NMR spectroscopic and theoretical study on the isomerism of dimethyl benzodiazepine(diylidene)diacetates
作者:Dirk Michalik、Haijun Jiao、Peter Langer
DOI:10.1002/mrc.5272
日期:2022.8
4-(3H,5H)diylidene)diacetate (1a) and dimethyl 2,2′-(7,8-dichloro-3-methyl-1H-benzo[b][1,4]diazepine-2,4-(3H,5H)diylidene)diacetate (1b) was investigated by 1H, 13C and 15N nuclear magnetic resonance (NMR) spectroscopy. In CDCl3 solution, inversion of the diazepine ring was observed, whereas in (D6)DMSO and (D7)DMF solution, besides the ring inversion, a partial cleavage of one chelate ring appeared connected
2,2'-(7,8-dichloro-1 H -benzo[ b ][1,4]diazepine-2,4-(3 H ,5 H )diylidene) 二乙酸二甲酯 ( 1a ) 和二甲基 2的异构体,2'-(7,8-dichloro-3-methyl-1 H -benzo[ b ][1,4]diazepine-2,4-(3 H ,5 H )diylidene) diacetate ( 1b ) 由1 H、13 C 和15 N 核磁共振 (NMR) 光谱。在 CDCl 3溶液中,观察到二氮杂环倒置,而在 ( D 6 )DMSO 和 ( D 7)DMF 溶液,除了环反转外,一个螯合环的部分裂解出现与环外 C=C 键之一的( E / Z ) 异构化有关。基于 B3PW91-SCRF/ZVP DFT 计算计算吉布斯自由能 (ΔG) 和自由活化能 (ΔG ≠ )。发现 NMR 数据和密度泛函理论 (DFT)