Zobrazeno 1 - 10
of 18
pro vyhledávání: '"Rüdiger Ozegowski"'
Publikováno v:
Liebigs Annalen. 1996:1443-1448
The enzyme-catalyzed regio- and enantioselective alcoholysis of racemic cis- and trans-2,3-dimethylpentanedioc anhydride in the presence of Novozym 435 from Candida antarctica afforded two of the eight possible monoesters with an enantiomeric excess
Autor:
Rüdiger Ozegowski, Helmut Dorn
Publikováno v:
Journal f�r Praktische Chemie/Chemiker-Zeitung. 340:437-449
1-Substituted 3-hydroxy-1H-pyrazoles 1 react with chloroform, NaOH, and aceton resp. butan-2-one O-regiospecifically to yield 2-methyl-2-[(1H-pyrazol-3-yl)oxy]-propanoic resp. -butanoic acids 14via a dichlorocarbene (12)–dichlorooxirane (9) pathway
Publikováno v:
Liebigs Annalen. 1995:1699-1702
The preparation of enantiomerically pure 1-(2-methylpropyl) 4-hydrogen (S)-2-methylbutanedioate (ent-3) by an enzyme-catalyzed sequential esterification of (±)-2-methylbutanedioic anhydride (rac-1) demands two different enzymes. Lipozyme, a lipase f
Publikováno v:
Tetrahedron: Asymmetry. 6:1191-1194
The syn - and anti -relationship of the vicinal methyl groups in the 2,3-dimethylbutanedioic anhydrides 1 and rac- 5 has a significant influence on the lipase-catalyzed enantioselective alcoholysis with 2-methylpropanol. For their conversion into the
Publikováno v:
Liebigs Annalen der Chemie. 1994:1019-1023
The enzyme-catalyzed sequential esterification of (±)-2-methylpentanedioic anhydride (rac-1) with 2-methylpropanol in diethyl ether afforded a 1:1 mixture of 1-(2-methylpropyl) 5-hydrogen (S)-4-methylpentanedioate (ent-2) with an enantiomeric excess
Publikováno v:
Liebigs Annalen der Chemie. 1993:805-808
The influence of several enzymes, alcohols, and solvents on the stereochemical outcome of the asymmetric alcoholysis of 3-substituted pentanedioic anhydrides was investigated. The alcoholysis of 3-acetoxypentanedioic anhydride (5a) in diethyl ether w
Publikováno v:
Tetrahedron: Asymmetry. 4:695-698
1-(2-Methylpropyl) 5-hydrogen (2 R ,4 S )-2,4-dimethylpentanedioate with an enantiomeric excess of 90 % was obtained in a yield of 72 % from meso -2,4-dimethylpentanedioic anhydride and 2-methylpropanol by an asymmetric alcoholysis catalyzed by the l
Autor:
Rüdiger Ozegowski, Helmut Dorn
Publikováno v:
ChemInform. 29
1-Substituted 3-hydroxy-1H-pyrazoles 1 react with chloroform, NaOH, and aceton resp. butan-2-one O-regiospecifically to yield 2-methyl-2-[(1H-pyrazol-3-yl)oxy]-propanoic resp. -butanoic acids 14via a dichlorocarbene (12)–dichlorooxirane (9) pathway
Publikováno v:
Liebigs Annalen der Chemie. 1994:215-217
(±)-anti-2,4-Dimethylpentanedioic anhydride (rac-1) was converted in good yields and with high enantiomeric excess by an enzyme-catalyzed sequential esterification into the (2R,4R)-monoester 2 and the (2S,4S)-diester ent-3. Best results were obtaine
Autor:
Rüdiger Ozegowski, Helmut Dorn
Publikováno v:
Zeitschrift für Chemie. 22:134-135