PROCESS FOR PRODUCING 4-TRIFLUOROMETHYLNICOTINIC ACID

摘要

A process for producing 4-trifluoromethylnicotinic acid of the formula (VIII) or its salt: (see formula I) which comprises (i) a first step of reacting a halide of the formula (I): CF3COHal (I) wherein Hal is a halogen atom, with a compound of the formula (II): CH2=CHOR1 (II) wherein R1 is an alkyl group, in the presence of a base to obtain a 4-alkoxy-1,1,1-trifluoro-3-buten-2-one of the formula (III): CF3CO-CH=CH-OR1 (III) wherein R1 is as defined above, and reacting this compound with ammonia to obtain 4-amino-1,1,1-trifluoro- 3-buten-2-one of the formula (IV): <IMG> and (ii) a second step of subjecting the 4-amino-1,1,1- trifluoro-3-buten-2-one obtained in the first step and a compound of the formula (V): ACO2R2 (V) wherein R2 is an ester-forming residue, and A is (R3O)CH=CH- or (R30)2CHCH2-, wherein R3 is an alkyl group, to a condensation reaction to obtain a compound of the formula (VI) (inclusive of its salt): <IMG> wherein R2 is as defined above, and/or a compound of the formula (VII) (inclusive of its salt): <IMG> wherein R2 and R3 are as defined above, as the reaction product, and then subjecting the reaction product to ring closure and hydrolysis.