Benzene → 1-tert-butoxycarbonyloxy-6-chloro-1H-benzotriazole

Participants

Reaction Steps

A solution of phosgene (5g.) in benzene (23.5 ml.) was added dropwise under ice-cooling to a suspension of 1-hydroxy-6-chloro-1H-benzotriazole (8.5 g.) and pyridine (3.9 g.) in benzene (50 ml.). The mixture was stirred for 30 minutes at the same temperature and allowed to stand overnight. A solution of tert-butyl alcohol (3.7 g.) and pyridine (4.0 g.) in benzene (50 ml.) was added dropwise for 20 minutes under ice-cooling to the resultant solution containing 1-chlorocarbonyloxy-6-chloro-1H-benzotriazole. The resultant mixture was stirred for 2 hours at the same temperature and allowed to stand overnight. The reaction mixture was filtered and the filtrate was concentrated. Ether and petroleum ether were added to the residue to pulverize the residue and the resultant crystals were collected by filtration to give 1-tert-butoxycarbonyloxy-6-chloro-1H-benzotriazole (5.3 g.). The mother liquor was concentrated to give the same desired compound (0.6 g.). Both quantities of crystals were mixed and dissolved in benzene. The resultant solution was then washed with a sodium bicarbonate aqueous solution and water and then dried. The solvent was removed by distillation to give the desired compound (3.2 g.), powder, mp 98° to 100° C (dec.).

Provenance & Evidence