反应详情

By the method of Example 2, 1H-tetrazole-5-acetic acid is reacted with 5,6-diamino-1-[2-(4-nitrophenyl)ethyl]-3-propyluracil (6) to yield 3-[2-(4-nitrophenyl)ethyl]-1-propyl-8-[(1H-tetrazol-5-yl)methyl]xanthine. By the method of Example 3, this substance is alkylated with a mixture of 1,2-dichloroethane, sodium carbonate, and ethylamine to yield 7-(2-ethylamino)ethyl-3-[2-(4-nitrophenyl)ethyl]-1-propyl-8-[(1H-tetrazol-5-yl)methyl]xanthine. By the method of Example 4,7-(2-ethylamino)ethyl-3-[2-(4-nitrophenyl)ethyl]-1-propyl-8-[(1H-tetrazol-5-yl)methyl]xanthine is reduced with hydrazine hydrate or hydrogen gas in the presence of a palladium catalyst to yield 3-[2-(4-aminophenyl)ethyl]-7-(2-ethylamino)ethyl-1-propyl-8-[(1H-tetrazol-5-yl)methyl]xanthine free base. The corresponding hydrochloride salt is then made on exposure to an excess of hydrogen chloride in solution.