Rapid and efficient stereocontrolled synthesis of C-3′-ethynyl ribo and xylonucleosides by organocerium additions to 3′-ketonucleosides
摘要:
In order to prepare new anti-retroviral nucleoside analogues, the effect of the group at C-5' on the addition of lithium and cerium trimethylsilylacetylide on 3'-ketonucleosidcs (R(1) = H, R(1) = TBDMS) derived from adenosine and uridine was studied. The best results in respect of yield (56 to 81%) and diastereoselectivity (95:5 to >98:2) were obtained with a cerium reagent (RCcCl(2)).
In order to prepare new anti-retroviral nucleoside analogues, the effect of the group at C-5' on the addition of lithium and cerium trimethylsilylacetylide on 3'-ketonucleosidcs (R(1) = H, R(1) = TBDMS) derived from adenosine and uridine was studied. The best results in respect of yield (56 to 81%) and diastereoselectivity (95:5 to >98:2) were obtained with a cerium reagent (RCcCl(2)).
3′-β-ethynyl and 2′-deoxy-3′-β-ethynyl adenosines: first 3′-β-branched-adenosines substrates of adenosine deaminase
The 3'-C-branched-adenosine and 2'-deoxyadenosineanalogues 1-7 were tested as substrate of adenosine deaminase. The 9-(3'-C-ethynyl-beta-D-ribo-pentofuranosyl)adenine 1 and its2'-deoxy analogue 7 were deaminated by the enzyme while the vinyl and ethyl derivatives 2 and 3 were not. The 9-(3'-C-branched-beta-D-xylo-pentofuranosyl)adenines 4-6 were deaminated by the deaminase.