Regioselective 1-alkylation of 2'-deoxyguanosine.

A method has been found for the regioselective alkylation of the nitrogen at the 1-position of 2'-deoxyguanosine. This consists in the reaction, in tetrahydrofuran solution, of a fully protected form of dG, namely the 3'5'-O-bis(tert-butyldimethylsilyl)-N2-dimethylaminomethylene derivative, with an alkyl halide in the presence of cesium carbonate. The yields of these previously unavailable derivatives of 2'-deoxyguanosine range from good to excellent. Confirmation of the structure of these substances comes from a comparison of their spectroscopic properties with those of the known 1-methyl homologue. In particular, the UV spectra of these new derivatives and the known 1-methyl homologue are essentially identical.