A. Ayi, R. Guedj, B. Septe
Aug 1, 1995
Citations
0
Influential Citations
13
Citations
Journal
Journal of Fluorine Chemistry
Abstract
Abstract The hydrolysis of methyl d,l -3,3-difluorophenyl alanate (1a) and methyl d,l -3,3-difluoro-2-aminobutanoate (1b) and their N-acetyl derivatives 2a and 2b by subtilisin has been studied. All derivatives examined were enzymatically resolved to separable mixtures of the corresponding 3,3-difluoro- l -amino acids (3a and 3b) or N-acetylamino acids (5a and 5b) and the unchanged 3,3-difluoro d -amino esters (4a and 4b) or N-acetylamino esters (6a and 6b). Acidic hydrolysis of methyl 3,3-difluoro- d -phenyl alanate (4a) or its N-acetyl derivative 6a led to 3,3-difluoro- d -phenyl alanime (8a). In the same manner, l - and d -2-amino-3,3-difluorobutanoic acids 7b and 8b were prepared starting from 5b and 6b. Optical purity and enantiomeric excess were determined by GC analysis of the N-acetyl esters and by NMR analysis determined in the presence of Eu(tfc)3. By these methods, unchanged methyl 3,3-difluoro- d -amino ester derivatives showed an ee of ≥ 90% while l -amino acids were estimated to have ≥ 95% ee.