Synthesis of benzimidazole derivatives as potential H1-antihistaminic agents

Several types of benzimidazole derivatives were prepared and were screened for H ₁-antihistaminic activity. Most of the compounds showed potent antihistaminic activity in vitro. Among them 2-[(1-piperazinyl)methyl]-benzimidazoles 14 and 2-[(1-homopiperazinyi)methyl]benzimidazoles 15 exhibited potent activity also in vivo.     

Synthesis and biological evaluation of benzimidazole pendant cyanopyrimidine derivatives as anticancer agents

Thirteen new benzimidazole pendant cyanopyrimidine derivatives were synthesized. The compounds were synthesized through multistep reaction protocol. The structures of synthesized derivatives were studied by EI-MS, ¹H NMR, FT-IR and elemental analysis. All the compounds were studied for their anticancer activity at National Cancer Institute. Except compound 7j , all the compounds unveiled cytotoxicity against cancer cells. The most active compound 7a had shown highest value of growth inhibition of 88.44% and 84.19% against HOP-92 and T-47D cancer cell lines.     

Quantitative structure-activity relationship of catechol derivatives inhibiting 5-lipoxygenase.

Various catechol derivatives (beta-substituted 3,4-dihydroxystyrenes, 1-substituted 3,4-dihydroxybenzenes, and 6-substituted 2,3-dihydroxynaphthalenes) were synthesized and their inhibition of 5-lipoxygenase was assayed. Their structure-activity relationships were examined quantitatively with substituent and structural parameters and regression analysis. The variations in the inhibitory activity were explained in bilinear hydrophobic parameter (log P) terms, and steric (molecular thickness) and electronic (proton nuclear magnetic resonance (1H-NMR) chemical shift of the proton adjacent to the catechol group) parameter terms. The hydrophobicity of the inhibitor molecule was important, and the optimum value of logP was about 4.3-4.6, beyond which inhibition did not increase further. A lower electron density of the aromatic ring containing the catechol group and the greater thickness of the lipophilic side chains were unfavorable to the activity. The results added a physicochemical basis for the selection of candidate compounds for developmental studies.     

Synthesis of 2-alkoxy 1,4-naphthoquinone derivatives as antiplatelet,antiinflammatory, and antiallergic agents

In our continuing search for novel antiplatelet, antiallergic, and antiinflammatory agents, 2-alkoxy derivatives of 1,4-naphthoquinone were prepared. Some of these compounds showed significant antiplatelet, antiallergic, and antiinflammatory activities. Among them, 2-propoxy-1,4-naphthoquinone and 2-butoxy-1,4-naphthoquinone exhibited potent inhibitory effect on neutrophil superoxide anion formation. These two compounds are worthy of further exploration.     

Studies on antiallergic agents. I. Synthesis and antiallergic activity of novel pyrazine derivatives.

Various pyrazine derivatives were synthesized and their antiallergic activity was examined. The inhibitory activity on allergic histamine release of the compounds bearing a 5-tetrazolyl group was more potent than that of the corresponding carboxyl derivatives. The introduction of -CONH- or -NHCO- between the pyrazine ring and the 5-tetrazolyl group as a spacer greatly enhanced the activity. N-(1H-Tetrazol-5-yl)-2-pyrazinecarboxamide (I-3) was estimated to exhibit nearly the same potency as disodium cromoglycate (DSCG). The structure-activity relationship among various derivatives modified by introducing some substituents onto the 3-, 5- or 6-position of the pyrazine ring of I-3 was investigated. The activity remained unchanged or was reduced when such substituents as methyl, chloro, methoxy, methylamino and dimethylamino were introduced at the 3- or 5-position. In contrast, 6-substitution with various alkylamino groups more or less increased the activity. Among them, the 6-dimethylamino (I-17c) and 6-(1-pyrrolidinyl) (I-34) derivative were proved to be most potent. The IC50 values (concentration which produces 50% inhibition of the allergic histamine release) of I-17c and I-34 were determined to be 4.7 x 10(-10) and 4.6 x 10(-10) M, respectively. These two compounds produced a potent inhibitory activity on passive cutaneous anaphylaxis (PCA) in rat, not only by the intravenous route (ED50 = 0.0096 mg/kg for both compounds) but also by the oral route (ED50 = 0.19 and 0.18 mg/kg, respectively). On the other hand, when the pyrazine ring of some representative compounds was replaced with a pyridine ring, the inhibitory activity on histamine release was significantly reduced.     

Synthesis of benzimidazole derivatives

In an aqueous medium, the reaction of N-sodio-2-methylbenzimidazole with monohalogen-substituted nitrogenous aromatic heterocycles containing the halogen in the position to the nitrogen atom may be considered as amethod for obtaining N-betaryl-2-methylbenzimidazoles. 1-(Benzoxazol-2-yl)- and 1-(benzothiazol-2-yl)-2-methylbenzimidazoles have been synthesized; imidacyanine dyes have been obtained with benzothiazol-2-yl groups on the nitrogen atoms of the benzimidazole nuclei from the methiodide of the latter.For Communication V, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1542–1544, November, 1973.     

Synthesis of benzimidazole derivatives

A general method for the synthesis of symmetrical imidatricarbocyanines is proposed. A number of dyes of this group were synthesized, and the positions of their light absorption maxima in alcohol solution were determined.See [1] for communication VIII.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 11, pp. 1562–1563, November, 1976.     

Synthesis of benzimidazole derivatives

Imidadicarbocyanines containing a chloro, bromo, or methyl group in the polymethine chain were synthesized in order to investigate their optical properties.See [1] for communication VI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 254–257, February, 1975.     

