Nucleosides and nucleotides. LXVII Synthesis of 8,2'-methanoguanosine and 9-(.ALPHA.-D-arabinofuranosyl)-8,2'-methanoguanine.
作者:HIROYUKI USUI、AKIRA MATSUDA、TOHRU UEDA
DOI:10.1248/cpb.34.1961
日期:——
Guanosine fixed in the high-anti conformation by means of an 8, 2'-methylene bridge was prepared. N2-Acetyl-O6-ethylguanosine (2) was converted to the 3', 5'-O-(tetraisopropyldisiloxane-1, 3-diyl) derivative (3). Oxidation of 3 to the 2'-keto derivative (4) and successive coupling with methylenetriphenylphosphorane gave the 2'-methylidene derivative (5) and its α-anomer. The 2'-methylidene function of 5 was hydroxylated, and the 2'-hydroxymethyl group was modified to give the phenylthiomethyl derivative (6). Photocyclization of 6 followed by deprotection of the sugar and base protecting groups furnished 8, 2'-methanoguanosine (12). The alpha anomer of 12 was likewise prepared. The circular dichroism spectra of 12, its α-anomer, and related compounds were measured.
通过 8,2'-亚甲基桥将鸟苷固定在高反构象上。将 N2-乙酰基-O6-乙基鸟苷 (2) 转化为 3',5'-O-(四异丙基二硅氧烷-1,3-二基)衍生物 (3)。将 3 氧化成 2'-酮衍生物 (4),然后与亚甲基三苯基膦连续偶联,得到 2'-亚甲基衍生物 (5) 及其 α-异构体。5 的 2'-亚甲基功能被羟基化,2'-羟甲基被修饰,得到苯硫甲基衍生物 (6)。对 6 进行光环化处理,然后对糖和碱保护基团进行脱保护处理,得到了 8,2'-甲基鸟苷(12)。12 的 α 异构体也同样被制备出来。测量了 12、其 α-异构体和相关化合物的圆二色光谱。