NOVEL KETOESTER AND ITS PRODUCTION

摘要

NEW MATERIAL:A ketoester expressed by formula I (R<1> and R<2> are alkyl, alkenyl, cycloalkyl or aralkyl or acetal type protecting groups capable of together forming alkylene; R<3> to R<5> are H, alkyl, alkenyl, aryl, cycloalkyl or aralkyl). EXAMPLE:Methyl 5-(dimethoxymethyl)-3-methoxycarbonyl-2-oxaheptanate. USE:An intermediate of 2-(2-imidazolin-2-yl)pyridines useful as herbicides, capable of readily producing them inexpensively and readily from an easily obtainable raw material in high yield. PREPARATION:A compound expressed by formula II is reacted with a compound expressed by formula III (R<6> is each group in R<5>) in the presence of a base to provide the compound expressed by formula I. The above-mentioned herbicides expressed by formula IV can be readily produced in high yield from the compound I through compounds expressed by formula V to formula VI.