The atropisomeric and conformational properties of 1,4-benzodiazepin-2-ones were investigated by freezing the conformation with a methyl group at the C9 of 1,4-benzodiazepine. It was revealed that 1,4-benzodiazepin-2-ones exist only as a pair of enantiomers [(a¹ R, a² S) and (a¹ S, a² R)], which was confirmed by X-ray analysis. The absolute configuration of each atropisomer was deduced by comparing the [α]_D and CD data with those of (–)-N-methoxycarbonylmethylated 9-methyl-5-phenyl-1,4-benzodiaepin-2-one derivative. It was elucidated that the corresponding N-methylated derivative showed similar CD spectra, although the rotational direction of [α]_D was opposite to that of others.

通过在 1,4-苯并二氮杂卓的 C9 处冻结具有甲基的构象，研究了 1,4-苯二氮卓-2-酮的阻转异构和构象特性。结果表明，1,4-苯二氮卓-2-ones仅以一对对映体[(a ¹ R , a ² S )和(a ¹ S , a ² R )]的形式存在，X射线分析证实了这一点. 每个阻转异构体的绝对构型是通过将 [α] _D和 CD 数据与 (-)- N-甲氧基羰基甲基化 9-甲基-5-苯基-1,4-苯并二烯-2-one 衍生物的数据进行比较来推导出来的。说明相应的N-甲基化衍生物表现出相似的CD光谱，尽管[α] _D的旋转方向与其他的相反。