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

Participants

Reaction Steps

A solution of 3.8 g of the 5-amino-2-chloro-4-fluoro-thiolbenzoic acid (methoxycarbonylmethyl) ester obtained in accordance with Example P2 in 100 ml of dichloromethane is added dropwise at 25°-30° C. to a suspension of 6 g of calcium carbonate, 4 ml of thiophosgene, 20 ml of dichloromethane and 20 ml of water. After the evolution of carbon dioxide has ceased, the mixture is stirred for 18 hours at room temperature. After filtration and washing with water, the organic phase is separated off, dried over sodium sulfate and then concentrated by evaporation, yielding 4.8 g of 2-chloro-4-fluoro-5-isothiocyanato-thiolbenzoic acid (methoxycarbonylmethyl) ester in the form of an oil which is used in the next reaction step without further purification.

Provenance & Evidence