Phosgene → 6-Isocyanato-2,3-dihydro-1,4-benzodioxine

Participants

Reaction Steps

A mixture of 1,4-benzodioxan-6-amine (300 mg; 2.0 mmol) in toluene (20 ml) and phosgene (10 ml 20% in toluene; 19 mmol) was refluxed for 6 h. The solvent was removed under reduced pressure to give crude 3,4-ethylenedioxyphenylisocyanate. The crude product was added 3-[4-(4-chlorophenyl)-1-piperazinyl]propanol (500 mg; 2.0 mmol) in toluene (10 ml) and refluxed for 16 h. The reaction mixture was then concentrated and submitted to flash chromatography on silica gel 60 eluting with toluene graduated to toluene/ethyl acetate (1:1). The product was taken up in ethyl acetate, which was treated with hydrogen chloride in ether. Recrystallization from methanol/ether afforded 440 mg of the title compound. M.p. 243°-244° C. MS (70 eV): m/z 431 (31%, M+), 254 (34), 209 (100), 177 (75), 121 (31), 70 (38).

Provenance & Evidence