Notes: Replacement of lithium or magnesium by titanium can furnish nucleophilic organometallic reagents of high selectivity as exemplified by the title compound 1 (see Tables 1-3).

Notes: Nucleosides and Nucleotide. Part 15. Synthesis of Deoxyribonucleoside Monophosphates and Triphosphates with 2(1H)-Pyrimidinone, 2(1H)-Pyridinone and 4-Amino-2(1H)-pyridinone as the BasesThe phosphorylation of the modified nucleosides 1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyrimidinone (Md, 4), 4-amino-1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyridinone (Zd, 6) and the synthesis of 1-2′-deoxy-β-D-ribofuranosyl-2(1 H)-pyrimidinone-5′-O-triphosphate (pppMd, 1), 1-(2′-deoxy-β-Dribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppIId, 2), and 4-amino-1-(2′-deoxy-βD-ribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppZd, 3) are described. The nucleoside-5′-monophosphates pMd (5) and pZd (7) were obtained by selective phosphorylation of Md (4) and Zd (6), respectively, using phosphorylchloride in triethyl phosphate or in acetonitril. The reaction of pMd (5) pII d (8) or pZd (7) with morpholine in the presence of DCC led to the phosphoric amides 9, 10 and 11, respectively, which were converted with tributylammonium pyrophosphate in dried dimethylsulfoxide to the nucleoside-5′triphosphates 1, 2 and 3, respectively.

Notes: Two novel cannabinoid model compounds, (3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (22) and 4″(R, S)-methyl-(3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (23) were synthesized by acid-catalyzed condensation of (+)-trans-p-mentha-2, 8-dien-l-ol (1) with the substituted resorcinols 18 and 19 obtained by a Wittig reaction between 3, 5-bis(benzyloxy)benzaldehyde (7) and methyl 4-bromobutanoate (10) or methyl 4-bromo-2(R, S)-methylbutanoate (11) resp. with subsequent hydrogenation. The resulting methyl esters 20 and 21 were hydrolyzed to give acids 22 and 23.

Notes: In HSO3F/SO2ClF the β-hydroxy esters Ph-CHOH-CMe2-COOR (1, R=Me, Et) are doubly protonated, then transformed into the fluorosulfates 7 and (partly) into the fluorides 8. At -15°, both 7 and 8 undergo a rearrangement, forming derivatives of Me2C=C(Ph)COOR (2). By labelling 1 with 13C, singly (13C(3)) and doubly (13C(1,3)), it could be shown that exclusively the ROOC groups undergo a 1,2-shift. Compound 2 is also formed in HSO3F/SO2ClF from the isomeric Me2COH-CHPh-COOR (3) by elimination, and less easily from the α-hydroxy ester Ph-CMe2-CHOH-COOR (5) via a phenyl 1,2-shift. Another isomer, Ph-C(OH)Me-CHMe-COOR (4) gives products different from 2.Using more acidic systems containing SbF5, the free carbenium ions 13 (Ph-CH+-CMe2-COOR) can be stabilized; they do not form 2, possibly because of complexation of the ester group with SbF5. The energy profile and the mechanism of the rearrangement 1 → 2 are discussed.

Notes: It is shown that ligand 1, designed to span trans-positions, under appropriate conditions also gives cis-mononuclear complexes of platinum (II). The structure of cis-[PtCl2 (1)] (2) has been determined by single-crystal X-ray diffraction. The major distortion from square planar coordination is the P-Pt-P angle of 104.8°. Values of valence angles within the bidentate ligand indicate that this part of the molecule is very strained. Two phenyl groups, one on each phosphorus, lie almost parallel to each other separated by ca. 3.2-3.3 Å. The 1H-NMR. data for this compound show that the π-phenyl interactions observed in the solid state occur also in solution. The preparation and NMR.-spectroscopic properties of trans- and cis-[PtH(PPh3) (1)] [BF4] are reported.

Notes: A Convenient Synthesis of LeucovorinThe synthesis of leucovorin, a 5-formyl-(6R or S)-5,6,7,8-tetrahydropteroyl-L-glutamic acid (II) is described. The L-folic acid was first reduced to (6R, S)-tetrahy-dro-L-folic acid (I); formylation with methyl-formate in DMSO gave directly leucovorin (as a diastereomeric mixture) in good yields. To demonstrate, that the formylation occurred regiospecifically at N (5) and not at N (10), N (10)-nitroso-(6 R, S)-tetrahydro-L-folic acid was formylated under the same conditions. Reductive elimination of the N (10)-nitrosogroup gave the identical leucovorin as in the previous case. The synthetic leucovorin was biologically as active as the natural product with Streptococcus faecalis ATCC 8043 and Pediococcus cerevisiae ATCC 8081.

Notes: Photochemical reactions of norbornadiene with substituted acetylenes in the presence of Fe(CO)5 gave various products of different types, depending on the nature of the acetylene. The results are summarized in Table 1. The cyclopentanone 1 was always formed in these reactions. In the reaction of disubstituted acetylenes such as dimethyl acetylenedicarboxylate and ethyl phenylpropiolate, the cyclopentenones 2 and 5 were formed, respectively. By contrast, propiolic esters produced the cyclohexenones 3 and 4, in which the ester group was attached on the β carbon with respect to the keto group. Plausible mechanisms for the formation of these products are shown in Schemes 7 and 8. The reaction of diphenylacetylene gave the cyclohexendione 7 as well as the cyclopentenone 6. Two enedione products 8 and 9 were obtained from the reaction of phenylacetylene. Compound 9 was converted to the aromatic diacetate 13 by heating with acetic anhydride in pyridine. On irradiation in the presence of Fe(CO)5 norbornene reacted similarly with dimethyl acetylenedicarboxylate and phenylacetylene to give the cyclopentenone 14 and the cyclohexenone 15, respectively. Compound 15, upon heating, isomerized to hydroquinone 16, which on acetylation gave the diacetate 17.

Notes: Partial Synthesis and Oncostatic Properties of Pseudotubulosines, Analogues of Emetine and TubulosinePseudotubulosines, structural analogues of emetine and tubulosine, have been synthesized by either Pictet-Spengler or Bischler-Napieralski condensation from dihydrocorynantheal or corynantheidal. Spectral data, cytotoxic and oncostatic properties of these new alkaloids are described.

