Carbon Dioxide → 2-Chloro-4-fluoro-5-isothiocyanatothiobenzoic acid (methoxycarbonylmethyl) ester

Participants

Reaction Steps

A solution of 3.8 g of the resulting 5-amino-2-chloro-4-fluorothiobenzoic acid (methoxycarbonylmethyl) ester in 100 ml of dichloromethane is added dropwise at from 25° to 30° C. to a suspension of 6 g of calcium carbonate, 4 ml of thiophosgene, 20 ml of dichloromethane and 20 ml of water. When the evolution of carbon dioxide has ceased, the batch is stirred for a further 18 hours at room temperature. After filtering and washing with water, the organic phase is separated off, dried over sodium sulfate and then concentrated by evaporation to yield 4.8 g of 2-chloro-4-fluoro-5-isothiocyanatothiobenzoic acid (methoxycarbonylmethyl) ester in the form of an oil which is used without further purification in the next reaction step.

Provenance & Evidence