Studies of Nucleosides and Nucleotides. XLII. Purine Cyclonucleosides. (9). Synthesis of Adenine Cyclonucleosides having 8, 2'-and 8, 3'-O-Anhydro Linkages

Abstract

2'-O-Triisopropylbenzenesulfonyl-8-bromoadenosine was converted to 8-oxy derivative either by treatment with sodium acetate in acetic acid or by sodium acetate in acetic anhydride-acetic acid mixture. 2'-Triisopropylbenzenesulfonyl-8-oxy-adenosine or its N6, 3', 5'-triacetyl derivative was cyclized to 8, 2'-anhydro-8-oxy-9-β-D-arabinofuranosyladenine with sodium acetate in dimethyl formamide (DMF). Cyclization of 2'- and 3'-triisopropylbenzenesulfonyl-8-oxy derivative was kinetically followed and it was found that the former cyclized easier than the latter compound and decomposition of both cyclonucleosides differed greatly in its rate. Using short cyclization time 8, 3'-anhydro-8-oxy-9-β-D-xylofuranosyladenine was first synthesized from 3'-O-triisopropylbenzenesulfonyl-8-oxyadenosine. Optical rotatory dispersion (ORD) and circular dichroism (CD) curves of these cyclonucleosides were described.