ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Enzym-katalysierte Reaktionen, 13. Eine neue, effiziente Synthese von Fagomin (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 1211-1212 
    Details
    ISSN: 0170-2041
    Keywords: Fagomine ; Enzymes ; Transketolase ; Carbohydrates ; Yeast transketolase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzyme-Catalyzed Reactions, 13.  -  A New, Efficient Synthesis of Fagomine2-Deoxy-L-threo-5-hexulosonitrile (4) is obtained in excellent chemical yield by yeast transketolase (EC 2.2.1.1)-catalyzed reaction of racemic 3-hydroxy-4-oxobutyronitrile [(R/S)-2] with lithium hydroxypyruvate (3). Catalytic hydrogenation of 4 exclusively gives fagomine (7).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Aminosäuren, 16. Darstellung von N-Acyl-2,3-didehydro-2-aminocarbonsäureestern (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1295-1301 
    Details
    ISSN: 0170-2041
    Keywords: 2-Azidocarboxylates ; Rhenium catalysts ; Amino acids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino Acids, 16. - Synthesis of N-Acyl-2,3-didehydro-2-amino Acid Esters[2]N-Acyl-2,3-didehydro-2-amino acid esters 3, 5, 7-12, with a great variety of N-substituents, are obtained in good yields by the perrhenate-catalyzed decomposition of methyl 2-azido carboxylates 1 in organic solvents in the presence of the corresponding acyl chlorides 2. By using methyl 2-azidoisovalerate (1a), the conditions (catalyst, solvent, temperature) for the reaction to give 3a were optimized. The reactivity of acyl chlorides can be strongly enhanced with equimolar amounts of dimethyl formamide, which allows a lowering of the decomposition temperature for this reaction. Under these mild reaction conditions also the unstable N-acyldehydroalanine derivative 5f can be obtained in good yield.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301211
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Enzym-katalysierte Reaktionen, 14. Stereoselektive Darstellung von Thiozuckern aus achiralen Vorstufen mittels Enzymen (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 1297-1301 
    Details
    ISSN: 0170-2041
    Keywords: 5-Thiopentulofuranose ; 6-Thiohexulopyranose ; Rabbit muscle aldolase (RAMA) ; Yeast transketolase ; Carbohydrates ; Enzymes ; Transketolase ; Aldolase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzyme-Catalyzed Reactions, 14.  -  Stereoselective Synthesis of Thiosugars from Achiral Starting Compounds by EnzymesA novel synthesis for thiosugars starting from achiral compounds by using enzymes as catalysts is described. 5-Thio-D-threo-2-pentulofuranose (4), for example, is prepared either by the RAMA (rabbit muscle aldolase)-catalyzed reaction of mercaptoacetaldehyde (1b) with dihydroxyacetonephosphate (2) or by the yeast transketolase-catalyzed reaction of 2-hydroxy-3-mercaptopanal (R/S)-6 with lithium 3-hydroxypyruvate (9). 6-Thio-D-arabino-2-hexulopyranose (8a) and 6-thio-L-xylo-2-hexulopyranose (8b) are obtained by the RAMA-catalyzed reaction of racemic (R/S)-6 with 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Enzym-katalysierte Reaktionen, 7. Enantioselektive Veresterung racemischer Cyanhydrine und enantioselektive Hydrolyse oder Umesterung racemischer Cyanhydrinester mittels Lipasen (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 47-54 
    Details
    ISSN: 0170-2041
    Keywords: Cyanohydrins and cyanohydrin esters, optically active ; Resolutions, kinetic enzyme-catalyzed ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzyme-Catalyzed Reactions, 71). - Enantioselective Esterification of Racemic Cyanohydrins and Enantioselective Hydrolysis or Transesterification of Cyanohydrin Esters by LipasesPure cyanohydrin enantiomers (S)-1/(R)-1 and their O-acyl derivatives (R)-3/(S)-3 are obtained from three different lipasecatalyzed reactions: i) enantioselective hydrolysis of aliphatic and aromatic racemic cyanohydrin esters 3, ii) enantioselective acylation of racemic cyanohydrins 1, iii) enantioselective transesterification of 3 with primary alcohols. Both the cyanohydrin esters and the free cyanohydrins (which are prone to racemization) are isolated as enantiomers with high optical purity on a preparative scale. Hydrolysis of the racemic butyrates 3b, e with Candida cylindracea lipase and pseudomonas sp. lipase, respectively, for example, affords the free (S)-cyanohydrins (S)-2-hydroxypentanenitril [(S)-1a] and (S)-mandelonitrile [(S)-1b)] in high yield with 97 and 96% ee, respectively. (S)-1a is obtained with the same optical purity by candida sp. lipase-catalyzed transesterification of 3b with 1-octanol.