| 摘要 |
PCT No. PCT/US94/01728 Sec. 371 Date Nov. 26, 1996 Sec. 102(e) Date Nov. 26, 1996 PCT Filed Feb. 24, 1994 PCT Pub. No. WO94/19351 PCT Pub. Date Sep. 1, 1994Antihypertensive and bronchodilating compounds of the formula or a pharmaceutically acceptable salt thereof, and a process for preparing them are disclosed, wherein: R1, R2, R3, Ra, Rb and Rc as defined in the disclosure; pharmaceutical compositions containing said compounds; methods of treatment using said compounds; and a process for preparing polycyclic guanines comprising a) reducing a nitrosopyrimidine, and treating the reduced nitrosopyrimidine with an acylating reagent to give the amidopyrimidine; b) reacting the amidopyrimidine with a halogenating/cyclizing reagent to give a halopurine; c) reacting, in the presence of a base, the halopurine with an amine to give the substituted aminopurine; and d) closing the ring of the substituted aminopurine with a suitable dehydrating agent.
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