关键词: 生物催化, 蚯蚓粗提物, 华法林, Michael加成

This article describes the synthesis of warfarin and its derivatives by using the crude earthwarm extract as a biocatalyst. Warfarin, an effective anticogulant being used for half a century, has enormous clinic and commercial value. Warfarin and its derivatives are usually prepared through chemical catalysis while biocatalysis was rarely explored. Because biocatalysis is green, sustainable and usually under mild conditions, it is necessary to develop biocatalytic methods for these compounds. It is found that the crude extract of earthwarms is a fine biocatalyst. Earthwarms are harmless and abundant in nature. There are many hydrolases in the alimentary tract of earthwarms, and among of them, proteases are most thoroughly studied. The crude earthwarm extract from Eisenia foetida was prepared, and it was used as a cheap and ecologically friendly biocatalyst for the synthesis of warfarin and its derivatives. The procedure is simple and no additional cofactors and equipments are required. The best results were obtained using l00 mg of earthworm extract in DMSO/water (10% water, V/V) with 1:3 molar ratio of 4-hydroxycoumarin to benzylideneacetone at 50 ℃ for 48 h. Warfarin was obtained in an excellent yield of 98%, and its derivatives were achieved in yields of 57%~99% with some enantioselectivities (up to 20% ee). In addition, control experiments demonstrated that enzyme(s) in the crude extract of earthwarms catalyzed Michael addition reaction. This work provides an alternative method for the synthesis of warfarin and its derivatives by using an easily available natural catalyst.

Key words: biocatalysis, the crude extract of earthworms, warfarin, Michael reaction