Phosgene → HCID 12805022, compound

Participants

Reaction Steps

5.0 g (69.3 millimoles) of cyclobutanol, dissolved in 80 ml of absolute ether, are added dropwise to a stirred solution of 11.5 g (116.3 millimoles) of phosgene in 100 ml of absolute ether at 10°-15° C. The reaction solution is then stirred for 3 hours at room temperature. Thereafter, the excess phosgene is removed by means of a dry stream of nitrogen, and the ether is then removed under reduced pressure at room temperature. The cyclobutyl chloroformate which remains in mixed with 6.0 g (29.5 millimoles) of 6-(p-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone and 180 ml of absolute tetrahydrofuran and the mixture is kept for 20 hours at room temperature and then for 4 hours at 40°-45° C. The product is filtered off at 10° C., washed first with tetrahydrofuran and then with water, and recrystallized from dimethylformamide/water. 2.8 g (31% of theory) of 6-(p-cyclobutoxycarbonylaminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone are obtained as colorless crystals, of melting point 245°-246° C.

Provenance & Evidence