The synthesis of three potentially tetradentate, N2S2 Schiff-base-ligands, containing a disulfide bond, (LSSLThio)-S-Thio(L1), (LSSLBr)-S-Br(L2) and (LSSLDiMeO)-S-DiMeO (L3) are reported. These ligands undergo reductive disulfide bond scission upon reaction with PPh3 in the presence of Zn2+ ion. [(LS)-S-DiOMe](-), [(LS)-S-Thio](-) and [(LS)-S-Br](-) are the resulting bidentate thiolate-imine anions respectively, which upon reaction with Zn2+ produce three new zinc (II) complexes: [Zn((LSN)-S-Thio)(2)] (1), [Zn((LSN)-S-Br)(2)] (2) and [Zn((LSN)-S-DiOMe)(2)] (3). The structures of (L1) and 1-3 complexes were determined by X-ray diffraction. The interaction of 1-3 with CT-DNA have been investigated by absorption, emission, and CD spectroscopic methods and thermal denaturation measurements. The resulting data reveal that 1-3 show effective binding to CT-DNA (K-b = 2.2 x 10(4) to 1 x 10(5) L mol(-1)). The binding mode of DNA with 1-3 has also been investigated by molecular docking. The protein binding ability of 1-3 has been tested by monitoring the tryptophan emission intensity using BSA as a model protein. The quenching mechanism of BSA by the zinc complexes is static (k(q) = 1.66 to 3.4 x 10(13) L-1 mol s(-1)). It is remarkable that 1-3 exhibit effective cytotoxicity against two human tumour cell lines (HeLa and MCF-7). The potent cytotoxic effects of 2 and 3, with IC50 values of 19.93 and 20.11 respectively, are higher relative to clinically used cisplatin (IC50 = 23.50) against the MCF-7 cell line, indicating that 2 and 3 may have the potential to act as effective metal-based anticancer drugs.
Cubic Ag<sub>2</sub>O nanoparticle incorporated mesoporous silica with large bottle-neck like mesopores for the aerobic oxidative synthesis of disulfide
dispersed on mesoporous silica with large bottle-neck like mesopores were synthesized and characterized by BET surface area analysis, HR TEM, EDX, FTIR and powder XRD studies. The Ag2O nanoparticles were homogeneously distributed having an average size of 20–40 nm. The activity of the catalyst was probed through an efficient aerobic chemoselective oxidation of thiols to disulfides in water under atmospheric
Efficient Synthesis of 2-Arylbenzothiazole Derivatives with the Aid of a Low-Valent Titanium Reagent
作者:Da-Qing Shi、Shao-Feng Rong、Guo-Lan Dou
DOI:10.1080/00397910903227230
日期:2010.7.12
A novel and facile synthesis of 2-arylbenzothiazole derivatives was accomplished in good yields via the novel reductive cyclization of bis-(2-benzalaminophenyl)disulfide promoted by the TiCl4/Sm system. The advantages of this new method are the easily accessible starting materials, short reaction time, and moderate to good yields.