Lipase-catalyzed enantioselective transesterification toward esters of 2-bromo-tolylacetic acids
摘要:
Lipases from Candida antarctica, Pseudomonas cepacia and Rhizomucor miehei were tested in the resolution of seven racemic substrates belonging to the (RS)-2-bromo tolyl acetate ester category, but differing either in the position of the methyl substituent on the acyl part of the aromatic ring, or in the structure of the alkyl group. Lipase-catalyzed kinetic resolution via transesterification reaction between the ester and octanol in octane revealed that, of the three enzymes tested, P. cepacia lipase is the most efficient for resolution of the various racemates, with R-enantiopreference. In addition, the position of the methyl substituent was found to play a key role in governing the enantioselectivity of the reaction. Using P. cepacia lipase and 2-bromo-in/p-tolyl- or 2-bromophenylacetic acid esters E-values of >50 were measured, whereas with the ortho derivatives, E-values dramatically decreased to <6. (C) 2003 Elsevier Science Ltd. All rights reserved.
The invention relates to novel phenyl-substituted cyclic ketoenols of the formula (I)
1
in which
Het represents one of the groups
2
in which A, B, D, G, X and Z are each as defined in the description, to a plurality of processes and intermediates for their preparation, and to their use as pesticides.
本发明涉及式 (I) 的新型苯基取代环酮烯醇
1
其中
Het 代表以下基团之一
2
其中 A、B、D、G、X 和 Z 各如描述中所定义,本发明涉及制备它们的多种工艺和中间体,以及它们作为杀虫剂的用途。
Electrostatic participation by carboxylate groups in forming .alpha.-lactones