Structures of the Small-Molecule Bcl-2 Inhibitor (BH3I-2) and Its Related Simple Model in Protonated and Deprotonated Forms
作者:Daisuke Kanamori、Taka-aki Okamura、Hitoshi Yamamoto、Shigeomi Shimizu、Yoshihide Tsujimoto、Norikazu Ueyama
DOI:10.1246/bcsj.77.2057
日期:2004.11
3-Bromo-5-chloro-N-(2-chlorophenyl)-2-hydroxybenzamide (BCNCPB–OH) was synthesized as a model compound of the small-molecule Bcl-2 inhibitor (BH3I-2) and characterized by 1H NMR and IR measurements. The structures of BCNCPB–OH and its deprotonated form (BCNCPB–O–NEt4) were determined by X-ray analysis. BCNCPB–OH has an intramolecular OH···O=C hydrogen bond and BCNCPB–O–NEt4 has an intramolecular NH···O(oxyanion) hydrogen bond in the solid and solution states. The solution structures of protonated and deprotonated BH3I-2′ (BH3I-2 analogue) were determined by 1H NMR, NOESY, and IR measurements. They have similar conformations to those of the corresponding model compounds. A pKa value of BCNCPB–OH of 5.1 is considered a very low value for phenol derivatives, suggesting the possibility that BH3I-2 binds to protein in the deprotonated form having an intramolecular NH···O(oxyanion) hydrogen bond.
合成了 3-溴-5-氯-N-(2-氯苯基)-2-羟基苯甲酰胺 (BCNCPB-OH) 作为小分子 Bcl-2 抑制剂 (BH3I-2) 的模型化合物,并通过 1 H NMR 和红外测量。通过 X 射线分析确定了 BCNCPB-OH 及其去质子化形式 (BCNCPB-O-NEt4) 的结构。在固态和溶液状态下,BCNCPB–OH具有分子内OH·O=C氢键,BCNCPB–O–NEt4具有分子内NH·O(氧阴离子)氢键。通过 1 H NMR、NOESY 和 IR 测量确定了质子化和去质子化 BH3I-2'(BH3I-2 类似物)的溶液结构。它们具有与相应模型化合物相似的构象。 BCNCPB-OH 的 pKa 值为 5.1,对于苯酚衍生物来说被认为是非常低的值,这表明 BH3I-2 可能以具有分子内 NH·O(氧阴离子)氢键的去质子化形式与蛋白质结合。