Notes: It is shown that the ab initio STO-3G treatment applied to simple saturated linear, branched and cyclic hydrocarbons, assuming standard geometries, yields orbital energies ∊jSTO-3G for their canonical orbital ϕj which correlate perfectly with the observed C2s ionization energies Ijm, if Koopmans' approximation is accepted.Applying the Foster-Boys localization procedure to these canonical orbitals ϕj leads to localized orbitals λμ and their corresponding Hartree-Fock matrix Fλ = (Fλ,μv). An examination of the matrix elements Fλ,μv, i.e. of the self-energies Aμ = Fλ,μμ of the localized CC- and CH-orbitals λμ and of the cross terms Fλ, μv (μ ≠ v) between them, leads to the conclusion that a satisfactory approximation should be obtained by setting Aμ = A for all μ, Fλ,μv = B if λμ and λv are vicinal and neglecting all other cross terms. The resulting model is nothing but the well-known equivalent bond orbital model of Lennard-Jones & Hall, which however can now be calibrated using the known C2s-ionization energies of hydrocarbons. Due to the discrete structure and the wider range (∽ 8 eV) of the C2s band systems in the photoelectron spectra of these molecules this leads to a more satisfactory parametrization than using the narrower and badly resolved C2p band system.Comparison of calculated band positions using the calibrated model with observed C2s-band ionization energies for a series of hydrocarbons reveals that the simple equivalent bond orbital model is better than one might have expected.

Notes: Metabolites of Microorganisms. FerrithiocinThe strain Tü 1998 from Streptomyces antibioticus produces besides the indicator antibiotics β- and γ-rubromycins a new sulfur containing metabolite. This metabolite, called ferrithiocin, has been isolated in the form of a iron complex. The structure 1 of the iron-free compound was elucidated by spectroscopic studies and chemical degradation.

Notes: The Metabolism of the Retinoid Ro 10-9359. Isolation and Identification of the Major Metabolites in Human Plasma, Urine and Feces Synthesis of Three Urinary MetabolitesAfter oral administration of therapeutic doses of the 3H-labelled aromatic retinoic acid analog (retinoid) Ro 10-9359 (ethyl all-trans-9-(4-methoxy-2,3,6-trimethyl-phenyl)-3,7-dimethyl-2,4,6,8-nonatetraenoate) to humans 75 and 15% of the 3H-dose were excreted within the first five days in the feces and the urine, respectively. Using chromatographic procedures including high pressure liquid chromatography 18 metabolites could be isolated from human urine. Their structures were elucidated by mass spectrometry and FT-1H-NMR. spectroscopy. In these urinary metabolites the tetraene side chain of the parent compound Ro 10-9359 is shortened. The radioactivity of the identified urinary metabolites accounted for about 11% of the dose. Three urinary metabolites were synthesized. The main part of the radioactivity excreted within the first five days in the feces consisted of unchanged drug (60% of the dose). A smaller (amount 15% of the dose) could not be identified. The unchanged drug and a major metabolite, the corresponding acid, were found in human plasma.In an experiment with bile-duct cannulated rats the radioactively labelled retinoid Ro 10-9359 was injected intravenously. About 70% of the 3H-dose was excreted in the bile, within the first 48 hours. The whole radioactivity of the rat bile consisted of polar metabolites. No unchanged drug could be found. After enzymatic hydrolysis of the bile conjugates three metabolites were isolated. The main metabolite (49% of the i.v. dose) was a conjugate of the corresponding acid of the parent drug, already found as free compound in human plasma. The other bile metabolites (9 and 7% of the i.v. dose) had an intact side chain, too.An enterohepatic recycling of the bile metabolites was observed in the rat.

Notes: Stability in aqueous solution of some complexes of heavy metals with diaza-polyoxamacrocyclic ligandsStability of metal complexes (Mn+ = Cu2+, Ni2+, Co2+, Zn2+, Pb2+, Ag+ and Cd2+) with five diaza-polyoxamacrocycles (L = [2.1.1], [2.2.1], [2.2.2], [2.1] and [2.2] ) have been determined at 25°, in 0.1 M Et4N+ClO4- aqueous solutions, by means of potentiometric titrations. All cations form MLn+ complexes; Cu2+ also forms the MHL(n+1)+ protonated species with both [2.2.1] and [2.1.1] ligands. The stability of these complexes has been discussed in terms of structure and by considering the ionic radii of the cations together with the radii of the macrocyclic cavities. Different behaviour is observed between some of these complexes and the well known alkali and alkaline-earth cryptates, partly due to the more covalent nature of bonds formed by the investigated cations and the donor sites of the ligands. The effect of the substitution of two oxygen by two sulfur atoms in the pentadentate ligand [2.1] on the stability of the complexes is reported.

Notes: An arrangement for light induced vectorial charge separation is discussed in which the electron of the excited dye is transferred to an acceptor and the dye is recovered by electron tunneling through a high and narrow potential barrier. The possible relevance of the model in connection with photosynthesis is considered. Monolayers of Ru(II)-bipyridine complexes with long chain hydrocarbon substituents were investigated which may be useful as component in such arrangements.The surface pressure area isotherms of the monolayers were measured for various ionic compositions of the subphase, and the results demonstrate a strong effect of these ions on the structure of the layers. The layers were deposited on different substrates. The luminescence and its change by contacting the sample with water and by subsequent drying were found to be strongly dependent on the architecture of the layer assembly. Attempts of a photochemical cleavage of water with these assemblies failed.The pH-dependence of the absorption and the luminescence of a Ru(II) bipyridine-dicarboxylic acid complex in solution is interpreted by assuming that the electron in the excited state is localized in one pyridine part of the substituted ligand, the conjugation with the second half of the bipyridine carboxylic acid being negligible. Monolayer assemblies for measuring the energy transfer from the ruthenium complex to an adequate energy acceptor and from an adequate energy donor to the ruthenium complex were investigated. The results demonstrate that the deactivation of the excited ruthenium complex occurs mainly by passing the luminescent state.Assemblies were investigated for measuring the electron transfer from the excited ruthenium complex to an appropriate electron acceptor positioned in the carboxylate portion at the same interface as the electron donor. With bipyridinium ions as acceptor the ruthenium complex luminescence is quenched at average distances between acceptor molecules of about 10 Å, while this distance is 30, 60 und 75 Å for different cyanine dyes used instead of the ruthenium complex. A correlation between this distance and the ionization energy in the excited state of the donor is observed.

Notes: Synthesis of nickel complexes with a porphine-type ligand systemIn the presence of nickel(II) salts the bicyclic vinylogous amidine 1 is dimerized to the diamagnetic (1-amino-10,20-diaza-octahydroporphinato)nickel(II) complex 3. The condensation proceeds through a paramagnetic octahedral nickel(II) complex 2. Starting from 3, the (hexadecamethyl-10,20-diaza-hexahydroporphin)nickel bis (tetrafluoroborate) 7 (a (hexaaza [16]annulene)nickel(II) complex) was prepared in two steps. This highly electrophilic compound adds methoxide ions in consecutive and reversible steps to form first the (1-methoxy-10,20-diaza-octahydroporphinato)nickel tetrafluoroborate 8 and then the [cis-1, 11-dimethoxy-decahydroporphinato (2-)]nickel 6. 6, 7 and 8 were fully characterized and interconverted by addition and elimination reactions.

