Jones G P, Andrews P R
J Med Chem. 1980 Apr;23(4):444-8. doi: 10.1021/jm00178a017.
Conformational energy calculations are reported for a series of convulsant and anticonvulsant barbiturates derived from 5-ethyl-5-(1'-methylbutyl)barbituric acid (pentobarbital) by minor structural changes to the butyl side chain. A number of low-energy conformations are identified for each barbiturate. In each case substantial barriers to rotation exist between the alternative conformations, and the magnitudes of these barriers suggest that the barbiturates may be conformationally restricted even at physiological temperatures. Fully extended conformations, with both side chains perpendicular to the plane of the barbiturate ring, are favored. In the 1'-methyl derivatives, conformations with the 1'-methyl group located directly above the barbiturate ring are equally low in energy.
报道了一系列由5-乙基-5-(1'-甲基丁基)巴比妥酸（戊巴比妥）通过对丁基侧链进行微小结构变化而得到的惊厥性和抗惊厥性巴比妥酸盐的构象能计算结果。为每种巴比妥酸盐确定了许多低能量构象。在每种情况下，不同构象之间存在显著的旋转障碍，这些障碍的大小表明巴比妥酸盐即使在生理温度下也可能在构象上受到限制。两个侧链均垂直于巴比妥酸环平面的完全伸展构象是有利的。在1'-甲基衍生物中，1'-甲基基团直接位于巴比妥酸环上方的构象能量同样较低。
