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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 2327-2335 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 58 (1993), S. 1967-1969 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 52 (1987), S. 3821-3825 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: A selection of stereoisomeric 2-hydroxy-1-cyclopentanecarboxamides, a 4-tert-butyl derivative and three tert-butyl derivatives of the respective carboxylic acid were subjected to X-ray crystallography. The optically active molecules (I)–(VI) form racemic crystals. Each racemic structure is basically determined by two intermolecular hydrogen bonds of O—H...O=C—XH and O=C—X—H...OH types (X = O, NH). The partially similar patterns of close packing observed reflect five basic forms of supramolecular self-assembly. In the racemic crystals of chiral molecules, there are homo- and heterochiral chains of molecules formed by the principal (O—H...O=C) hydrogen bonds. These chains assemble either in a parallel or antiparallel mode. The parallel homochiral chains (hop) observed in structure (II), (1R*,2R*)-2-hydroxy-1-cyclopentanecarboxamide, demand the polar space group Pca21, while the parallel heterochiral chains (hep) are organized in antiparallel layers with space group P21/n in structure (VI), (1R*,2S*,5R*-5-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid). Heterochiral chains in an antiparallel array (hea) are found in (I), (1R*,2S*)-2-hydroxy-1-cyclopentanecarboxamide, and (V) [(1R*,2S*4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, space group P21/c]. Structures (IV), (1R*,2S*,4R*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, and (III), (1R*,2R*,4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxamide, reveal that homochiral chains in an antiparallel array (hoa; cross-linked by heterochiral dimers held together by the second hydrogen bonds) can be formed by either translation (space group P\bar 1) or a screw axis (space group P21/c). These alternatives are denoted hoa1 and hoa2. Similarly, within each pattern (hea, hep and hop) two slightly different alternatives can be expected. The partial similarities in the identified five patterns of hydrogen bonding are described by graph-set notations. Structures (I), (IV) and (V) can be characterized by a common supramolecular synthon, while the highest degree of similarity is shown by the isostructurality of (I) and (V).
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  • 5
    ISSN: 1434-4475
    Keywords: 3,1-Perhydrobenzoxazines ; 3,1-Perhydrobenzothiazines ; Conformational analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Aus den stereoisomerencis- undtrans-2-Hydroxymethyl-1-cyclohexylaminen und ihrenN-Methyl- undN-Benzylderivaten (4 a–c,5 a–c) wurden mit Ethylisothiocyanat die entsprechenden Thiocarbamate (6 a–c,7 a–c) erhalten. Behandlung der Verbindungen6 und7 mit Methyljodid und anschließend Alkali ergab die 3,1-Perhydrobenzoxazine8 a–c,9 a–c, während mit HCl die Cyclisierung zu den 3,1-Perhydrobenzothiazinen10 a–c,11 a–c eintrat. Es wurde festgestellt, daß die bevorzugte Konformation derN-unsubstituiertencis-Isomeren8 a und10 a die „N-innen“-Form ist, während die derN-substituierten Derivate8 b,c und10 b,c bevorzugt in der „N-außen“-Form vorliegen.
    Notes: Abstract With ethyl isothiocyanate, the stereoisomericcis- andtrans-2-hydroxymethyl-1-cyclohexylamines and theirN-methyl andN-benzyl derivatives (4 a–c,5 a–c) furnished the corresponding thiocarbamates (6 a–c,7 a–c). Treatment of compounds6 and7 with methyl iodide and subsequent alkali treatment afforded 3,1-perhydrobenzoxazines8 a–c,9 a–c, while cyclization of compounds6 and7 to the 3,1-perhydrobenzothiazines10 a–c,11 a–c was performed with HCl. It was found that the predominant conformation of theN-unsubstitutedcis isomers8 a and10 a is theN-inside form, while theN-substituted derivatives8 b,c and10 b,c have theN-outside preferred conformation.
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  • 6
    ISSN: 1434-4475
    Keywords: Condensation of 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene with lactim ethers and 2-bromopyridine ; Oxo-thio exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Für pharmakologische Untersuchungen synthetisierten wir die folgenden tetracyclischen Ringsysteme und deren Derivate: Trimethylen-thieno-[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-on und -4-thion (1 a, 5 a); Tetramethylen-thieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-on und 4-thion (1 b, 1 j, 5 b); Pentamethylen-thieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-on und-4-thion (1 c, 5 c); Trimethylen-thieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-on und -4-thion (1 d, 5 d); Tetramethylen-thieno[2,3—d]tetrahydropyrido-[1,2–a]pyrimidin-4-on und -4-thion (1 e, 5 e); Pentamethylen-thieno[2,3—d]tetrahydropyrido[1,2–a]pyrimidin-4-on und -4-thion (1 f, 5 f); Trimethylenthieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on und -4-thion (1 g, 5 g); Tetramethylen-thieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on und -4-thion (1 h, 5 h); Pentamethylen-thieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on und -4-thion (1 i, 5 i); Tetramethylen-thieno[2,3—d]-tetrahydropyrido[1,2—a]pyrimidin-4-on (7 b); Pentamethylen-thieno[2,3—d]-tetrahydropyrido[1,2—a]pyrimidin-4-on (7 c). Die Verbindungen1 a–i wurden aus 2-Amino-3-(ethoxycarbonyl)-4,5-polymethylenthiophenen (2 a–c) mit den entsprechenden Lactimethern in Chlorbenzol mit Polyphosphorsäure-Katalysator dargestellt. Die Verbindungen7 b und7 c wurden aus β-Aminosäureestern2 b–c und 2-Brompyridin (6) synthetisiert. Die Thionderivate (5 a–i) erhielten wir durch die Reaktion der Verbindungen1 a–i mit Phosphor(V)-sulfid.
