反应详情

1,3,5-Pentanetriol linker derivatized CPG 10 and OligoPrep 11 were prepared starting from the commercially available diethyl 3-hydroxy glutarate 6 (Scheme 2). Reduction of 6 with LiAlH4 yielded 1,3,5-pentanetriol 7 in quantitative yield. The triol 7 was then selectively protected with DMTCl in the presence of DMAP to afford bis-DMT protected alcohol 8, which was then successfully converted into succinate 9, which is ready to load on to the solid support, by treating with succinic anhydride in the presence of DMAP. Attachment of 9 to CPG was accomplished in quantitative loading yield in the presence of DIC/DMAP in pyridine/acetonitrile mixture (10). Whereas, the above protocol gave very poor loading yield in the case of OligoPrep250, a PVA solid support, functionalization. However, quantitative loading yield was achieved in the presence of TBTU/DMAP in acetonitrile (11). The loading was maintained at about ˜40 μmol/g on CPG (10) and ˜125 μmol/g on OligoPrep250 (11) supports, respectively, which increases the nucleotide coupling efficiencies and final yields.