Phosgene → HCID 20134769, compound

Participants

Reaction Steps

Methyl N-(2-ethoxy-3-chloro-5-aminophenyl)carbamate (2.67 g) in toluene (20 ml) was dropwise added to an ethyl acetate solution containing 10 g of phosgene at 10° to 20° C. The resultant 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 methyl N-(2-ethoxy-3-chloro-5-isocyanatophenyl)carbamate. The thus obtained crude substance was added to a toluene solution (50 ml) containing triethylamine (1.0 g) and 3-buten-2-ol (0.79 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 silica gel chromatography using a mixture of toluene and ethyl acetate as the eluent to give 1-methyl-2-propenyl N-(3-chloro-4-ethoxy-5-methoxycarbonylaminophenyl)carbamate (Compound No. 3) (3.57 g) in a yield of 95.6 %. nD25.0 1.5383.

Provenance & Evidence