Notes: Singlet oxygen, generated chemically or photogenetically, reacts with biadamantylidene to give the corresponding dioxetane and epoxide only. When methylene blue (MB) or meso-tetraphenylporphin (m-TPP) is used as sensitizer the normal reaction course occurs giving dioxetane as the preponderant product in 2-propanol, ethyl acetate, acetone, pinacolone, methylene chloride, chloroform, carbon tetrachloride and benzene, although in the last two solvents some 10-25% of epoxide is formed. When erythrosin and rose bengal (RB) are used, epoxide becomes the main product (70-95%). Epoxide does not derive from chemical reaction with the solvent. Pinacolone, for example, is not oxidized to t-butyl acetate.The rose bengal reaction involves both singlet oxygen and radicals, since diazabicyclooctane (DABCO) and di-t-butyl-p-cresol interfere with the oxidation. A mechanistic scheme is proposed in which sensitizer and oxygen combine to produce sensitizer radical cation and superoxide radical anion. Subsequently, hydroperoxy radical, deriving from superoxide, reacts with substrate to give epoxide and hydroxy radicals. The latter adds to substrate to give a new radical which captures triplet oxygen. Epoxide is formed by loss of hydroperoxy radical and the chain starts anew. The dioxetane is formed separately either by [2+2]-cycloaddition or stepwise addition.

Notes: Photochemical and non-photochemical A/D-secocorrin→corrin-cyclizations of 19-carboxy- and 19-formyl-1-methylidene-1,19-secocorrinates. Decarboxylation (and deformylation) of nickel(II)-19-carboxy-(resp. 19-formyl)-corrinatesNickel (II) 1-methylidene-2,2,7,7,12,12-hexamethyl-15-cyano-19-carboxy-1,19-secocorrinate can be induced to cyclize with concomitant decarboxylation to the corresponding corrinate (Scheme 9). Experiments with deuterated derivatives (Scheme 10) indicate that in this decarboxylative A/D-secocorrin→corrin-cyclization the ring closure step precedes decarboxylation. In accord therewith is the finding that the corresponding intermediate nickel(II) 19-carboxy-corrinate (synthesized via photochemical cyclization of the corresponding cadmium complex, Schemes 6 and 9) decarboxylates under very mild conditions.Nickel(II) 1-methylidene-2,2,7,7,12,12-hexamethyl-15-cyano-19-formyl-1,19-secocorrinate cyclizes smoothly to the corresponding 19-formyl-corrinate in the presence of acetic acid/triethylamine. The formyl group of the cyclization product can be eliminated hydrolytically in essentially quantitative yield by treatment with 2N KOH in ethanolic solution (Scheme 11). The non-photochemical (A→D)-cyclization of 19-formyl-1,19-secocorrinoids represents formation of the corrin chromophore at the oxidation level of porphyrinogens and exemplifies how a C1-fragment that eventually leaves the ligand can fulfill a specific function in the (A→D)-ring closure to a corrin.

Notes: The Hydrolysis of 6exo-Substituted 2exo- and 2endo-Norbornyl p-Toluenesulfonates. Norbornane Series. Part 3Hydrolysis of the 6exo-substituted 2exo- and 2endo-norbornyl p-toluenesulfonates 1b-1 and 2b-1, respectively, in 70% dioxane led to different amounts of the following products: Unrearranged 2exo-norbornanols 3 and norbornenes 5, accompanied in somes cases by small amounts of the rearranged Rendo-epimers 4 and 6 and by norticyclenes 7. When the 6exo-substituent was a nucleophilic group as in 1e-1 and 2e-1, various amounts of tricyclic products were also formed by endo-cyclization. These results show that the 2exo- and 2endo-esters 1 and 2, respectively, react by way of different intermediates. In cases where the 6exo-substituent was an n-electron donor, as in 1m-r and 2m-r, quantitative fragmentation to (3-cyclopentenyl)acetaldehyde (13) occurred.

Notes: The radical cations and anions of naphtho [1,8-cd]-[1,2,6]thiadiazine (1) and 6,7-dihydroacenaphtho [5, 6-cd]-[1,2,6]thiadiazine (2), as well as the radical anion of acenaphtho [5, 6-cd]-[1,2,6]thiadiazine (3) have been characterized by ESR. spectroscopy. The π-spin distributions in the radical cations \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\oplus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\oplus \atop \dot{}}$\end{document} strongly resemble those in the iso-π-electronic phenalenyl radical. A prominent feature of the radical anions \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{\ominus \atop \dot{}}$\end{document} is the substantial localization of the π-spin population on the thiadiazine fragment. These findings are satisfactorily accounted for by HMO models using conventional heteroatom parameters.

Notes: Two new sesquiterpenoids, nakafuran-8 (1) and -9 (8), have been isolated from the marine sponge Dysidea fragilis and from its prey, the nudibranchs Hypselodoris godeffroyana and Chromodoris maridadilus. The structures were established by spectral analysis and chemical transformations. Both compounds possess antifeedant properties when assayed in the laboratory against common reef fishes, Chaetodon spp.

Notes: The stereospecific cis-hydroxylation of 1-(2,3-dideoxy-β-D-glyceropent-2-enofuranosyl)thymine (1) into 1-β-D-ribofuranosylthymine (2) by osmium tetroxide is described. Treatment of 2′,3′-O, O-isopropylidene-5-methyl-2,5′-anhydrouridine (8) with hydrogen sulfide or methanolic ammonia afforded 5′-deoxy-2′,3′-O, O-isopropylidene-5′-mercapto-5-methyluridine (9) and 2′,3′-O, O-isopropylidene-5-methyl-isocytidine (10), respectively. The action of ethanolic potassium hydroxide on 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5-methyluridine (7) gave rise to the corresponding 1-(5-deoxy-β-D-erythropent-4-enofuranosyl)5-methyluracil (13) and 2-O-ethyl-5-methyluridine (14).The hydrogenation of 2 and its 2′,3′-O, O-isopropylidene derivative 4 over 5% Rh/Al2O3 as catalyst generated diastereoisomers of the corresponding 5-methyl-5,6-dihydrouridine (17 and 18).

Notes: Photochemistry of Cyclic Acetals of the 1,3-Dioxa-4,6-cycloheptadiene TypeUV.-irradiation (λ=254 nm) of 3 gives the isomers (E)-5 (4%), (Z)-5 (60%) and 6 (3%). On triplet sensitization (acetone; λ ≥ 280 nm) 3 is converted to (E)-5 (3%), (Z)-5 (7%) and 7 (9%). - The 1π,π*-excitation (λ=254 nm) of 4 yields the isomers 2 (9%), 8 (10%), 9 (34%), 10 (20%) and 11 (3%). On thermolysis (200°) 4 gives 10 (87%) by a Claisen-rearrangement.

