A Convenient Synthesis of 8-Alkyl-2' (or 3')-azido (or amino)-2' (or 3')-deoxyadenosine as Diverse Synthetic Precursors of Cyclic Adenosine Diphosphate Ribose (cADPR)

As key nucleoside intermediates for the preparation of cyclic adenosine diphosphate ribose (cADPR, 1) analogues, 8-alkyl-2' (or 3')-azido(or amino)-adenosine derivatives (16-19) were successfully prepared by alkylating selectively protected adenosine derivatives (12, 13) via Pd(0) catalyzed cross-coupling reaction with tetraalkyltin reagents, followed by the sugar modification of these 8-alkyl-adenosine derivatives according to our precedent procedure. Compared to other precedent procedures, our 8-alkylation methodology using selectively TBDMS-protected 8-alkyl adenosine derivatives as starting materials will be utilized very conveniently to prepare highly functionalized adenosine analogues, which will be serve as key intermediates for the cADPR.