| 摘要 |
PROBLEM TO BE SOLVED: To obtain a 4-difluorohalogenoalkyl-3-substituted pyridine derivative that is useful as a herbicide and plant growth regulator, and has high herbicidal or plant growth regulating effects at its small quantity of application. SOLUTION: This 4-difluorohalogenoalkyl-3-substituted pyridine derivative of formula I (X is Cl, Br, etc.; R1 is a 1-8C alkyl, etc.; provided, however, that when the derivative contains optical isomers, diastereomers or geometric isomers, the derivative of formula I embraces both of a mixture of respective isomers and isolated isomers), for example, 4-difluorochloromethyl-3-(4- chlorobenzoyl)pyridine, is obtained, for example, by condensingβ-acylvinyl ether of formula II (R' is a 1-4C alkyl) obtained by acylating a vinyl ether and a compound of formula III obtained fromβ-acylvinyl ether via a hydroxyvinyl ketone in the presence of a base, and then subjecting the condensate to a dehydrating cyclic reaction.
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