| 摘要 |
The invention relates to a novel process for the preparation of compounds of formula I wherein R1 is hydrogen or a suitable amino-protecting group, R2 is unsubstituted or substituted alkyl, R3 is hydrogen, aryl, heterocyclyl, unsubstituted or substituted alkyl or unsubstituted or substituted cycloalkyl, R4, independently of R1, is hydrogen or a suitable amino-protecting group and m is a number from 1 to 7; and wherein further suitable protecting groups for functional groups may be present; which compounds are antivirally active or can be used as starting materials for pharmaceutically active, especially antiviral compounds. The precursor is an oxo compound, which is in turn prepared by hydrogenation with a suitable complex hydride or with hydrogen in the presence of a suitable catalyst and acyl migration starting from a hydrazone, which is in turn preferably prepared from a nitrile via an imino compound by means of hydrogenation and reaction with a hydrazine derivative, which is prepared from an aldehyde by reaction with a reactive derivative of a carboxylic acid in the presence of a cyanide salt; and the novel intermediates required therefor. |
