| 摘要 |
Benzyl cyanoacetals of formula: <IMAGE> wherein R1, R2 and R3 are the same or different and each is a halogen or a hydrogen atom, an alkoxy group, an alkyl group, or a dialkylamino group; R4 is an alkoxycarbonyl group, or an aldehyde group; AND R5 is an alkyl group; the alkyl or alkoxy groups each having from 1 to 4 carbon atoms, and their use as intermediates in the preparation of antibacterial 2,4-diamino-5-benzylpyrimidines. They are prepared from a reaction between an orthoester and an alpha -substituted- beta -benzylpropionitrile and then the resulting cyanoacetal is converted to the benzyl-pyrimidine by reaction with guanidine. |
