PROCESS FOR PREPARING 3-BROMO-4-FLUORO-BENZALDEHYDE ACETALS, INTERMEDIATES AND THEIR PREPARATION

摘要

A process for the preparation of a 3-bromo-4-fluoro-benzaldehyde acetal of the formula: in which R each independently is a C1 to C4 alkyl group or the radicals R together are a C2 to C5 alkanediyl radical, comprising reacting 3-bromo-4-fluoro-phenylglyoxylic acid of the formula: with an amine of the formula: H2N-R1 in which R1 is an alkyl, cycloalkyl or aryl radical, at a temperature between about 0 DEG and 200 DEG C. to produce a 3-bromo-4-fluoro-benzaldimine of the formula: and reacting that with an alcohol or alkanediol of the formula: (HO)n-R in which n is 1 or 2 in the presence of sulphuric acid at a temperature between about 0 DEG and 100 DEG C. Various of the reactants are new and syntheses are given.