Aminations of guanosine and deoxyguanosine with hydroxylamine-O-sulfonic acid and 2,4-dinitrophenoxyamine. Dependence on the reaction medium.

Amination of guanosine (Guo) with 2,4-dinitrophenoxyamine in aqueous DMF gave 7-amino-Guo, which was readily converted to 8,5'-O-cyclo-Guo, and 8-hydroxy-Guo. Deoxyguanosine (dG) gave only deglycosylated 7-amino-G under the same reaction condition. Aminations of Guo and dG with hydroxylamine-O-sulfonic acid above pH 9 gave the corresponding 1-amino derivatives, whereas those in acidic media at pH 2-4 gave 8-amino-Guo and 7-amino-G as the main products, respectively. Amination of Guo in neutral media gave 1-amino-Guo and decomposed products of 7-amino-Guo. The mechanisms of these amination reactions are described.