AN IMPROVED PROCESS FOR MANUFACTURE OF 4-BROMO-2-OXYIMINO BUTYRIC ACID AND ITS DERIVATIVES

摘要

A process for producing 4-bromo-2-oxyimino butyric acid, predominantly as the (Z)-isomer of formula (I),wherein R is hydrogen; a linear or branched C1-4 alkyl group; a linear or branched C1-4 alkyl group substituted by a carboxylic acid or an aryl group; a substituted or unsubstituted cyclic alkyl group of 3-6 carbon atoms or a substituted or unsubstituted aryl group. The product is produced by reacting bromine with a 2-(oxyimino)-3-oxo butyric acid derivative of formula (II)wherein R is as defined above and R<1 >is a tert-butyl group in presence of an organic solvent and in presence of a C1-4 alcohol and acetyl bromide at a temperature ranging from about -15° C. to about +15° C. Bromine is used in a proportion of about 0.90 to about 1.35 moles per mole of compound (II), preferably 0.90 to 1.10 moles. The acetyl bromide is used in molar proportions of 0.9 to 2 moles per mole of compound (II), preferably 0.9 to 1.5 moles.