Elucidation of the Microwave-Assisted Synthesis and Characterization of Heteronuclear Complexes of Bisbenzimidazole Derivatives and Their Biological Activities by In Vitro and In Silico Assays.

A novel and efficient protocol for the microwave-assisted synthesis of diversely substituted 2,2'-bisbenzimidazol-5,6'-dicarboxylic acid (BIMCA) from the reaction of 3,4-diaminobenzoic acid with oxalic acid has been developed, which proceeds through sequential nucleophilic addition and electrophilic substitution in accordance with the Philips method. The synthetic utility of this strategy was demonstrated by the concise, one-pot synthesis of (BIMCA) and metal complexes. (BIMCA) with a [{Fe(salen)}2O] Schiff base ligand complex and new benzimidazole coordination compounds with double oxygen [(BIMCA){Fe(salen)}2] ligand complexes were obtained. The resulting [(BIMCA){Fe(salen)}2] ligand complex was then synthesized from Co(CH3COO)2.4H2O, Ni(CH3COO)2.4H2O and Cu(CH3COO)2.H2O heteronuclear complexes. The condensations proceed with good yield to give products that, in certain instances, are not readily attainable by conventional condensation techniques. The structures of the compounds were identified by Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), elemental analysis and magnetic susceptibility. The mutagenic potential of the synthesized chemicals was evaluated by the Ames test towards mutant Salmonella typhimurium strains TA98 and TA100. It was recorded that these chemicals had no mutagenic action. Also, antimicrobial activities were screened by broth microdilution test. It was seen that the minimum inhibitory concentration (MIC) against Klebsiella pneumoniae, Staphylococcus aureus and Staphylococcus epidermidis was 0.195 mg/mL, followed by a MIC value of 0.390 mg/mL against Escherichia coli and Salmonella typhimurium. [(BIMCA){Fe(salen)}2Co(II)] demonstrated significant antimicrobial activity against Proteus mirabilis and Staphylococcus aureus, with an MIC of 0.195 mg/mL, followed by an MIC of 0.390 mg/mL against Pseudomonas aeruginosa, K. pneumonia and Salmonella typhimurium. The antioxidant properties were examined using various chemical assays, and [(BIMCA){Fe(salen)}2O] and (BIMCA) exhibited greater 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, when compared with other compounds. Enzyme inhibitory effects were tested against acetylcholinesterase (AChE), amylase, butyrylcholinesterase (BChE) and tyrosinase. [(BIMCA){Fe(salen)}2Cu(II)] displayed the best AChE (IC50 0.51 mg/mL), BChE (IC50 0.51 mg/mL) and tyrosinase (IC50 1.52 mg/mL) inhibitory effects. Furthermore, molecular docking calculations were performed to gain insights into the interaction between [(BIMCA){Fe(salen)}2] and AChE, and between [(BIMCA){Fe(salen)}2Cu(II)] and amylase. Both compounds showed the potential inhibition of the protein targets.

Synthesis and Characterization of Cross Linked Acetoguanamine Polymer Complexes: Investigation of their Thermal and Magnetic Properties.

In this study, 2,4-diamino-6-methyl-1,3,5-triazine (acetoguanamine) was used as the starting material. 2,4-diamino-6-methyl-1,3,5-triazine was boiled under reflux with glutaraldehyde and terephthaldehyde in acetonitrile. And, s-triazine-containing polymer ligands (IV and V) were obtained by these condensation reactions. These target s-triazin containing polymer ligands we obtained were analyzed by 1H-NMR, FT-IR and elemental analysis. Then, polymeric metal (Co2+, Ni2+ and Cu2+) complexes of the polymeric ligands (VI-XI) were obtained from the interaction with CoCl2 ∙ 6H2O, NiCl2 ∙ 6H2O and CuCl2 ∙ 2H2O at 60 ℃ in ethyl alcohol. The structures of these complexes were also illuminated and elucidated using FT-IR, elemental analysis and magnetic susceptibility analysis. The polymerization degrees of the polymeric ligands were determined by the molecular weight determination study with the viscometer.

Synthesis of novel dopamine derived multidirectional ligands from cyanuric chloride: structural and antimicrobial studies.

Two monopodal (2,4-dichloro-6-(3-hydroxytyramine)-1,3,5-triazine) and tripodal (2,4,6-(3-hydroxytyramine)-1,3,5-triazine) s-triazine derivatives were prepared through the reaction of cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) and 3-hydroxytyramine hydrochloride (dopamine hydrochloride). The structures of the compounds were identified by FT-IR, 1H NMR, 13C NMR, thermal analysis and elemental analysis. Their antimicrobial activities were carried out using the broth microdilution method in dimethyl sulfoxide (DMSO): Phosphate Buffered Saline (PBS) against eight bacteria and one yeast. The results of the test were compared with ampicillin. It was determined that CCDOP1, CCDOP3 and DOP have significant antibacterial and antifungal activity. These three chemicals revealed strong antibacterial activity against the E. coli and S. aureus strains used in the study. S. aureus was the most sensitive strain against dopamine hydrochloride and E. coli was the most sensitive bacteria against CCDOP1.

Synthesis and characterization of dendrimeric melamine cored [salen/salophFe(III)] and [salen/salophCr(III)] capped complexes and their magnetic behaviors.

2,4,6-Tris(4-hydroxybenzimino)-1,3,5-triazine [1] 2 has been synthesized from the reaction of 1 equiv. melamine (2,4,6-triamino-1,3,5-triazine) and 3 equiv. 4-hydroxybenzaldehyde. Then, 2,4,6-tris(4-(4,6-dichloro-1,3,5-triazine-2-yloxy)benzimino)-1,3,5-triazine 3 has been synthesized from the reaction of 1 equiv. 2 and 3 equiv. cyanuric chloride. And then, two new triazine centered dendrimeric ligands 2,4,6-tris(4-(4,6-bis(4-carboxyphenyloxy)-1,3,5-triazine-2-yloxy)benzimino)-1,3,5-triazine 4 and 2,4,6-tris(4-(4,6-bis(3,5-dicarboxyphenyloxy)-1,3,5-triazine-2-yloxy)benzimino)-1,3,5-triazine 5 have been synthesized from the reaction of 1 equiv. 3 and 6 equiv 4-hydroxybenzoic acid or 5-hydroxyisophtalic acid. Finally, eight new multinuclear Fe(III) and Cr(III) complexes involving tetradenta Schiff bases N,N'-bis(salicylidene)ethylenediamine-(salenH(2)) or bis(salicylidene)-o-phenylene diamine-(salophH(2)) with 4 or 5 have been synthesized and characterized by means of elemental analysis, (1)H NMR, FT-IR spectroscopy, thermal analyses and magnetic susceptibility measurements. The complexes can also be characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by carboxylic acids.

Synthesis of novel tripodal-benzimidazole from 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine: structural, electrochemical and antimicrobial studies.

Four new tripodal-benzimidazole derivatives were synthesized by Schiff base reaction between 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine (TRIPOD) and different diamine derivatives. The structures of the obtained compounds were identified by FT-IR, (1)H NMR, (13)C NMR and UV-vis spectral data, thermal analysis and elemental analysis. Electrochemical behaviors of the compounds were studied by cyclic voltammetry in DMF including 0.1 M [NBu(4)] [PF(6)]. The voltammograms showed peaks having similar characteristics except tripodal-benzimidazole including -NO(2) derivative. In addition, their antimicrobial activities were evaluated by using the standard disk diffusion method in dimethylformamide media. The activities were determined against 4 bacteria cultures by comparing to those of gentamycin.