Nucleotides. Part L. Aglycone protection by the (2-dansylethoxy)carbonyl (= {2-{5-(dimethylamino)naphthalen-1-yl]sulfonyl}ethoxy}carbonyl; dnseoc) group - A new variation in oligodeoxyribonucleoside synthesis

Article abstract of DOI:10.1002/hlca.19970800118

The (2-dansylethoxy)carbonyl (= {2-{[5-(dimethylamino)naphthalen-1-yl]sulfonyl}ethoxy}carbonyl; dnseoc) group was employed for protection of the amino functions of the aglycone residues. The lactam function of 2'-deoxyguanosine was on the one hand unprotected and on the other hand alkylated at O⁶ of the aglycone with the 2-(4-nitrophenyl)ethyl (npe) and 2-(phenylsulfonyl)ethyl (pse) group, respectively. The syntheses of monomeric building blocks, both phosphoramidites and nucleoside-functionalized supports, are described for the three common 2'-deoxynucleosides (2'-deoxycytidine, 2'-deoxyadenosine, 2'-deoxyguanosine). As kinetic studies with the tritylated nucleosides showed, the dnseoc group is more labile towards DBU cleavage than the corresponding 2-(4-nitrophenyl)ethyl-(npe) and [2-(4-nitrophenyl)ethoxy]carbonyl(npeoc)-protected analogues. These results were confirmed by the very fast deprotection rate of the dnseoc groups at some oligonucleotides.