| 摘要 |
A method of preparing a compound of formula (I) where R<1>, R<2>, R<3>, R<4> and R<5> are independently selected from hydrogen or specified substitutents, X is -O-, -S-, -NR<7>-, -C=N-, -C=N-O-, -NR<8>-NR<9>-, where R<7>, R<8> and R<9> are independently selected from hydrogen or alkyl; and R<6> is an alkyl; which process comprises reacting a compound of formula (II) with a compound of formula (III) where R<6> is as defined in relation to formula (I) and Y is a leaving group other than a group SR<x> where R<x> is CH2COOH or C1-4alkyl. Compounds of formula (III) are suitably prepared in situ by a method which forms a further aspect of the invention. |