    Notes: Abstract The following tetracyclic ring systems and their derivatives have been synthesized for pharmacological investigations: Trimethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 a, 5 a); Tetramethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 b, 1 j, 5 b); Pentamethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and-4-thione (1 c, 5 c); Trimethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 d, 5 d); Tetramethylenethieno[2,3—d]tetrahydropyrido[1,2,—a]pyrimidin-4-one and -4-thione (1 e, 5 e); Pentamethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 f, 5 f); Trimethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 g, 5 g); Tetramethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on and -4-thione (1 h, 5 h); Pentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 i, 5 i); Tentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one (7 b); Pentamethylenethieno-[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one (7 c). Compounds1 a–i were synthesized from 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene2 a–c with the corresponding lactim ethers (3 a–c) in chlorobenzene in the presence of polyphosphoric acid (PPA). Compounds7 b and7 c were obtained in the reaction of β-amino acid esters2 b and2 c with 2-bromopyridine (6). The thione derivatives (5 a–i) were prepared from compounds1 a–i with phosphorus(V) sulphide.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 116 (1985), S. 857-868 
    ISSN: 1434-4475
    Keywords: 1,1′-Carbonyldiimidazole ; Substituted 1,3-oxazine-2,4-diones with condensed skeleton ; IR ; 1H-NMR ; 3C-NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung cis- undtrans-N-Alkyl-,N-Aralkyl- undN-Aryl-2,4-dioxo-, tri- und tetramethylen-perhydro-1,3-oxazine wurden aus 2-Carboxamido-1-cycloalkanolen und 1,1′-Carbonyldiimidazol dargestellt. Mit Hilfe der IR,1H- und13C-NMR Spektroskopie wurden die Struktur, diecis- odertrans-Annellierung der Ringe und die bevorzugte Konformation der flexiblencis-Isomeren im Vergleich zumcis-trans Isomerenpaar nachgewiesen. Ähnlich zu den früher untersuchten 1,3-Oxazine-2- und -4-onen ist hier ebenfalls das „O-endo“ Konformere bevorzugt; in diesem ist der Sauerstoffaxial angeordnet, und zwar unabhängig von der Zahl der alicyklischen Ringatome und dem flexibleren Oxazindionring.
    Notes: Abstract N-Substituted-2-carboxamido-1-cycloalkanols were cyclized with 1,1′-carbonyldiimidazole to synthesizecis- andtrans-N-alkyl-,N-aralkyl- andN-aryl-2,4-dioxo tri- and tetramethyleneperhydro-1,3-oxazines. The structures of the compounds and theircis ortrans ring anellation were confirmed by IR,1H- and13C-NMR spectroscopy, and thecis andtrans pairs of isomers were compared to establish the predominant conformation of the flexiblecis isomers. It was found that—similarly to the 1,3-oxazin-2- and -4-ones studied earlier—the “O-endo” conformers are preferred, in which the 1-oxygen atom isaxial to the alicyclic ring; this is independent of the number of ring atoms in the alicycle, and of the presence of an oxazinedione ring, even though this is more flexible that the ring of oxazinones.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 117 (1986), S. 97-104 
    ISSN: 1434-4475
    Keywords: C=O Stretching frequencies ; 5,6-Polymetylenepyrimidin-4(3H)-ones ; Seth-Paul-Van Duyse equation ; Substituent effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden die C=O-Streck-Frequenzen von 32 5,6-Polymethylenpyrimidin-4(3H)-onen (1a–1w) undcis-5,6-polymethylen-5,6-dihydropyrimidin-4(3H)-onen (2a–2h) in CCl4 und CHCl3 gemessen und mit den SubstituentenkonstantenX + (R) im Sinn der modifizierten und erweitertenSeth-Paul-Van Duyse-Gleichung korreliert. Es wurde festgestellt, daß die C=O-Streck-Frequenzen und die Übertragung von Substituenteneffekten durch den heterocyclischen Ring von der Größe des kondensierten Kohlenwasserstoffringes signifikant beeinflußt werden. Es konnte belegt werden, daß in Molekülen, die mit Wasserstoffbrücken verbunden sind, die Substituenteneffekte vorwiegend über den C=N−C=C-Teil des Pyrimidinonringes zur C=O-Gruppe übertragen werden. In den freien Molekülen erfolgt die Übertragung der Substituenteneffekte hauptsächlich über die NH-Gruppe.
