Fused tricyclic analogues of guanosine for treating tumors

摘要

Fused tri-heterocyclic compounds of formula: R₁ is H or alkyl; R₂ is H, alkyl, alkenyl, aryl, heteroaryl, cyclyl, or heterocyclyl; R₃ and R₄, independently, is H, alkyl, alkenyl, aryl, heteroaryl, cyclyl, heterocyclyl, or (CR^aR^b)_mX(CR^cR^d)_nY; in which X is a bond, O, S, or NR^e; Y is alkoxy, aryloxy, heteroaryloxy, OC(O)R^e, C(O)R^e, N(R^eR^e'), NR^eC(O)R^e', S(O)₂R^e, or SR^e; each of m and n, independently, is 1, 2, 3, 4, or 5; each of R^a, R^b, R^c, R^d, R^e, and R^e', independently, is H, alkyl, aryl, heteroaryl, cyclyl, or heterocyclyl; and R₅ is H or halogen.