SYNTHESIS OF 5-CHLORO-2-[(3,4,4-TRIFLUORO-3-BUTEN-1-YL)THIO]-THIAZOL

Abstract

The present invention provides an improved process for preparing 5-chloro-2-[(3,4,4-trifluoro-3-buten-1-yl)thio]thiazole comprising reacting 2-[(3,4,4-trifluoro-3-buten-1-yl)thio]thiazole with N-chlorosuccinimide (NCS) in the presence of water, the improvement comprising performing the step of reacting the compound of formula (II) with NCS in the presence of a reduced amount of water. The method for increasing the yield of the compound of formula (I) comprises reacting a compound of formula (II) with N-chlorosuccinimide (NCS), wherein the reaction mixture has a water content of between 2% and 7% by weight relative to the weight of NCS in the reaction mixture, and wherein the molar ratio of NCS to the compound of formula (II) increases as the concentration of water in the reaction mixture increases.