Synthesis of 2'(R)-substituted neplanocin A's (nucleosides and nucleotides. XXXVII).
作者:KIYOFUMI FUKUKAWA、TOHRU UEDA、TAKAO HIRANO
DOI:10.1248/cpb.29.597
日期:——
Neplanocin A (I) was treated with 1, 3-dichloro-1, 1, 3, 3-tetraisopropyldisiloxane to give 3', 5'-O-(tetraisopropyldisiloxane-1, 3-diyl) neplanocin A (II), which was converted to the 2'-O-trifluoromethanesulfonyl derivative (III). Nucleophilic substitution of III with a number of nucleophiles (AcO-, AcS-, N3-, Cl-, Br-, I-) in hexamethylphosphoric triamide afforded the respective 2' (R)-substituted derivatives in high yield. The halogenated derivatives were reduced with tri-n-butyltin hydride to the 2'-deoxy compound. 2'-O-Thiocarbonylimidazoyl-3', 5'-O-(tetraisopropyldisiloxane-1, 3-diyl) neplanocin A was also reduced to the 2'-deoxy derivative. The deprotection of the bifunctional silyl group with tetra-n-butylammonium fluoride afforded 2' (R)-AcO, -AcS, -N3, -Cl, -Br, -I, and 2'-deoxy neplanocin A's, respectively. Physical data of these compounds including nuclear magnetic resonance, mass spectrum, and circular dichroism were given.
Neplanocin A(I)经 1,3-二氯-1,1,3,3-四异丙基二硅氧烷处理后,得到 3',5'-O-(四异丙基二硅氧烷-1,3-二基)neplanocin A(II),再将其转化为 2'-O-三氟甲烷磺酰基衍生物(III)。在六甲基磷酸三酰胺中,用多种亲核剂(AcO-、AcS-、N3-、Cl-、Br-、I-)对 III 进行亲核取代,可以高产率地得到相应的 2' (R)-取代衍生物。卤代衍生物用氢化三正丁基锡还原成 2'- 脱氧化合物。2'-O-Thiocarbonylimidazoyl-3', 5'-O-(tetraisopropyldisiloxane-1, 3-diyl) neplanocin A 也被还原成 2'-deoxy 衍生物。用四丁基氟化铵对双官能硅基进行脱保护,分别得到 2' (R)-AcO、-AcS、-N3、-Cl、-Br、-I 和 2'-deoxy 楝素 A。文中给出了这些化合物的物理数据,包括核磁共振、质谱和圆二色性。