反应详情

A solution of 6,7-diamino-3,4-dihydro-2,2-dimethyl-trans-4-piperidino-2H-benzo[b]pyran-3-ol (0.12 g) in 5N-hydrochloric acid (10 ml) was treated with a 12.5% solution of phosgene in toluene (20 ml) and the mixture was stirred at room temperature for 45 minutes. A vigorous stream of nitrogen was then passed through the mixture for 10 minutes, and the solution was evaporated to dryness in vacuo. The residue was recrystallised from ethanol-ether to give the hygroscopic 3,6,7,8-tetrahydro-trans-7-hydroxy-6,6-dimethyl-8-piperidino-pyrano[2,3-f]benzimidazole-2 (1H)-one hydrochloride (1) (0.067 g) mp 177°-180° C.

1. waitA vigorous stream of nitrogen was then passed through the mixture for 10 minutes
2. customthe solution was evaporated to dryness in vacuo
3. customThe residue was recrystallised from ethanol-ether