Phosgene → 2-Chloro-6-(4-isocyanatophenoxy)pyridine

Participants

Reaction Steps

A stream of phosgene was passed into 120 ml. of dry toluene maintained at a temperature of about 0° to about 5° C. until a weight of 13.4 grams (0.135 mole) had been absorbed. 4-((6-Chloro-2-pyridinyl)oxy)benzenamine (10.0 grams; 0.045 mole) in 100 ml. of dry toluene was then added to the stirred phosgene solution over a period of about 15 minutes while maintaining the reaction temperature within a range of about 2 to about 5° C. Following the completion of the addition, the reaction mixture was stirred for about 20 minutes and the reaction temperature then gradually raised as excess phosgene was purged with a stream of nitrogen. When a reaction temperature of about 85° C. was attained, the reaction mixture became clear. The toluene solvent was then substantially removed under reduced pressure and hexane added to the residue to give the desired 4-((6-chloro-2-pyridinyl)oxy)phenyl isocyanate product as a white crystalline product having a melting point of 96°-97° C.

Provenance & Evidence