Phosgene → 1-Isocyanato-3,5-dimethoxybenzene

Participants

Reaction Steps

A mixture of 3,5-dimethoxyaniline (1.5 g) in toluene (20 ml) was dropwise added to a toluene solution containing 10 g of phosgene at 10° to 20° C. The resulting mixture was gradually heated and, after being refluxed for 30 minutes, cooled to room temperature. The solvent was removed by distillation under reduced pressure to give 3,5-dimethoxyphenyl isocyanate (1.7 g). The thus obtained crude substance was added to a toluene solution (50 ml) containing triethylamine (1 g) and propargyl alcohol (2 g). The resultant mixture was allowed to stand at room temperature for 12 hours, poured into ice-water and extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by recrystallization from toluene to give propargyl N-(3,5-dimethoxyphenyl)carbamate (1.7 g) in a yield of 75 % (calculated from the starting 3,5-dimethoxyaniline). M.P., 139.5°-140.5° C.

Provenance & Evidence