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199119910108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Enzym-katalysierte Reaktionen, 8. Stereoselektive Darstellung von 2-Aminoalkoholen aus (R)- und (S)-Cyanhydrinen (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 269-273 
    Details
    ISSN: 0170-2041
    Keywords: 2-Amino alcohols ; Cyanohydrins ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzyme-Catalyzed Reactions, 8. - Stereoselective Synthesis of 2-Amino Alcohols from (R)- and (S)-Cyanohydrinserythro-2-Amino alcohols (1R,2S)- and (1S,2R)-4 may be synthesized stereoselectively by addition of Grignard compounds to cyanohydrins (R)-, (S)-1 and their O-trimethylsilyl derivatives 3, respectively, followed by hydrogenation. The threo-2-amino alcohols (1S,2S)- and (1R,2R)-4 are easily accessible by inversion at C-1 of the (1R,2S) and (1S,2R) compounds.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199119910145
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Aminosäuren, 17 - Eine neue Synthese von Didehydrodipeptiden und Didehydrotripeptiden (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1303-1311 
    Details
    ISSN: 0170-2041
    Keywords: 2-Azidocarboxylates ; Rhenium catalysts ; Peptides ; Amino acids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino Acids, 17. - A New Synthesis of Didehydro Dipeptides and Didehydro TripeptidesEsters of N-phthaloyl-protected (R)- or (S)-didehydro dipeptides 5-7 were obtained in good yields by the perrhenate-catalyzed decomposition of 2-azidocarboxylates 1 with N-phthaloyl-protected (R)- or (S)-amino acid chlorides 2 in presence of at least equimolar amounts of N-methyl-2-pyridone (4) as acylation catalyst. Esters of didehydro tripeptides 16 were obtained in a comparable procedure from the optically active amino acid chlorides 2 and 2-(2-azidoacyl)amino acid esters 15, which were prepared from 2-azidocarboxylic acids 12 or the corresponding chlorides 13 with 2-amino acid ester hydrochlorides (S)-14. - As an example, the unprotected (S)-alanly-didehydrovalin 20 was prepared from the didehydro dipeptide 18a without any racemization by hydrolysis of the benzyl ester and subsequent hydrogenolytic removal of the N-phthaloyl group.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301212
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Aminosäuren, 18. Darstellung und Reaktionen von 2-Isocyanato-2-alkensäureestern (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 1069-1074 
    Details
    ISSN: 0170-2041
    Keywords: 2-Azidocarboxylates ; Rhenium catalyst ; 2-Isocyanato-2-alkenoates ; Amino acids ; Alkenoates ; Diels-Alder reactions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino Acids, 18. - Preparation and Reactions of 2-Isocyanato-2-alkenoates2-Isocyanato-2-alkenoates 3 were obtained in good yields by the perrhenate-catalyzed decomposition of 2-azidoalkanoates 1 in the presence of diphosgene (2a) or phosgene (2b). Methyl 2-azidopropionate (1h) reacts to give a mixture of methyl 2-isocyanato-2-propenoate (3h) and methyl 2-chloro-2-isocyanatopropionate (4). The addition product 4 could easily be converted into 3h by elimination of HCl with triethylamine at 0°C. With benzyl alcohol (5a) and tert-butyl alcohol (5b) the isocyanates 3 react smoothly to give the corresponding Z- or Boc-protected 2,3-didehydroamino acid esters 6 and 7, respectively. The acrylic acid derivative 3h reacts as dienophile with various dienes to yield the Diels-Alder adducts 8-10.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419941105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...