Thiophosgene → 2,4-Dichloro-6-fluoro-7-isothiocyanatobenzothiazole

Participants

Reaction Steps

A suspension of 16.9 g calcium carbonate in 100 ml water was added to a solution of 19.4 g thiophosgene in 100 ml dichloromethane. A solution of 40 g 7-amino-2,4-dichloro-6-fluorobenzothiazole in 500 ml dichloromethane was added, dropwise at 5° C., and the mixture stirred for 8 hours at room temperature. The solid was filtered, the phases were separated, and the organic phase dried over magnesium sulfate and concentrated. The residue was purified by column chromatography (eluent: hexane/ethyl acetate). Yield: 16 g=38% of theory m.p.: 80°-81° C.

Provenance & Evidence