Notes: Photochemistry of Conjugated γ,δ-Epoxyenones: The Influence of a Hydroxy Substituent in ∊-PositionOn 1n, π*- or 1π,π*-excitation (λ ≥ 347 or λ=254 nm), the ε-hydroxy-γ;,δ-epoxyenone 8 undergoes fission of the C(γ)—O bond followed by the cleavage of the C(δ)-C(ε) bond. This hitherto unknown sequence of reactions is evidenced by the structure determination of the new type products 10-17 and 25, including a synthetic proof for 12 and the X-ray analysis of 11 (X-ray data: triclinic P1; a=7,386(2), b=8,904(4), c=9,684(5)Å; α=82,29(4)°, β=74,46(3)°, γ=82,29(3)°; Z=2).The selective 1π,π*-excitation also induces competitive C(γ)-C(δ) bond cleavage to yield the bicyclic acetal 18 and a ketonium-ylide intermediate a, which photochemically forms a carbene b giving the allene 19 and the cyclopropene 20.On 1n,π*-excitation of the acetate 9 the initial C(γ)-O bond fission is, in contrast to the behaviour of the corresponding alcohol 8, followed by a 1,2-methyl shift affording (E/Z)-28 or by a cyclization-autoxidation process yielding the lactone 29.

Notes: On the Synthesis of Sulfonated Derivatives of 4- and 5-AminoindanBaking the hydrogensulfate salt of 4-aminoindan (1) and 5-aminoindan (2) led, respectively, to 4-aminoindan-7-sulfonic acid (3) and 5-aminoindan-6-sulfonic acid (4). Acid 4 was also obtained by direct sulfonation of 2. 4-Aminoindan-6-sulfonic acid (5) and 6-aminoindan-4-sulfonic acid (6) were prepared by sulfonation of 4-nitroindan (7) and 5-nitroindan (9), respectively, to 4-nitroindan-6-sulfonic acid (8) and 6-nitroindan-4-sulfonic acid (10), followed by a Béchamp-reduction. Treatment of 1 with amidosulfuric acid gave 3, whereas the same reaction with 2 led to a mixture of 4 and 5-aminoindan-4-sulfonic acid (11). Independent synthesis of 11 was achieved by the following sequence of reactions: sulfur dioxide treatment of the diazonium chloride derived from 4-amino-5-nitrodan (13) gave 5-nitroindan-4-sulfonyl chloride (14); hydrolysis to 5-nitroindan-4-sulfonic acid (15), and final reduction. The 4-aminoindan-5-sulfonic acid (16) was synthesized by treatment of 4-amino-7-bromoindan (18) with amidosulfuric acid to give 4-amino-7-bromoindan-5-sulfonic acid (19) followed by hydrogenolysis. Sulfonation of 4-acetyl-amino-7-bromoindan (17) with oleum followed by hydrolysis led to 7-amino-4-bromoindan-5-sulfonic acid (20), the structure of which was confirmed by reductive dehalogenation to 5.

Notes: This paper deals with the problem of defining, and measuring, the pH inside the water pool (which we define as pHwp) of reverse micelles, i.e. micelles formed by surfactants dissolved in apolar solvents in the presence of minimal amounts of water. The conceptual and experimental difficulties are discussed, and it is argued that no absolute determination of pHwp is possible, mostly because water in the water pools of reverse micelles is a new solvent, for which no standardization of acidity is available. The problem can be approached only on the basis of an empirical acidity scale.An empirical acidity scale for water pools in reverse micelles of bis (2-ethyl-hexyl) sodium sulfosuccinate (AOT) in isooctane has been defined by measuring the 31P-chemical shifts of phosphate buffers. The chemical shifts in bulk water were compared to those found in reverse micelles under the assumption that the pK of phosphate ion is the same in the two systems. It was found that in most cases there was little difference (less than 0.4 pH units) between pHwp and the pH of the starting buffer in bulk water (which we define as pHst). However, this difference between pHwp and pHst may become much larger in certain cases.The difference (pHwp-pHst) is measured under a variety of conditions, and this permits the determination of an operational acidity in the micelle water pools as a function of the pHst with which the aqueous micelles are prepared. The significance of such data for interpreting the behaviour of enzymes confined in the micelles water pool is discussed. Based on the pHwp scale, the apparent pKa of phenol-red and 4-nitrophenol were determined in reverse micelles containing different buffers and different water content. The pKa values obtained were rather sensitive to changes of both these factors, which was taken to signify that organic dies have only a very limited applicability to measure the acidity of the water pools of reverse micelles.

Notes: Leaf-gland Pigments: 3β-Acetoxyfuerstione, Nilgherron A and Nilgherron B, New Quinomethanes from Plectranthus nilgherricus BENTH. (Labiatae); Absolute Configuration of FuerstioneWe have isolated from leaf-glands of the above mentioned plant the following deeply coloured quino-methane derivatives: (1) traces of the already known fuerstione (1a); 11,15-dihydroxy-5,7,9 (11), 13-abietatetraen-12-one; (2) the new 3β-acetoxy-fuerstione (1b); (3) nilgherron A (5a, I or II), a new dimeric diterpenoid quinomethane, C40H52O7, formed in the plant obviously by cycloaddition of the o-quinone 8 (9aS, 11R)-11 -hydroxy-2-(1-hydroxy-1-methylethyl-9,9-dimethyl-3,4,7,8,9,9a,10,11- octahydro-5H-dibenzo [a, d]cycloheptene-3,4-dione) with fuerstione; (4) nilgherron B (5b, I or II), C42H54O9, likewise a new compound, formed by the same type of cycloaddition (heterodiene synthesis) of 8 with 3β-acetoxyfuerstione. On the basis of 1H-NMR. shift arguments structure I is slightly preferred to II for 5a and 5b. Model experiments have shown the easy formation of the dihydrodioxin ring by reaction of an o-benzoquinone with p-quinomethanes. The absolute configuration of fuerstione and 3β-acetoxyfuerstione has been determined by chiroptical methods.

Notes: The bidentate phosphine 2,11-bis(diphenylphosphinomethyl)benzo [c]phenanthrene (1) has been used to prepare the mononuclear, square planar complexes trans-[MX(CO)(1)] and trans-[M(CO)(CH3CN)(1)][BF4] (M = Rh, Ir; X = Cl, Br, I, NCS). It is found that the tendency of these complexes to form adducts with CO, O2 and SO2 is significantly lower than that of the corresponding Ph3P complexes. The oxidative-addition reactions of complexes trans-[IrX (CO) (1)] with hydrogen halides give the six-coordinate species [IrHX2(CO) (1)]. The complexes [IrH2I (CO) (1)] and [IrH2L (CO) (1)] [BF4] (L = CO and CH3CN) have been obtained from hydrogen and the corresponding substrates. The model compounds trans-[MCl (CO) (Ph2PCH2Ph)2] (M = Rh, Ir), trans-[Ir (CO) (CH3CN) (Ph2PCH2Ph)2] [BF4], [IrHCl2(CO)(Ph2PCH2Ph)2] and [IrH2(CO)2(Ph2PCH2Ph)2] [BF4] have been prepared and their special parameters are compared with those of the corresponding complexes of ligand 1. The influence of the static requirements of this ligand on the chemistry of its rhodium and iridium complexes is discussed.

