| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject new compound exhibiting excellent herbicidal effect and dwarf effect and useful as a herbicide and a plant growth regulator. SOLUTION: This derivative is a compound expressed by the formula (X is Cl, Br or I; R1 and R2 are independently H, a 1-8C alkyl, a 3-8C alkenyl, a 3-8C alkynyl, a 3-8C cycloalkyl or cyanomethyl), e.g. 4-chloro-4,4-difluoro-2 ethoxymethylene-3-oxobutanoic acid ethyl ester. The compound of the formula is obtained by reacting, e. g. aβ-ketoacid ester with an orthoformic acid ester to afford anα-alkoxymethylene-β-ketoacid ester, then reacting theβ-ketoacid ester with orthoformamidines to give a 4-haloalkyl-substituted pyridine-5- carboxylic acid ester, hydrolyzing the carboxylic acid ester and converting the hydrolyzed product into an acid chloride with a chlorinating agent and condensing the acid chloride with an amine derivative under basic conditions.
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