Process for preparing carboxylic acid derivative

摘要

PCT No. PCT/JP95/02673 Sec. 371 Date Aug. 22, 1996 Sec. 102(e) Date Aug. 22, 1996 PCT Filed Dec. 25, 1995 PCT Pub. No. WO96/20188 PCT Pub. Date Jul. 4, 1996There is described a process for preparing 3-(2-thienylthio)butyric acid by converting a compound having the formula (III): <IMAGE> (III) wherein R is a straight chain or branched C1 to C4 alkyl group, whereby the production of 3-(3-thienylthio)butyric acid as a by-product which is the position isomer can be controlled to at most 0.1 mol %. 3-(2-Thienylthio)butyric acid is a useful compound as an intermediate for a medicinal compound.