Butyl isocyanate → isopropyl 2-[N-(N-butylaminocarbonyl)aminosulfonyl]-4-chlorobenzoate

Participants

Reaction Steps

A mixture of 1063.4 g of isopropyl 2-(aminosulfonyl)-4-chlorobenzoate, 590.4 g of n-butyl isocyanate and 590.4 g of K2CO3 in 10.8 liters of 2-butanone are heated under reflux overnight. After cooling to room temperature, the reaction mixture is in each case poured into 10 liters of ice-water. The aqueous phase is extracted with 9 liters of methylene chloride. The aqueous phase is acidified to pH 1.0 using concentrated HCl, and the resulting precipitate is filtered off. After drying, 714.6 g of isopropyl 2-[N-(N-butylaminocarbonyl)aminosulfonyl]-4-chlorobenzoate (44% of theory) of melting point 129-132° C. are obtained.

Provenance & Evidence