Notes: The preparation of the ditertiary phosphines 2,11-bis (di-m-tolylphosphinomethyl)benzo [c]phenanthrene (1b), 2,11-bis (di-p-anisylphosphinomethyl)benzo-[c]phenanthrene (1c), 2,11-bis (di-m-trifluoromethylphenylphosphinomethyl) benzo-[c]phenanthrene (1d), 2,11-bis (dicyclohexylphosphinomethyl)benzo [c]phenanthrene (1e) and 2,11-bis [di-(t-butyl)phosphinomethyl]benzo [c]phenanthrene (1f), by a combination of synthetic routes is described.

Notes: On the Pathway of the Catalytic Reduction of 7-MethylpterinThe catalytic hydrogenation of 7-methylpterin (VII) in a neutral solution occurs first by the reduction of the 7,8-double bond (thermodynamically-controlled reaction) followed by the reduction of the 5,6-double bond. On the contrary, in an acidic medium like CF3COOH, the 5,6-double bond is reduced first (kinetically-controlled reaction). The dihydro-intermediate then undergoes a [1,2]-H-rearrangement leading to the formation of the thermodynamically more stable 7-methyl-7,8-dihydropterin (XV) which on further reduction gives 7-methyl-5,6,7,8-tetrahydropterin (VIII). The catalytic reduction of 7-methyl-7,8-dihydropterin (XV) with deuterium gives stereoselectively a sole product with D at C(6) in the equatorial position.

Notes: The Photochemistry of Open-Chained 2,6- or 2,7-Dien-Carbonyl CompoundsOn 1n, π*-excitation (λ 〉 347 nm) citral (5) and the methyl ketone 10 isomerize to compounds A (7, 19) and B (6, 20), whereas the phenyl ketone 11 changes into the isomer 24 of type E. Evidence is given that the conversions to A and B may arise from the 3n, π*-state of the 2,6-diene-carbonyl compounds.On 1n, π*-excitation (λ = 254 nm) 5 and 10 yield the isomers A (7, 19) and D (18, 22), but no products of type B. Furthermore, conversion of 10 to the isomer 21 of type C is observed.Selective 1n, π*-excitation (λ = 254 nm) as well as selective 1n, π*-excitation (λ 〉 347 nm) of the 2,7-diene-carbonyl compounds 12 and 13 give rise to isomerization to the compounds F (25, 28), exclusively. The intramolecular [2 + 2]-photocycloadditions are shown to be triplet processes.UV.-irradiation (λ 〉 280 nm) of compounds F (25, 28) furnishes the isomeric products G (26, 29) which photoisomerize to oxetanes of type H (27, 30).

Notes: Four triterpenoid saponins (1-4) have been isolated from the berries of Hedera helix L. (Araliaceae) by droplet counter-current and preparative liquid chromatography. The structures have been established by FD./MS. and 13C-NMR. spectroscopy. The isolated compounds were found to possess strong molluscicidal activity against the bilharziasis-transmitting snail Biomphalaria glabrata. Saponin 4, identified as hederagenin 3-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside, is a new natural product.

Notes: Synthesis and Photochemistry of 3-(2-Thienyl)-2,2-dimethyl-2H-azirineThe synthesis of 3-(2-thienyl)-2,2-dimethyl-2 H-azirine (1) is described. UV. irradiation of 1 in benzene solution generates the nitrile isopropylide 2 which reacts in a regiospecific manner with activated C, C and C, O double bonds to give 1-pyrrolines and 3-oxazolines, respectively. With chelidonic acid diethyl ester the cycloaddition of 2 to the C, C double bond is preferred.

Notes: Synthesis of optically active natural carotenoids and structurally related compounds. IV. Synthesis of (3R, 3′R, 6′R)-luteinThe synthesis of (3R, 3′R, 6′R)-lutein (19) according to the building principle C25+C15=C40 is reported utilizing (R)-4-hydroxy-2,6,6-trimethyl-2-cyclohexen-1-one (4) as a readily available key intermediate.

Notes: Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. VIII. Synthesis of (3S,3′S)-7,8,7′,8′-Tetradehydroastaxanthin and (3S,3′S)-7,8-Didehydroastaxanthin (Asterinic Acid)The synthesis of all-trans-(3S,3′S)-3,3′-dihydroxy-7,8, 7′,8′-tetradehydro-β, β-carotene-4,4′-dione (1), of all-trans-(3S,3′S)-3,3′-dihydroxy-7, 8-didehydro-β,β-carotene-4,4′-dione (2) (asterinic acid = mixture of 1 and 2), and of their 9,9′-di-cis- and 9-cis-isomers is reported starting from (4′S)(2E)-5-(4′-hydroxy-2′, 6′,6′-trimethyl-3′-oxo-l′-cyclohexenyl)-3-methyl-2-penten-4-ynal (8). The absolute configuration (3S,3′S) for both components 1 and 2 of asterinic acid ex Asterias rubens is confirmed on the basis of spectroscopic and direct comparison.

Notes: Isolation of (-)-dunnione from the leaves of Calceolaria integrifolia, MURR. (fam. Scrophulariaceae)From the leaves of Calceolaria integrifolia, a plant often used in horticulture. partially racemic (-)-dunnione (1) has been isolated. This seems to be the first record of its occurrence outside the family Gesneriaceae, where it previously has been found in two species as the (+)-enantiomer.

Notes: A chiral economic synthesis of (R)- and (S)-muscone using the cyclofragmentation of epoxysulfonesStarting with isobutyric acid (2) and using a microbiological oxidation with pseudomonas putida (S)-β-hydroxy-iso-butyric acid (3) has been prepared. From this /pseudosymmetrical: (see text) intermediate the two enantiomeric bromo derivatives 8 (R) and 20 (S) have been synthesized (cf. scheme 4) by altering the sequence of the reactions (cf. scheme 3). A Grignard reaction starting from the two bromo compounds 8 and 20 and from cyclododecanone 1 produced after hydrogenolysis the two enantiomeric dialcohols 9 and 21 (1 + 8 → 9, 1 + 20 → 21, cf. scheme 5). The subsequent transformations led to the two enantiomeric olefin derivatives 12 and 24. Oxidation of 12 with peracid produced a mixture of the two epoxy-sulfones 13 and 14 (cf. scheme 6). The olefin-derivative 24 was oxidized to the corresponding mixture of 25 and 26. A one pot cyclofragmentation (cf. [4] and scheme 6) produced a mixture of (E)- and (Z)-3-methylcyclopentadec-4-en-1-one (13 + 14 → 15 + 16, 25 + 26 → 27 + 28). The final hydrogenation led to natural (R)- and unnatural (S-muscone (3-methylcyclopentadecanone). The achiral starting material has been transformed to the desired optically active target products without loss of material with undesired absolute configuration. The authors used the notion of chiral economic synthesis to characterize synthetic sequences with the above mentioned features.

