Phosgene → 2-Isocyanato-5-thiomorpholin-4-yl-4-trifluoromethyl-benzoic acid methyl ester

Participants

Reaction Steps

To a suspension of 100 mg (0.312 mmol) of 2-amino-5-thiomorpholin-4-yl-4-trifluoromethyl-benzoic acid methyl ester in 2 ml of dry toluene 1.5 ml of a 20% solution of phosgene in toluene are added at 0° C. After warming to room temperature, a stream of phosgene is introduced into the suspension and simultaneously heating is started. At reflux, the stream of phosgene is maintained for two hours, then replaced by a stream of argon for an additional hour. The toluene is distilled off leaving 126 mg (>100%) of 2-isocyanato-5-thiomorpholin-4-yl-4-trifluoromethyl-benzoic acid methyl ester as a brown solid, sufficiently pure for the next step. 1H-NMR (CDCl3, 360 MHz): 2.75-2.80 (m, 2H); 3.15-3.20 (m, 2H); 4.00 (s, 3H); 7.40 (s, 1H); 7.95 (s, 1H).

Provenance & Evidence