| 摘要 |
<p>A process for the preparation of 4-substituted benzopyran derivatives which comprises preparing N-(2-cyanoethyl)-5-fluoro-4-fluoromethyl-4-(4-trifluoromethylphenoxy)-2-pentynamide from 1-fluoro-2-fluoromethyl-3-butyn-2-yl 4-trifluoromethylphenyl ether and cyclizing this pentynamide derivative into 2,2-bis(fluoromethyl)-N-(2-cyanoethyl)-6-trifluoromethyl-2H-1-benzopyran-4-carboxamide; and other processes therefor. The processes make it possible to prepare the benzopyran derivatives in a shortened process time as compared with those of the prior art with high safety through easy purification.</p> |
