| 摘要 |
Provided is a process for the preparation of weinreb amide derivatives, which produces no by-products and shows excellent reliability and reproductivity, thereby not causing the environmental problems as well as reducing the cost in production. The weinreb amide derivatives represented by the formula I, is prepared by the process comprising the step of reacting a carboxylic acid derivative represented by the formula II with N,O-dimethylhydroxylamine in the presence of a triphosgene. In the formulae, R represents hydrogen, an alkyl or substituted alkyl group having carbon atoms of from 1 to 20, or an aryl group or substituted aryl group. The triphosgene is employed in a mole ratio of from 0.33 to 1.00, based on the carboxylic acid derivative. Particularly, the reaction is carried out at a temperature of 0 to 45 deg.C.
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