Simplified Liquid‐Phase Preparation of Four Decadeoxyribonucleotides and their Preliminary Spectroscopic Characterization

Four self‐complementary decadeoxyribonucleotides, dApTpApTpApTpApTpApT, dApTpApTpCpGpApTpApT, dApTpApTpGpCpApTpApT and dApApApApApTpTpTpTpT, were chemically synthesized by the phosphotriester procedure. Efforts were concentrated on keeping the procedure as simple as possible, concomitant with obtaining high‐purity products at each step of the process. The decamers were elaborated from the 3'‐end, starting with a 3'− O ‐benzoylated monomer according to the scheme: monomer + monomer → dimer + dimer → tetramer + dimmer → hexamer + tetramer → decamer. Purity of intermediates and of the fully blocked decamers were monitored by chromatography and by 300‐MHz 1 HN M R. spectroscopy. The deblocked decadeoxyribonucleotides were characterized by their UV., CD., and 1 HNMR. spectra.