Notes: The structures of cyclic polyketones, their hydrates and reduction products were studied in different solvents by 13C-NMR. spectroscopy. In dimethylsulfoxide solution rhodizonic acid (1), croconic acid (2) and squaric acid (3) exhibit signal averaging. In anhydrous tetrahydrofuran 1 and 2 could be observed as non-dynamic species. The spontaneous reactions of dodecahydroxycyclohexane (5) and decahydroxycyclopentane (‘leuconic acid’) (6) and the sequence of formation of ring-contracted products were investigated. Key intermediates could be clearly identified which support the mechanism proposed earlier involving a benzylic acid type rearrangement followed by decarboxylation and subsequent redox reactions.

Notes: In order to test the effects of the replacement of phenylalanine by carboranylalanine (Car) in biological ligand-acceptor interactions, Z · Ala-Ala-Car · OH (1) and Ac · Car · OEt (2) were synthesized and their reactions with chymotrypsin studied. The two compounds proved to be good inhibitors with K(i) values of 3 · 10-4M (1) and 8.6 · 104M (2); the K(i) of Z · Ala-Ala-Phe · OH (1a) is 1 · 10-3M. The inhibition constants were determined by a new photolytic technique, inhibition of photoaffinity labelling by Z · Ala-Ala-Phe(pN3) · OH. Ac · Car · OEt is not hydrolysed by chymotrypsin. The findings indicate that the carboranyl group can interact with the ‘phenyl recognition site’ of the enzyme to produce the binding that is characteristic of aromatic amino acid residues. However, some kind of distortion in the region of the ‘mechanistic site’ must be postulated in order to account for the failure of hydrolysis. Some possible effects of the replacement of aromatic amino acids by Car in peptide hormones on hormone-receptor interactions are discussed.

Notes: 1,3-Cyclobutanedione derivatives from keteneThe dimerisation of ketene leads mainly to the methylidene-β-lactone ‘Diketene’ 2c. It is shown, that also a small amount of the symmetrical dimer, 1,3-cyclobutadione 1c is produced, which under the reaction conditions is acetylated to 3-acetoxycyclo-butenone (5).

Notes: Synthese von 4-(4′-Methyl-2′-oxo-cyclohex-3′-en-1′-yl)-pentanal und dessen Umwandlung in Spiro[4.5]decan- und 1,6,7,7a-Tetrahydro-2H-inden-DerivateEs wird die Synthese von 4-(4′-Methyl-2′-oxo-cyclohex-3′-en-1′-yl)-pentanal als ein (1:1)-Gemisch von zwei Diastereoisomeren 10A und 10B auf folgendem Weg beschrieben: Die Umsetzung des Grignard-Reagens von 1,1-Äthylendioxy-3-brom-propan (2) mit 2-Methoxy-4-methyl-acetophenon (1) ergab 1,1-Äthylendioxy-4-hydroxy-4-(2′-methoxy-4′-methyl-phenyl)-pentan (3), welches sich mit methanolischer Salzsäure in 2-Methoxy-5-(2′-methoxy-4′-methyl-phenyl)-5-methyl-tetrahydrofuran (7A,B) umwandeln liess. Durch Birch-Reduktion von 7A,B wurde 4-(2′-Methoxy-4′-methyl-cyclohexa-1′,4′-dien-1′-yl)-pentan-1-ol (8), und danach durch milde Hydrolyse 4-(4′-Methyl-2′-oxo-cyclohex-3′-en-1′-yl)-pentan-1-ol (9A,B)2 erhalten. Oxydation von 9A,B lieferte schliesslich den erwähnten Keto-aldehyd 10A,B. Einige Produkte von Nebenreaktionen, nämlich 4, 5, 11, 12 und 13A,B, sind auch beschrieben.Der Keto-aldehyd 10A,B liess sich in ein Gemisch, bestehend aus drei Diastereo-isomeren A, B und C von 1-Hydroxy-4,8-dimethyl-spiro[4.5] dec-7-en-6-on (15) und aus zwei Diastereoisomeren A und B von 1,5-Dimethyl-1,6,7,7a-tetrahydro-2H-inden-3-carbaldehyd (14), umwandeln. Für diese aldolartigen Cyclisierungen wurden vier verschiedene Methoden verwendet: (a) Stehenlassen in Tetrachlorkohlenstoff-lösung, (b) Behandlung mit etwas Trifluoressigsäure in Chloroformlösung, (c) und (d) Schütteln einer Ätherlösung mit wässeriger Salzsäure oder Natronlauge. Oxydation von 15A und 15C lieferte eines der Diasteroisomeren von 4,8-Dimethyl-spiro[4.5]-dec-7-en-1,6-dion (16A), und Oxydation von 15B führte zum anderen (16B).

Notes: Synthesis of fulvenes via 1-chloroaklyl-acetatesThe synthesis of fulvenes (5) via l-chloroalkyl acetates (3) is extended to 6-alkyl-fulvenes with branched side-chains, to 6-phenylfulvene (5f) and 6-(2-furyl)fulvene (5g), as well as to 6-vinylfulvenes (5h and 5i) containing chlorine and acetoxy-substituents in ω-position. The reaction is carried out at low temperature under water-free conditions. The purification of the reaction products is simple. - An improved procedure for the preparation of pure fulvene (5a, R=R′=H) is reported.

Notes: Activated quinones: substitution reactions by methoxy-carbonyl-1,4-benzoquinone of azulenes, benzofuran and indoles; regiospecific syntheses of polymethoxy-fluorenones; a new synthesis of the 2,6-dihydro-naphtho[1,2,3-cd]indol-6-one system.We present new electrophilic substitution reactions of azulenes and 5-membered heterocyclics by methoxy-carbonyl-1,4-benzoquinone. Hydroquinones 3a and 5 are prepared from azulene, and 3b from guaiazulene (see Scheme 1). Benzofuran undergoes α- and β-substitution (hydroquinones 9 10) (see Scheme 2). Only β-substitution is observed with indole (hydroquinone 20) (see Scheme 4). After methylation, saponification and intramolecular acylation of the substituted indoles 22c, 22d, derivatives of 2,6-dihydro-naphtho[1,2,3-cd]indol-6-one have been obtained. Spectral data prove the presence of the methylidenequinone tautomer. By protonation or alkylation at the carbonyl group of 23, the violet, highly delocalized 16π-electron systems 25 are generated. Analogously, polymethoxy-fluorenones have been prepared from methoxylated diphenylquinones 15 (see Scheme 3). They also are transformed by protonation and alkylation to the highly coloured and delocalized 12 π-electron systems 18. By contrast, anthracene is not substituted by methoxycarbonyl-1,4-benzoquinone, but undergoes cycloaddition to the triptycene derivative 1 (see Scheme 1). A summary is presented of previously described reactions of activated quinones.

