The conformational analysis of saturated heterocycles. Part XXIII. Hexahydropyrimidines
作者:Richard A. Y. Jones、A. R. Katritzky、M. Snarey
DOI:10.1039/j29700000131
日期:——
The preparations of some N-substituted hexahydropyrimidines are described. Their electric dipole moments have been measured in cyclohexane solution and interpreted in terms of their conformations. The conformational free-energy differences between axial and equatorial N-methyl and N-ethyl groups are a little smaller than in the corresponding N-alkylpiperidines and accord with a repulsion between two
描述了一些N-取代的六氢嘧啶的制备。它们的电偶极矩已在环己烷溶液中测量,并根据其构象进行了解释。轴向和赤道的N-甲基和N-乙基之间的构象自由能差略小于相应的N-烷基哌啶,并且与两个轴向孤电子对之间的排斥力约为0·3 kcal./mol。对于N-异丙基,其构象自由能差高得惊人。建议一个可能的解释。