57(PB1-6) 2'-分枝糖ピリミジンヌクレオシドの合成(ポスター発表の部)

概要

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A series of 2'-branched-chain sugar pyrimidine nucleosides were synthesized from naturally occurring pyrimidine nucleosides for evaluation of antineoplastic and antiviral activities. Treatment of 2'-ulosyl pyrimidine nucleosides(4a,b) with Me_3Al or MeLi gave exclusively the arabino derivatives(13a-c), while with MeMgBr in Et_2O afforded the ribo derivatives(14a-c) in about 40% yields together with the arabino nucleosides. These tert-alcohols in 14a-c were converted into the methyl oxalate, which were then subjected to the radical deoxygenation with Bu_3SnH and AIBN to give the desired 2'-deoxy-2'(S)-methyl(20a,b) and 2'(S)-ethyl(20c) derivatives, respectively. The methyl oxalate of arabino nucleoside(22), however, gave a mixture of 2'(S)- and 2'(R)-methyl derivatives(23, 24) in a ratio of 3: 1. Each nucleosides were transformed to the corresponding cytosine nucleosides(5a,c), respectively. A new type of 2'-deoxycytidine analog, 2'-deoxy-2'-methylidene-cytidine(6a) was also synthesized by treatment of 4a with triphenyl-phosphonium methylide, followed by deblocking by F^-, then substitution with NH_3 at C-4 of the pyrimidine moiety. Antineoplastic and antiviral activities of compounds synthesized in this study will be discussed.
天然有機化合物討論会の論文
1987-07-25