SULFAMIDE REPLACEMENT OF THE PHOSPHODIESTER LINKAGE IN DINUCLEOTIDES - SYNTHESIS AND CONFORMATIONAL-ANALYSIS

Dinucleotide analogues d(TnsnT) and d(TnsnA), in which the phosphodies ter linkage of d(TpT) and d(TpA) is replaced by sulfamide [-NHSO2NH-], have been synthesised. Conformational analysis using (3)J vicinal cou pling constants shows that this modification results in a shift from a predominantly southern (C2'-endo) to northern (CS'-endo) ribose ring conformation. The effect of temperature and concentration changes on r ibose conformation, reveals that the modified dinucleosides have a gre ater propensity to base stack intramolecularly, and in the case d(Tnsn A), self-associate. (C) 1998 Elsevier Science Ltd. All rights reserved .