PREPARATION OF 2-SUBSTITUTED 4-CHL0R0-5-F0RMYLIMIDAZ0LES BY VILSMEIER REACTION OF THE CONDENSATION PRODUCT OF GLYCINE AND AN IMIDO ESTER WITH A FORMAMIDE IN THE PRESENCE OF A TRIFLATE (TRIFLUORMETHAN?SULPHONATE) CATALYST

摘要

The invention relates to process for the preparation of a 2-substituted 4-chloro-5-formylimidazole of the formula (I), in which R is hydrogen, alkyl, alkenyl, cycloalkyl, arylalkyl or aryl, wherein glycine is reacted with an imido ester of the formula (II), in which R has the meaning recited above, and RSUB1/SUB is alkyl, to give a compound of the formula (III), which is then subjected to a Vilsmeier reaction using a chlorinating agent and a formamide of the formula (IV), in which R8 and R3 are identical or different and each is a (CSUB1/SUB-CSUB4/SUB) alkyl, wherein said Vilsmeier reaction is performed in the presence of a triflate catalyst.