Sugara-oligoamides: Synthesis of DNA minor groove binders

摘要

Sugar-oligoamides have been designed and synthesized as structurally simple carbohydrate-based ligands to study carbohydratea-minor groove DNA interactions. Here we report an efficient solution-phase synthetic strategy to obtain two broad families of sugara-oligoamides. The first type, structure vector A (-Py[Me]-γ-Py-Ind), has a methyl group present as a substituent on the nitrogen of pyrrole B, connected to the C terminal of the oligoamide fragment. The second type, structure vector B (-Py[(CH_2) _(11)OH]-γ-Py-Ind), has an alkyl chain present on the nitrogen of pyrrole B connected to the C terminal of the oligoamide fragment and has been designed to access to di-and multivalent sugara-oligoamides. By using sequential DIPC/HOBt coupling reactions, the oligoamide fragment-Py[R]-γ-Py-Ind has been constructed. The last coupling reaction between the anomeric amino sugar and the oligoamide fragment was carried out by activating the acid derivative as a BtO-ester, which has been performed by using TFFH. The isolated esters (BtO-Py[R]-γ-Py-Ind) were coupled with selected amino sugars using DIEA in DMF. The synthesis of two different selective model vectors (vector A (1) and vector B (2)) and two types of water-soluble sugara-oligoamide ligands, with vector A structure (compounds 3a-7) and with vector B structure (compound 8), was carried out.