An O 6 -methylguanosine derivative (1) was treated with isoamyl nitrite in the presence of a cyclic ether such as trimethylene oxide, tetrahydrofuran, or tetrahydropyran to give the corresponding 2-nitrooxyalkoxy-6-methoxypurine riboside derivatives (2a-c).
O(6)-Methylguanosine and 2-amino-6-chloropurine riboside derivative were treated with isoamylnitrite in the presence of an appropriate alcohol to give the corresponding 2-alkoxy-6-methoxy (or chloro) purine riboside derivatives.