| 摘要 |
<p>PURPOSE:To suppress formation of by-products and readily obtain the subject compounds useful as a raw material for medicines, agricultural chemicals, etc., in high purity and yield within a short time by reacting thiazolecarboxylic acids with triphosgene. CONSTITUTION:A compound expressed by formula I (R1 is 1-6C alkyl, etc.; R2 is H, 1-6C alkyl, etc.) is reacted with triphosgene in the presence or absence of a catalyst (e.g. N,N-dimethylformamide), preferably in a solvent (e.g. toluene) at a temperature from ambient temperature to the boiling point temperature of the solvent to afford the objective compounds expressed by formula II. The reaction is carried out by using 0.35-5.0mol triphosgene, 0.8-4 l solvent and 0.1-5wt.% catalyst based on 1mol compound expressed by formula I. 2- Methylthiazole-5-carboxylic acid is exemplified as the compound expressed by formula I.</p> |
