Abstract
N1-Oxides of 8, 2'-, 8, 3'- and 8, 5'-S-cycloadenosine were synthesized by the oxidation using monoperphthalic acid. The structure of these N-oxides was confirmed by unambiguous synthesis from 2'- or 3'-O-triisopropylbenzenesulfonyl-8-bromoadenosine, which were oxidized at N1-atom and cyclized with NaSH to give 2'- or 3'-S-cyclonucleoside N-oxide. For 5'-isomer, 2', 3'-ethoxymethylidene-5'-tosyl-8-bromoadenosine was converted to 8-mercapto N1-oxide by the successive treatment with monoperphthalic acid and NaSH. Cyclization with sodium acetate in dimethylformamide and removal of ethoxymethylidene group with acetic acid gave 8, 5'-S-cycloadenosine N1-oxide. Ultraviolet and nuclear magnetic resonance spectral properties of these N-oxides were investigated.
