Hydrochloric Acid → HCID 135838380, compound

Participants

Reaction Steps

To a solution of 4-hydroxy-2-methyl-3-(5-tetrazolyl)-2H-1,2-benzothiazine 1,1-dioxide hemihydrate (18.0 g) and potassium carbonate (4.32 g), in N,N-dimethylformamide (63 ml) was added benzylbromide (7.81 ml). After being stirred for 16 hours at room temperature, the mixture was poured into 1N HCl (500 ml) with stirring. The resulting solids were filtered off and washed with water (100 ml) and then with petroleum ether (50 ml). The wet solids were recrystallized from toluene (150 ml) to give 4-hydroxy-3-[(2-benzyl)tetrazol-5-yl]-2-methyl-1,2-benzothiazine 1,1-dioxide (16.70 g). The mother liquor contains the said compound and its 1-benzyl isomer. It was concentrated to an oil (6.03 g), which was treated with acetic anhydride (30 ml) at 110° C. for 1.5 hours, concentrated and crystallized in toluene (30 ml), to afford 4-acetoxy-3-[(2-benzyl)-tetrazol-5-yl]-2-methyl-1,2-benzothiazine 1,1-dioxide (1.31 g). The resulting mother liquor was concentrated to a viscous oil, diluted with toluene (10 ml) and seeded. The resulting crystals were filtered off and recrystallized from toluene (24 ml) to give 4-acetoxy-[(1-benzyl)tetrazol-5-yl]-2-methyl-1,2-benzothiazine 1,1-dioxide (0.602 g).

Provenance & Evidence