Abstract
An efficient one-flask synthesis of N2-isobutyryl-O6-[2-(4-nitrophenyl)ethyl]-5′-O-dimethoxytrityl-2′-deoxyguanosine by alkylation of N2-isobutyryl-3′-O-levulinyl-5′-O-dimethoxytrityl-2′-deoxyguanosine with 4-nitrophenylethanol in the presence of Ph3P, diethyl azodicarboxylate, and N-ethyl-N, N-diisopropylamine followed by 3′-O-deprotection with hydrazine is described.