AbstractTwo new series of complexes with pyridine‐containing Schiff bases, [VVO(SALIEP)L] and [VVO(Cl‐SALIEP)L] (SALIEP=N‐(salicylideneaminato)‐2‐(2‐aminoethylpyridine; Cl‐SALIEP=N‐(5‐chlorosalicylideneaminato)‐2‐(2‐aminoethyl)pyridine, L=catecholato(2−) ligand) have been synthesized. Characterization by 1H and 51V NMR and UV‐Vis spectroscopies confirmed that: 1) most complexes form two major geometric isomers in solution, and [VVO(SALIEP)(DTB)] (DTB=3,5‐di‐tert‐butylcatecholato(2−)) forms two isomers that equilibrate in solution; and 2) tert‐butyl substituents were necessary to stabilize the reduced VIV species (EPR spectroscopy and cyclic voltammetry). The pyridine moiety within the Schiff base ligands significantly changed their chemical properties with unsubstituted catecholate ligands compared with the parent HSHED (N‐(salicylideneaminato)‐N′‐(2‐hydroxyethyl)‐1,2‐ethanediamine) Schiff base complexes. Immediate reduction to VIV occurred for the unsubstituted‐catecholato VV complexes on dissolution in DMSO. By contrast, the pyridine moiety within the Schiff base significantly improved the hydrolytic stability of [VVO(SALIEP)(DTB)] compared with [VVO(HSHED)(DTB)]. [VVO(SALIEP)(DTB)] had moderate stability in cell culture media. There was significant cellular uptake of the intact complex by T98G (human glioblastoma) cells and very good anti‐proliferative activity (IC50 6.7±0.9 μM, 72 h), which was approximately five times higher than for the non‐cancerous human cell line, HFF‐1 (IC50 34±10 μM). This made [VVO(SALIEP)(DTB)] a potential drug candidate for the treatment of advanced gliomas by intracranial injection.
摘要 合成了两个新系列的含
吡啶席夫碱配合物,即[VVO(
SALIEP)L]和[VVO(Cl-
SALIEP)L](
SALIEP=N-(
水杨基亚
氨基)-2-(2-
氨基乙基)
吡啶;Cl-
SALIEP=N-(5-
氯水杨基亚
氨基)-2-(2-
氨基乙基)
吡啶,L=
邻苯二酚(2-)
配体)。通过 1H 和 51V NMR 以及 UV-Vis 光谱的表征证实了以下几点:1) 大多数配合物在溶液中形成两种主要的几何异构体,而[VVO(
SALIEP)(DTB)](DTB=
3,5-二叔丁基邻苯二酚(2-))在溶液中形成两种平衡的异构体;以及 2) 叔丁基取代基是稳定还原 VIV 物的必要条件(EPR 光谱和循环伏安法)。与母体 HSHED(N-(
水杨醛氨基)-N′-(2-羟乙基)-1,2-
乙二胺)席夫碱配合物相比,席夫碱
配体中的
吡啶基与未取代的
儿茶酚配体相比,其
化学性质发生了显著变化。未取代的
邻苯二酚 VV 复合物在
二甲基亚砜中溶解后立即还原成 VIV。相比之下,与[VVO(HSHED)(DTB)]相比,席夫碱中的
吡啶分子大大提高了[VVO(
SALIEP)(DTB)]的
水解稳定性。[VVO(
SALIEP)(DTB)]在
细胞培养基中具有中等稳定性。T98G(人胶质母细胞瘤)细胞对完整复合物有明显的细胞吸收,并具有很好的抗增殖活性(IC50 6.7±0.9 μM,72 小时),比非癌症人细胞株 HFF-1 的活性(IC50 34±10 μM)高出约五倍。这使得[VVO(
SALIEP)(DTB)]成为通过颅内注射治疗晚期胶质瘤的潜在候选药物。