The alkylation of 2′-deoxyguanosine and of thymidine with diazoalkanes. Some observations on O-alkylation

Abstract

The reaction in ether–methanol between 2′-deoxyguanosine and diazomethane or its ethyl or n-butyl homologue gives 1-, O6- and 7-alkyl-2′-deoxyguanosine. N2,O6-Dimethyl-2′-deoxyguanosine was also detected. The hydrolysis of the methyl and the ethyl derivatives gives the corresponding alkylguanines: the O6-alkyl-2′-deoxyguanosines were sequentially hydrolysed, first to 2-amino-6-alkoxypurines, subsequently to guanine. The mass spectra of O6-alkyl-2′-deoxyguanosines (methyl and ethyl) and of the corresponding 2-amino-6-alkoxypurines were determined. The reaction of diazomethane with thymidine afforded O4-methylthymidine, in addition to the previously detected 3-methylthymidine.