Synthesis and antimicrobial activity of N-[(alpha-methyl)benzylidene]-(3-substituted-1,2,4-triazol-5-yl-thio) acetohydrazides

Agar-entrapped sulfonated DABCO: Agelly acidic catalyst for the acceleration of one-pot synthesis of 1,2,4-triazoloquinazolinone and some pyrimidine derivatives

In this project, a recently synthesized DABCO-based catalyst is entrapped in agar to reduce its moisture sensitivity leading to enhancement of its stability and catalytic activity. After preparation and identification this new reagent is used as an efficient and environmentally safe catalyst for the preparation of 1, 2, 4-triazoloquinazolinone and some pyrimidine derivatives. This method is accompanied with some superiorities such as, simple operation, mild and green conditions, use of low cost and non-hazardous natural material, short reaction times, easy preparation methods and simple work-up procedures. The prepared catalyst can be re-used for several times in all of the studied reactions without any appreciable loss in its activity.

DABCO-based ionic liquids: introduction of two metal-free catalysts for one-pot synthesis of 1,2,4-triazolo[4,3-a]pyrimidines and pyrido[2,3-d]pyrimidines

In this study, structurally functionalized 1,2,4-triazolo[4,3-a]pyrimidines and pyrido[2,3-d]pyrimidines were synthesized by two non-metal DABCO-based ionic liquids which were compared in catalytic activity in both reactions.

n-Bu4NI/TBHP-catalyzed C–N bond formation via cross-dehydrogenative coupling of 1H-1,2,4-triazoles (N–H) and methylarenes (Csp3–H)

An efficient n-Bu₄NI/TBHP-catalyzed protocol for C–N bond formation via cross-dehydrogenative coupling of 1H-1,2,4-triazoles (N–H) and methylarenes (C_sp3–H) has been developed under metal free conditions.

Cyclization of some carbothioamide derivatives containing antipyrine and triazole moieties and investigation of their antimicrobial activities

Acetohydrazide derivative containing both antipyrine and triazole nuclei (5) was obtained starting from ethyl hydrazinecarboxylate derivative (2) and 4-aminoantipyrine (1) by three steps. The treatment of compound 5 with CS(2) afforded the conversion of hydrazide function into 5-mercapto-1,3,4-oxadiazole ring leading to the formation of 7. Then, 7 gave the product containing triazolotriazine moiety (9) by the reaction with hydrazine hydrate. The synthesis of the compounds incorporating the 1,3,4-thiadiazole (10a-c), 1,2,4-triazole (11a-c) or 1,3-thiazole (12, 13) nucleus as third heterocycle was performed by the acidic or basic treatment of compounds 6a-c which were obtained from the reaction of 5 with several isothiocyanates, or by the condensation of 6a with two different phenacyl bromides, respectively. The antimicrobial activity study revealed that all the compounds showed good activities except 3-5.

Design and synthesis of novel N-benzylidenesulfonohydrazide inhibitors of MurC and MurD as potential antibacterial agents

A series of novel N-benzylidenesulfonohydrazide compounds were designed and synthesized as inhibitors of UDP-N-acetylmuramic acid:L-alanine ligase (MurC) and UDP-N-acetylmuramoyl-L-alanine:D-glutamate ligase (MurD) from E. coli, involved in the biosynthesis of bacterial cell-walls. Some compounds possessed inhibitory activity against both enzymes with IC₅₀ values as low as 30 μM. In addition, a new, one-pot synthesis of amidobenzaldehydes is reported.

Synthesis, determination of the lipophilicity, anticancer and antimicrobial properties of some fused 1,2,4-triazole derivatives

3-Unsubstituted and 3-substituted-7-aryl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazoles (1-14) were designed and obtained from biologically active 1-aryl-2-hydrazonoimidazolidines by cyclocondensation reaction with triethyl orthoformates (1-4), phenoxyacetic acid derivatives (5-13) and carbon disulfide (14), respectively. Their chemical structures were confirmed by IR, (1)H NMR, (13)C NMR, MS spectra and elemental analysis. In the high performance liquid chromatographic series of experiments, fourteen synthesized compounds (1-14) were chromatographed on octadecyl silica adsorbent and their lipophilicity parameter (logk(W)) was determined using various aqueous systems: mixture of water and organic modifiers (methanol - MeOH, acetonitrile - MeCN or dioxane - DX). Compounds 7 and 12 were evaluated for their cytotoxic activity against three cancer cell lines: human Caucasian colon adenocarcinoma cell line - LS180 (ECACC 87021202), human uterus carcinoma cell line - SiHa (ECACC 85060701) and human breast carcinoma cell line - T47D (ECACC 85102201). Compound 12 was found to be the most effective in vitro against human colon adenocarcinoma cell line (LS180). Moreover, the distinctly marked lower cytotoxicity of compounds 7 and 12 against the normal cell line - human skin fibroblasts (HSF) and almost several-fold higher against the examined cancer cell lines was ascertained. The cytotoxic effect of imidazotriazole 7 was noticed on DNA structure of breast cancer cell line (T47D) by using the comet assay. Compound 7 in concentration of 29.3 microM was found to possess efficiency for DNA strand breakage. In particular, this led to cutting of the DNA strands and formation of small fragments of DNA - two higher and one lighter in comparison with control DNA. Moreover, significant viability decreases in the human leukaemic RPMI 8226 cells treated with different concentrations of imidazotriazoles 8-12 were observed, suggesting their antiproliferative properties. Besides, three tested compounds (9, 13, 14) revealed significant antimicrobial activities with MIC values in the range of 30.9-44.0 microM. Compound 13 showed superior antibacterial activity to ampicillin and chloramphenicol in vitro, whereas 14 displayed superior antifungal activity to miconazole.

