Substituent and solvent effects on the tautomeric equilibria of N-substituted .ALPHA.-(aminomethylene)purine-6-acetonitrile derivatives.
作者:Norimitsu HAMAMICHI、Tadashi MIYASAKA
DOI:10.1248/cpb.38.3253
日期:——
Substituent and solvent effects on the tautomeric equilibration (E/Z) of α-(N-alkyl and -arylaminomethylene)-9-(methoxymethyl)-9H-purine-6-acetonitriles (3a-q) have been studied by means of proton nuclear magnetic resonance spectroscopy in protic and aprotic solvents at 25°C. In chloroform-d these compounda (3a-q) exist mainly as the E-form. On the other hand, in methanol-d4 or dimethylsulfoxide-d6 the alkylamines (3a-c), phenylamine (3e), meta- or para-substituted phenylamines (3f-j) and 2, 6-disubstituted phenylamines (3p and q) exist mainly as the Z-form, while the trityl compound (3d), and ortho-substituted compounds (3k-o) showed a predominance of the E-form.
α-(N-烷基和-芳基氨基亚甲基)-9-(甲氧基甲基)-9H-嘌呤-6-乙腈(3a-q)的取代基和溶剂效应对其互变异构平衡(E/Z)的影响已通过在质子核磁共振光谱技术下,在质子溶剂和非质子溶剂中于25°C进行研究。在氘代氯仿中,这些化合物(3a-q)主要以E型存在。另一方面,在氘代甲醇或氘代二甲基亚砜中,烷基胺(3a-c)、苯胺(3e)、间位或对位取代的苯胺(3f-j)以及2, 6-二取代苯胺(3p和q)主要以Z型存在,而三苯基化合物(3d)和邻位取代的化合物(3k-o)则显示出E型的占优势。