ETHYL 2-(2,3-DICHLOROPHENYL)-1,3-THIAZOLE-4-CARBOXYLATE synthesis

Yield:-

Reaction Conditions:

Stage #1: 2-(2,3-dichloro-phenyl)-thiazole-4-carboxylic acid ethyl esterwith methanol;lithium hydroxide;water for 4 h;Heating / reflux;
Stage #2: with hydrogenchloride in water; pH=2;Product distribution / selectivity;

Steps:

B.1

Step 1. Ester Hydrolysis; To a solution of 2-(2,3-dichloro-phenyl)-thiazole-4-carboxylic acid ethyl ester (Maybridge plc, Tintagel, Cornwall, UK; 20 g, 66.2 mmol) in MeOH (100 mL) and water (100 mL) was added LiOH (1.7 g. 72.8 mmol). After stirring for 4 h at reflux temperature, MeOH was evaporated in vacuo. To the residue was added more water, and the solution was acidified to pH 2 with concentrated HCl (7 mL), and extracted with EtOAc. The combined extracts were evaporated to give product which was used without further purification.

References:

US2007/167622,2007,A1 Location in patent:Page/Page column 12