Synthesis of imidazoline and imidazo[2,1-c][1,2,4]triazole aryl derivatives containing the methylthio group as possible antibacterial agents

1-Arylimidazolidine-2-thiones (1a-g) were synthesized by the condensation reaction of N-arylethylenediamines with carbon disulfide in xylene medium. Their further alkylation with methyl iodide led to the formation of some biologically active 1-aryl-2-methylthio-imidazolines (2a-g). The 7-(4-methylphenyl)-3-methylthio-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (4b) was obtained by the alkylation of the respective 7-(4-methylphenyl)-2,5,6,7-tetrahydroimidazo[2,1-c][1,2,4]triazol-3(H)-thione (3b) with methyl iodide. Antimicrobial activities of 1-aryl-2-methylthio-imidazolines (2a-g) and the 7-(4-methylphenyl)-3- methylthio-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (4b) are presented. All tested compounds showed MIC in the range of 11.0-89.2 microM. Compounds 2a,e were found to be equipotent to chloramphenicol in vitro, whereas 2a,c,e-g and 4b showed superior activity (MIC) to ampicillin.

Synthesis and spectroscopic studies of mixed-ligand and polymeric dinuclear transition metal complexes with bis-acylhydrazone tetradentate ligands and 1,10-phenanthroline

Two types of dinuclear copper(II) and nickel(II) complexes with two tetradentate N2O2 donor ligands 1,4-bis(1-anthranoylhydrazonoethyl)benzene (L1), 1,4-bis(1-salicyloylhydrazonoethyl)benzene (L2) and N,N'-bidentate heterocyclic base [1,10-phenonthroline (phen)] have been synthesized and characterized by elemental analysis, infrared spectra, UV-vis electronic absorption spectra and magnetic susceptibility measurements. The reaction of metal(II) acetates with the solution containing ligand and 1,10-phenonthroline in methanol gives mixed-ligand dinuclear metal(II) complexes with general formula [M2L(phen)2]Cl2 (L=L1 or L2), whereas, the ligands react with metal(II) acetates to form polymeric dinuclear complexes with general formula [(M2L2)n] (L=L1 or L2). In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and amino groups of aroylhydrazone moiety do not participate in coordination. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes has been investigated.

Synthesis and antimicrobial activities of some new 1-(5-phenylamino-[1,3,4]thiadiazol-2-yl)methyl-5-oxo-[1,2,4]triazole and 1-(4-phenyl-5-thioxo-[1,2,4]triazol-3-yl)methyl-5-oxo- [1,2,4]triazole derivatives

Acetic acid ethyl esters containing 5-oxo-[1,2,4]triazole ring (2) were synthesized by the condensation of compounds 1a-f with ethyl bromoacetate in basic media. The reaction of compounds 2a-f with hydrazine hydrate led to the formation of acid hydrazides (3a-f). The treatment of compounds 3 with two divers aromatic aldehydes resulted in the formation of arylidene hydrazides as cis-trans conformers (4a,c,e,f, 5a,e,f). The thiosemicarbazide derivatives (6a,c,d,f) were afforded by the reaction of corresponding compounds 3 with phenylisothiocyanate. The treatment of compounds 6a,c,d,f with sulfuric acidic caused the conversion of side-chain of compounds 6a,c,d,f into 1,3,4-thiadiazol ring; thus, compounds 7a,c,d,f were obtained. On the other hand, the cyclization of compounds 6a,c,d,f in the presence of 2 N NaOH resulted in the formation of compounds 8a,c,d,f containing two [1,2,4]triazole rings which are linked to each other via a methylene bridge. Compounds 4a, f, 5a, 7a, d, f, 8a and d have shown antimicrobial activity against one or more microorganism, but no antifungal activity has been observed against yeast like fungi. Also inhibitory effect on mycelial growth by compounds 4e, 7d and 8f has been observed. Compounds 4c and 5f were found to possess antitumor active towards breast cancer.