    Notes: Abstract The C=O stretching frequencies of 32 5,6-polymethylenepyrimidin-4(3H)-one (1a–1w) andcis-5,6-polymethylene-5,6-dihydropyrimidin-4(3H)-one (2a–2h) derivatives were measured in tetrachlormethane and in chloroform and correlated with the substituent constantsX + (R) in the sense of the modified and extendedSeth-Paul-Van Duyse equation. It was found that the C=O stretching frequency and the transmission of substituent effects through the heterocyclic ring are significantly influenced by the size of the fused hydrocarbon ring. Evidence was obtained that in molecules linked by intermolecular hydrogen bonds the substituent effects are transmitted to the C=O group predominantly via the C=N−C=C part of the pyrimidinone ring. In the free molecules the transmission of substituent effects takes place mainly through the NH group.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 120 (1989), S. 463-471 
    ISSN: 1434-4475
    Keywords: 2H-1,3-Benzothiazines ; 3,4-Dihydro-2H-1,3-benzothiazines ; 4H-1,3-Benzothiazines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Aus 6,7-Dimethoxy-3-methyl-2H-1,3-benzothiaziniumjodid (2) wurde mit Methylmagnesiumjodid (±)-Thiacarnegin (3) dargestellt. Diese Reaktion bietet ein neues Verfahren für die Synthese von 4-substituierten Dihydro-2H-1,3-benzothiazinen.3 wurde auch durch Reduktion von 6,7-Dimethoxy-3,4-dimethyl-2H-1,3-benzothiaziniumjodid (5) erhalten. Die Reduktion der quartären Ammoniumsalze9 a–c ergab ebenfalls die Cryptostillin I-, II-, III-(±)-4-thiaanalogen Verbindungen (10 a–c). Reduktion der 4H-1,3-Benzothiazinium-Salze11 a–c lieferte die entsprechenden Isomeren12 a–c der obengenannten Verbindungen.
    Notes: Summary (±)-4-Thiacarnegin (3) was synthesized by reaction of 6,7-dimethoxy-3-methyl-2H-1,3-benzothiazinium iodide (2) with methyl magnesium iodide, thereby opening a new synthetic route to 4-substituted dihydro-2H-1,3-benzothiazines. Compound3 was also obtained by reduction of 6,7-dimethoxy-3,4-dimethyl-2H-1,3-benzothiazinium iodide (5). In a similar way, reduction of the quaternary salts9 a–c afforded the (±)-4-thia analogues of cryptostilin-I, -II and -III (10 a–c). The isomers of the former compounds (12 a–c) were also synthesized by reduction of the 4H-1,3-benzothiazinium salts11 a–c.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 120 (1989), S. 587-590 
    ISSN: 1434-4475
    Keywords: 1,3-Benzothiazines ; Basicity ; Rate of hydrolysis ; Quaternization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Basizität und die Geschwindigkeit der Hydrolyse von 2H- und 4-H-Benzothiazinen (1,2) in saurer Lösung wurde UV/VIS spektroskopisch gemessen. Die Reaktionsgeschwindigkeit der Quarternisierung mit Methyljodid wurde oszillometrisch in geschlossenen Ampullen bestimmt. 4-Aryl-2H-1,3-benzothiazin (2) ist als zyklische Schiffsche Base die stärkere Base, deren Reaktionsgeschwindigkeit mit Methyljodid ungefähr zehnmal größer ist als die des 2-Aryl-4H-1,3-benzothiazin (1);2 ist auch stabiler. Aufgrund dieser Ergebnisse und der unterschiedlichen Wasserlöslichkeit ihrer Hydrochloride konnten die während der Synthese nebeneinander entstehenden Isomeren getrennt werden.
    Notes: Summary The basicities of 2H- and 4H-1,3-benzothiazines (1,2) were measured spectrophotometrically in buffer solutions. The rates of quaternization with methyl iodide were monitored in sealed ampoules by an oscillometric method. The stabilities were determined by measurement of the rate of acidic hydrolysis via changes in the uv/vis spectra. As a cyclic Schiff base, 4-aryl-2H-1,3-benzothiazine (2) is the stronger base, and reacts about ten times faster with methyl iodide; its stability is greater than that of 2-aryl-4H-1,3-benzothiazine (1). On the basis of these results and by means of the different water-solubilities of the hydrochlorides the isomers formed during the synthesis can be separated and purified.
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