Notes: Study of Electron-Impact Fragmentation of Benzothiazole DerivativesThe mass spectra of eighteen substituted benzothiazoles are reported and discussed. All these compounds are thermodynamically stable and give an intense molecular ion, which undergoes different types of fragmentation depending on the nature of the substituent which is rarely eliminated directly. β-Cleavage with respect to the heterocyclic double bond is often observed. Specific 2H-, 13C-, 15N- and 34S-labelling have been used in order to confirm the fragmentation patterns.

Notes: The base hydrolysis of the optically active title compound proceeds with full racemization whilst the meridional arrangement of the diethylenetriamine ligand is fully retained. The optically active hydroxo complex prepared independently with retention of configuration racemizes ≳ 104 times slower. This unique result is discussed in terms of the classical π-stabilization hypothesis for the base hydrolysis mechanism.

Notes: An efficient and flexible method for the preparation of silyl nitronates is described (see 1-10). NMR. spectral investigations indicate a rapid 1,3-silyl migration process, with an activation energy of about 10 kcal mol-1. X-ray crystallographic studies on the silyl nitronates 3 and 8 show structures that lean towards an SN2 retention pathway at silicon.

Notes: Astaxanthin (1; 3,3′-dihydroxy-β,β-carotene-4,4′-dione) isolated from lobster eggs (Homarus gammarus) was unexpectedly found to be a mixture of all three optical isomers as determined by HPLC. analysis of the corresponding diesters of (-)-camphanic acid. This is the first finding of meso-astaxanthin and a meso-carotenoid in general in nature.

Notes: Enhancement of Detection Sensitivity of Cyclosporin A by Derivatization with 2-NapthylselenylchlorideThe UV./HPLC. detection sensitivity of cyclosporine A 1, an immunosuppressive cyclic undecapeptide containing one D-aminoacid and seven N-methylated aminoacids, is enhanced by a factor of 3-4 (limit of detection 5 ng) by conversion of the characteristic side chain of amino-acid-1 to the β-naphthylseleno-substituted tetrahydrofuran derivative 4.

Notes: An ab initio study of α-seleno carbanions show that they are subject to appreciable polarization and stereoelectronic effects. Like in α-thia carbanions, the equatorial e forms are more stable than the axial a forms, one of the stabilizing contributions being the conformation dependent (C-lone pair, σ* Se—Z) interaction. The carbanion stabilizing effect of the α-Se atom is about 3 kcal/mol larger than that of the sulfur analog. As in the case of the sulfur no specific effect of the d orbitals is found.

Notes: The radical anions of 6a-thiathiophthenes ([1,2]dithiolo[1,5-b] [1,2]dithioles), I(R), convert into those of 4H-thiapyran-4-thiones, III(R), via cis-trans isomerization. The reaction is slowed down when the size of the substituent R in the 2,5-positions of 6a-thiathiophthene increases, and it is prevented by the introduction of a 3,4-polymethylene bridge. The primary and the secondary radical anions, I(R)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document} and III(R)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, respectively, exhibit very similar hyperfine splitting patterns. E.g., in the case of the unsubstituted 6a-thiathiophthene, I(H), and 4H-thiapyran-4-thione, III(H), the proton coupling constants are aH2,5=6.72 and aH3,4=1.73 Gauss for I(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, and aH2,6=6.35 and aH3,5=2.07 Gauss for III(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. In contrast to I(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, cis-trans isomerization could not thus far be proved to occur with its 1,6-dioxa-analogue, IV(H)\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, since no ESR. spectrum of the radical anion of 4H-pyran-4-thione, V(H), was detected upon reduction of IV(H).

Notes: Leaf-gland Pigments: Coleon L, a New Diosphenolic Compound from Coleus somaliensis, S. MOORE; Revision of the Structures of Coleon H, I, I′ and KFrom leaf-glands of C. somaliensis a new, highly oxidized diosphenolic hydroquinone belonging to the abietane series was isolated in minute quantities. The new compound, coleon L (4c; C24H30O10), is very labile and transformed into its tautomer coleon K (5d) on standing in solution. 1H-NMR. spectra of coleon L showed clearly that the points of attachment of the two acetoxy groups are at C(3) and C(16) contrary to the positions expected from our previously published structure 3 for coleon K. Application of a recently elaborated conversion of trans-A/B-6,7-diketones of type 5 into the cis-isomers 6 allowed to assign unambiguously the β-configuration to the hydroxyl group at C(3) using pyridin induced solvent shifts. This confirmed structure 4c and 5d for coleon L and K, respectively. Based on similar reasons, the configuration at C(3) of coleon H, I and I′ had to be revised, the structures of these coleons being 4b, 5b and 5c, respectively.

Notes: The ESR. spectrum of the relatively unstable radical anion of diphenylcyclo-propenone (II) has been observed upon electrolytic reduction of II in N,N-di-methylformamide and 1,2-dimethoxyethane. Simple MO models account well for the π-spin distribution and for the restricted rotation of the phenyl substituents in II\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. A rather facile loss of a CO molecule by II\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document} results in formation of the radical anion of tolane (diphenylacetylene; III). No ESR. spectra could be obtained for the radical anions of dialkylcyclopropenones which are even shorter-lived than II\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, although decay by decarbonylation seems to be less favoured with them than with II\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. In presence of air, electrolytic reduction of either II or its dimethyl and di-t-butyl analogues yields the correspondingly disubstituted semidione anions.

Notes: Reactions with derivatives of γ-chloroacetoacetic acidEthyl γ-chloroacetoacetate reacts with ammonia to give ethyl β-amino-γ-chloro-crotonate; with aniline, however, β-anilino-crotonic acid γ-lactone is formed. The reaction of ethyl α-cyano-γ-chloro-acetoacetate with arylamines yields 1-aryl-2-amino-3-ethoxycarbonyl-pyrrolin-4-ones.

Notes: The Structure of Cyclosporin CThe structure of cyclosporin C (2), a minor antifungal metabolite from Trichoderma polysporum (Link ex Pers.) RIFAI has been elucidated. Hydrolytic cleavage and spectroscopic evidence show that cyclosporin C is a neutral oligopeptide of 11 amino acids linked together in a 33-membered ring. Cyclosporin C (2) differs from the main metabolite cyclosporin A (1) [2] [4] only by containing L-threonine in the place of L-α-aminobutyric acid as has been shown by the conversion of 2 into 1. 13C-NMR. spectra and study of molecular models suggest that cyclosporin C (2) has the same molecular conformation as 1, which is best described as a twisted β-pleated sheet held together in a conformationally stable form by intramolecular hydrogen bonding.

