Synthesis, characterization, and quantitative structure–activity relationship studies of bioactive dehydroacetic acid and amino ether Schiff base complexes

Abstract

Structural aspects of organosilicon(IV) and organotin(IV) complexes with dehydroacetic acid and amino ether Schiff base ligand have been described with the help of elemental analyses, conductance measurements, UV–Vis, infrared, multinuclear magnetic resonance, mass spectroscopy as well as thermogravimetric analysis, and X‐ray diffraction studies. Analysis of data suggested that the Schiff base provides two bidentate NO domains and was coordinated to silicon and tin moiety through the imine nitrogen and hydroxyl oxygen atom. Complexes were found to be nonelectrolytic and monomeric in nature. The thermal decomposition for tin compounds occurred in two steps and resulted into the formation of pure SnO2 as end product. The in vitro biological effects of the synthesized compounds were tested against two Gram‐positive and two Gram‐negative bacteria. The results of biological activity showed that all the complexes have enhanced activity as compared with the corresponding ligand, and compounds 5, 9, 11, 12, 13, 15, 16, and 17 were more potent than the standard drug ciprofloxacin. Compound 17 exhibited best antibacterial activity with lowest minimum inhibitory concentration value and maximum zone of inhibition. Further, quantitative structure–activity relationship studies pointed out that more stable compound were more active as antibacterial agents.

Synthesis, spectral analysis and in vitro cytotoxicity of diorganotin (IV) complexes derived from indole‐3‐butyric hydrazide

“…In the present work, hydrazide Schiff base ligands (1-4) were synthesized by the reaction of indole-3-butyric hydrazide with the salicylaldehyde and its derivatives in methanol solvent. Sixteen new diorganotin (IV) complexes (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) were prepared by reaction of hydrazide Schiff base ligands with R 2 SnCl 2 in 1:1 molar ratio by adding triethylamine as base. The spectroscopic data describes the synthesized diorganotin (IV) complexes to have pentacoordinated geometry with the tridentate ligands (ONO).…”

“…The organotin moiety is decisive for cytotoxicity, DNA cleavage, antimicrobial, anti-inflammatory, analgesic, antioxidant, antiHIV etc. [15][16][17][18][19][20] The ligand scaffolds also play a key role in the chemotherapy. Schiff base ligands having hydrazide groups are considered as "privileged ligands" and used widely due to their easy synthetic procedure, good solubility and their novel structural features.…”

Some divalent metal(II) complexes of salicylaldehyde‐derived Schiff bases: Synthesis, spectroscopic characterization, antimicrobial and in vitro anticancer studies

“…The coloured Schiff base products that precipitated out on refluxing were filtered and recrystallized from cold methanol and chloroform to afford the pure products. (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Transition metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) ions were prepared by reacting a hot methanolic solution (20 ml) of synthesized Schiff base (2 mmol) with a methanolic solution (10 ml) of metal acetate (1 mmol) with vigorous stirring for 2-3 h in a molar ratio of 2:1 at room temperature by adjusting the pH between 4 and 5 (Scheme 2). The different coloured solid complexes that precipitated out were filtered, washed with hot methanol and finally dried in hexane to afford the pure complexes.…”

“…Schiff base transition metal complexes have attracted much attention in the curative area due to their distinctive ligational behaviour, significant physicochemical properties and effective applications as new medicinal agents. A range of biological activities like DNA binding, antimicrobial, anticancer, antitubercular, antiangionesis, antiviral, antiparasitic, anti‐inflammatory, antipyretic, anti‐HIV and anticonvulsant activities and catalysis of various reactions, production of amino acids and drug interactions with biomolecules are also exhibited by Schiff base transition metal complexes. These biological applications are influenced greatly by the structure of the molecule, coordination number as well as the substituents bound on the Schiff bases …”

Synthesis, Biological Activity and QSAR Studies of Organotin(IV) and Organosilicon(IV) Complexes

“…The coordination chemistry of some ONO‐ and ONS‐donor Schiff bases has been described previously, and we have recently reported some organotin(IV) and organosilicon(IV) complexes with the potentially ON donor Schiff‐base ligands. As an extension of this research program and combined with the development of organotin(IV)/ organosilicon(IV) complexes of Schiff bases, we selected other interesting Schiff base ligands derived from 3‐hydroxy‐2‐methyl‐pyran‐4‐one with (2‐amino‐phenyl)‐methanol and aminobenzothiazole with O‐ and N‐donor sites.…”