A novel method for the methylation of heterocyclic amino groups. Conversion of guanosine into its 2- N-methyl- and 2- N,2- N-dimethyl derivatives

Abstract

The heterocyclic amino-compounds 11a, 13a, 13b, and 17 reacted with formaldehyde and p-thiocresol ( 14) in alcoholic solution to give the corresponding N-methylphenylthiomethyl derivatives ( 16, 15a, 15b, and 18a, respectively) in satisfactory to good yields. The reactions were catalyzed by acetic acid. 2- N-Methylguanosine ( 6a) was obtained in good yield by treatment of 15b with sodium borohydride followed by acidic hydrolysis, or alternatively by Raney nickel desulfurization of 15a followed by ammonolysis of the product. Sodium borohydride reduction of 18a gave 21 in good yield. 2- N,2- N-Dimethylguanosine ( 6b) was obtained from 19a in three steps.