Alkylation of ribose in RNA reacted with ethylnitrosourea at neutrality

Ribose oxygens in TMV-RNA are ethylated by the carcinogen ethylnitrosourea in neutral aqueous solution (pH 6.1-7.3). 2'-O-ethyluridine, and 2'-O-ethylcytidine have been identified as reaction products. The four 2'-O-ethyl nucleosides are found in approximately equal amounts and the total extent of ribose alkylation is about 15% of the total ethylation. This finding, in conjunction with earlier results showing that all ring and phosphate oxygens can be ethylated, signifies that every oxygen in RNA or polyribonucleotides can react with ethylnitrosourea. The possible biological significance of ribose alkylation, resulting from chemical rather than enzymatic reaction, is discussed. The preparation of the new derivative 2'(3')-Oethylguanosine is described.