Phosgene → 1-chloro-N-(2-chloro-4-fluoro-5-isocyanatophenyl)methanesulfonamide

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 218 g (2.2 mole) of phosgene in 0.6 L of methyl isobutyl ketone at 0° C. was added 546.2 g (2 mol) of N-(5-amino-2-chloro-4-fluorophenyl)-1-chloromethanesulfonamide dissolved in 2 L of methyl isobutyl ketone. During the addition (75 minutes) the temperature was kept between −3° C. and 3° C. The temperature of the solution was raised to 35° C. and 1 L of the solvent was distilled off under reduced pressure (11.0-11.5 kPa (110-115 mbar), maximum temperature: 60° C.). This isocyanate solution was used in the next step without further purification.

Provenance & Evidence