Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Outeiro de São João Batista, Niterói, RJ, 24020-141, Brazil.
Chemistry Institute, Federal University of Jataí (UFJ), BR 364 km 195, Jataí, GO, 75801-615, Brazil.
J Mol Model. 2022 Jul 30;28(8):239. doi: 10.1007/s00894-022-05234-4.
Plants from the Garcinia genus have been used worldwide due to their therapeutic properties. Among the various metabolites isolated from this genus, 7-epi-clusianone, a tetraprenylated benzophenone, stands out for its wide range of identified biological activities. This benzophenone can exist in five tautomeric forms, although the benzene-d and chloroform-d solution nuclear magnetic resonance (NMR) spectra revealed only two tautomeric forms (B and C) in equilibrium, with concentration ratio depending on the solvent in which the spectrum was obtained. Calculated energy values suggested that tautomeric forms B and E would be prevalent in benzene-d solution, in contrast to the experimental data. Considering this conflicting result, we employed the statistical DP4 + method based on C and H NMR chemical shift calculations, in the gas phase and in benzene-d solution, to confirm that the B and C tautomeric forms of 7-epi-clusianone are the most prevalent in the experimental conditions.
由于其治疗特性，藤黄属植物已在全球范围内使用。在从该属中分离出的各种代谢物中，7-epi-clusianone，一种四萜烯基二苯甲酮，因其广泛的已确定的生物活性而引人注目。这种二苯甲酮可以存在于五个互变异构形式中，但苯-d 和氯仿-d 溶液核磁共振（NMR）光谱仅显示两种平衡互变异构形式（B 和 C），其浓度比取决于获得光谱的溶剂。计算出的能量值表明，互变异构形式 B 和 E 将在苯-d 溶液中占优势，与实验数据相反。考虑到这一矛盾的结果，我们使用了基于 C 和 H NMR 化学位移计算的统计 DP4 + 方法，在气相中和苯-d 溶液中，以确认 7-epi-clusianone 的 B 和 C 互变异构形式是在实验条件下最普遍的。
