反应详情

By methods well known in the art 3-dimethylaminopropyl isocyanate is converted into 8-benzyl-3-[2-(4-nitrophenyl)ethyl]-1-(3-dimethylaminopropyl)xanthine. By the method of Example 3, this substance is alkylated with a mixture of 1,2-dichloroethane, sodium carbonate and ethylamine to yield 8-benzyl-1-(3-dimethylaminopropyl)-7-(2-ethylamino)ethyl-3-[2-(4-nitrophenyl)ethyl]xanthine. By the method of Example 4 this substance is reduced with hydrazine hydrate or hydrogen gas in the presence of a palladium catalyst to yield 3-[2-(4-aminophenyl)ethyl]-8-benzyl-1-(3-dimethylaminopropyl)-7-(2-ethylamino)ethylxanthine free base. The corresponding hydrochloride salt is then made on exposure to an excess of hydrogen chloride in solution.