含哌啶结构杂环醇的立体化学研究

用分子力学和量子化学计算方法(AM1)研究了含哌啶结构杂环醇(1_4)及其羧酸酯类化合物的立体化学问题.结果表明,在哌啶醇(1)及醇(3)分子中,4位羟基处于哌啶环的a键位时,环上的氮原子和羟基氧原子之间可能形成非经典的轨道超共轭作用,使其构型构象得到稳定.

Stereochemistry of the Heterocyclic Alcohols Containing Piperidine Unit

The stereochemistry of the heterocyclic alcohols(1_4) containing piperidine unit was studied on the basis of the results of molecular mechanics and quantum chemistry calculations. The results showed that there existed the nonclassical orbital superconjugated interactions between the nitrogen atom and oxygen atom which caused the conformations to be more stable when the hydroxylic group lay at axial than at equatorial with respect to the piperidine ring in compound 1 and compound 3 . If the axial hydrogen atoms at C2 and C6 positions in the piperidine ring were substituted, or the molecular existed in the polar solutions, this nonclassical orbital superconjugated interactions would be much weak even diminished. In this case, the conformations were more stable when the hydroxylic group at equatorial than at axial in these compounds.