Notes: Incorporation experiments with (3H and 14C) doubly labelled farnesols into cantharidinAfter injection of 11′, 12-[3H]-7-[14C]-farnesol or 11′, 12-[3H]-5,6-[14C]-farnesol, the 3H-label is located specifically in the C(9)-methyl-group of cantharidin, whereas the 14C-labelling pattern follows an incorporation via acetic acid (Scheme 4). C-Atoms 5, 6 and 7 from the middle part of the farnesol molecule are utilized for cantharidin biosynthesis to an extent that is about 2.1-11% of the incorporation rate of the methyl groups C(11′) and C(12), depending on the position of the 14C-label in farnesol. These results confirm our earlier hypothesis [1] that the C10-molecule cantharidin is biosynthesized from the C15-precursor farnesol which is cleaved between C(1)-C(2), C(4)-C(5), and C(7)-C(8). The synthesis of 7-[14C]-farnesol and of 5,6-[14C]-farnesol is described.

Notes: Synthesis and NMR. Spectra of Novel Lanthanide-Cobalt Sandwich CompoundsThe reaction of [(C5H5)Co{P(O)(OR)2}2{P(OH)(OR)2}] (3, R = CH3, C2H5) with lanthanide(III) compounds yields the cationic trinuclear complexes [{(C5H5)Co[P(O)(OR)2]3}2Ln]⊕X⊖ (2, R = CH3, C2H5; Ln = La, Eu, Pr; X = BF4, BPh4). According to thermogravimetric and NMR. studies these compounds do not contain additional coordinated water molecules. It is therefore supposed that the central lanthanide ion has a regular sixfold coordination of phosphoryl ligands. The 31P- and 1H-NMR. spectra of 2 (R = CH3; Ln = La, Eu, Pr) and 3 are discussed. It can be shown that the Fermi contact shift as well as the coordination shift make significant contributions to the observed lanthanide induced shift of the cyclopentadienyl signal.The dominating influence of the Fermi contact interaction on the 31P chemical shift is in accord with theoretical considerations and comparable experimental values. The temperature dependence of the proton chemical shifts of 2 (R = CH3; Ln = Eu) is also discussed.

Notes: Stereoselectivity and Reactivity in the 1,3-Dipolar Cycloaddition of Chiral N-(Alkoxyalkyl)nitronesThe stereoselectivity in the reaction of hydroxy-oxime 1 with acetaldehyde and methyl methacrylate yielding the diastereomeric isoxazolidine-ribosides 9-12 was determined to be 93%. The predominant adducts 9 and 10 were cleaved to the diastereomeric isoxazolidines 19 and 20, respectively, which upon oxidation gave the same optically active 2-isoxazoline 21, thus demonstrating the participation in the cycloaddition of both (E/Z)-isomeric nitrones 13 and 14. Based upon comparison of the optical rotations, the isoxazolidines 7, 8, 19 and 20 and the 2-isoxazolines 21 and 22 possess the same chirality, found to be R by correlating 7 with (+)-(S)-citramalic acid. - Since the hydroxy-oximes 1 and 36 showed the same stereo-selectivity in the reaction with formaldehyde and methyl methacrylate, the trityl group of 1 does not influence the stereoselectivity in the cycloaddition. The hydroxyoxime 38 led in the same type of reaction to the isoxazolidines 7, 8, 19 and 20 possessing (S)-chirality, the stereoselectivity (79-95%) being similar to the one observed with 1 (67-95%). The explanation of this stereoselectivity is based upon a stereoelectronic effect in the transition state of the cycloadditions (kinetic anomeric effect). As predicted, the N-(alkoxyalkyl)nitrones showed enhanced reactivity in the cycloaddition with unactivated olefins (leading to 47, 48, 50 and 51). The importance of exo vs. endo approach of the dipolarophile was evidenced by reacting 1 with formaldehyde and methyl acrylate giving predominantly 57 with (5S)-configuration. - Use of the hydroxy-oxime 65 allows synthesis of optically active isoxazolidines with regeneration of the starting hydroxy-oxime.

Notes: The Constitution of LoroglossineLoroglossine, a characteristic constituent of orchids, is shown to be bis[4-(β-D-glucopyranosyloxy)-benzyl]-(2R, 3S)-2-isobutyl-tartrate (1). Base catalysed hydrolysis and esterification with diazomethane gave 1 mol-equiv. of dimethyl (+)-2-isobutyl-erythro-tartrate ((+)-3) and 2 mol-equiv. of a glucoside which after acetylation formed 4 identical with a synthetic sample. The structure of (+)-3 follows from the synthesis of (±)-3 by osmium tetroxide oxidation of isobutyl-maleic acid anhydride and subsequent esterification. The absolute configuration of (+)-3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 15 and 16 and pure 15 with (S)-(+)- and (R)-(-)-α-phenyl-butyric acid, respectively.

Notes: Heterocyclic dienamines III. A re-examination of the reaction of Fischer's base on tetracyanoethyleneDepending on the order of addition, Fischer's base 5 (1,3,3-trimethyl-2-methylidene-indoline) reacts 1:1 with tetracyanoethylene to give either the tricyanovinylation product 6 or the spiro compound 7. A skeletal rearrangement of a zwitterionic intermediate can explain the formation of the spiro compound. The latter undergoes a thermal isomerization yielding by ring expansion the tetrahydroquinoléine 8. On reaction with LiAlH4 or CH3ONa 7 and 8 lead both to triazatetracycles. All structures are assigned on the basis of spectral data.

Notes: L-Cα-t-Butylglycine (Bug), its amide, methyl ester, and Nα-t-butoxycarbonyl derivative were prepared by an asymmetric synthesis, and the Hansch side-chain hydrophobic (lipophilicity) parameter determined. A new enkephalin analogue, H · Tyr-D-Ala-Gly-Phe-Bug · NH2 was synthesized which is pharmacologically active in two in vitro assays and strongly resistant against a number of enzymes in vitro.

Notes: Reaction of the 1-substituted-3-cyano-isothioureas 6 with hydroxylamine gave mixtures of the 5-amino-3-substituted-amino-1,2,4-oxadiazoles 1 and the isomeric 3-amino-5-substituted-amino-1,2,4-oxadiazoles 8 in which 1 usually predominated. The structural assignment of these products is discussed. In a second method, the 2-hydroxy-1-methyl-1-phenyl-guanidine 15 was converted to the corresponding 3-disubstituted-amino-5-trichloromethyl-1,2,4-oxadiazole 16, a precursor to the 5-amino derivatives 17 by nucleophilic displacement of the trichloromethyl group.