Synthesis of benzimidazole derivatives

Phenylhalides of 1-phenyl-2-methylbenzimidazole were synthesized and converted to a new type of imidacyanin dye with phenyl groups on both nitrogen atoms of the benzimidazole residue. The heretofore unknown imidadicarbocyanins were obtained from quaternary salts of 1-phenyl-2-methylbenzimidazole (or its derivatives) which contain electronegative substituents in the 5 position.See [1] for Communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1559–1561, November, 1970.     

Synthesis of benzimidazole derivatives

New bases and quaternary salts — 2-methylbenzimidazole derivatives — containing 2-pyridyl residues as a substituent in various positions of the benzimidazole ring were synthesized. Benzimidazolium salts of a new type with hetaryl groups attached to both nitrogen atoms were obtained. Imidacyanines were synthesized from the quaternary salts of pyridyl-substituted 2-methylbenzimidazoles, and the chief light-absorption maxima of these dyes were determined.See [1] for communication IVTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 687–690, May, 1972.     

Synthesis of fluorine-containing benzimidazole derivatives

Various fluorine-containing benzimidazoles were obtained by the reaction of o-phenylene-diamine, 3,4-diaminotoluene, and 1,2-diamino-4-chlorobenzene with hexafluoropropene or perfluoro(methyl vinyl ether) in DMF. A new efficient method of synthesis of 2-(1,2,2,2-tet-rafluoroethyl)benzimidazole by the reaction of o-phenylenediamine with hexafluoropropene in the presence of diethylamine or dimethylamine in ethyl acetate is developed.     

Synthesis,biological evaluation and SAR studies of benzimidazole derivatives as H1-antihistamine agents

A series of benzimidazole derivatives have been designed,synthesized and evaluated for H₁ antihistamine activity.Six compounds have showed potent antihistamine H₁ activity.The primary SAR analysis indicated that benzyl or benzylidinyl substituted on the exo-nitrogen atom and C2 of the benzimidazole were significant.Further experiments indicated that compound 17d displayed excellent activity to reduce mast cell degranulation,moderate anti-PAF activity and decreased potency on hERG compared to astermizole.Hence compound 17d could serve as anti-allergic agent for further development.     

Synthesis and biological evaluation of piperidyl benzimidazole carboxamide derivatives as potent PARP-1 inhibitors and antitumor agents

We have synthesized a series of compounds based on a piperidyl benzimidazole carboxamide structure,and tested their PARP-1 inhibitory activity,as well as cellular inhibitory activity.Some of them show great potency as PARP-1 inhibitors and antitumor activity,which are valuable for further research.In addition,the predicted ADME properties and proposed binding mode with PARP-1 of the compounds were obtained via computational simulation.     

Facile synthesis of benzimidazole bearing 2-pyridone derivatives as potential antimicrobial agents

A series of benzimidazole bearing 2-pyridones 5a-k were synthesized and assessed in vitro for their activity as antimicrobial agents using the conventional broth dilution method. The results of the antimicrobial study revealed that compounds 5b, 5c, Sj and 5k exhibited substantial antibacterial activity while compound 5d emerged as amore potent antifungal agent compared to the standard drugs chloramphenicol and ketoconazole, respectively. It was observed that the presence of inductively electron withdrawing groups remarkably enhance the antibacterial activity of the newly synthesized compounds. Cytotoxicity studies suggested that none of the tested compounds exhibited any significant cytotoxic effects.     

Synthesis of polycyclic fused benzimidazole derivatives

Am easy method for the synthesis of tetraeyclie systems containing an imidazole and an iso-thiazole or an imidazole and a thiazine ring, by reacting 2H-1,3-benzothiazine-2-thion-4(3H)one with aromatic primary diarnines is reported. The structures were assigned based upon mass spectra and modes of cleavage of the compounds. The most important fragments are described.     

Synthesis of new 1,2,3-triazole linked benzimidazole molecules as anti-proliferative agents

One pot click chemistry is used to link triazole and benzimidazole pharmacophore to get N-((1-((1H-benzo[d]imidazol-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)aniline and its derivatives. Flexible linkages in the form of –CH₂–R or –O–R/–N–R were designed during synthesis. All the newly synthesized compounds were characterized by FT-IR and NMR spectroscopy as well as high-resolution mass spectrometry. Selected compounds were screened for in vitro anti-proliferative activity using National Cancer Institute (NCI)-60 human tumor cell line screening program. The most potent structure N-((1-((1H-benzo[d]imidazol-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-4-chloroaniline 7e showed 40% growth inhibition in renal cancer cell line (UO-31) at 10?µM concentration.     

Novel benzimidazole derivatives as anti-cervical cancer agents of potential multi-targeting kinase inhibitory activity

Multi-target EGFR, HER2, VEGFR-2 and PDGFR is an improved strategy for the treatment of solid tumors. This work deals with synthesis of an array of new 6-benzoyl benzimidazole derivatives utlizing1-(6-benzoyl-2-(3,4-dimethoxyphenyl)-1H benzo[d] imidazol-1-yl)propan-2-one (1) as a starting compound. The new compounds were screened as cytotoxic agents against cervical cancer cells (Hela) and Doxorubicin served as a reference drug. Most of the tested compounds showed promising anticancer activity in addition to their safety towards the normal cell line. The most potent candidates were evaluated as EGFR, HER2, PDGFR-β and VEGFR2 inhibitors in comparison to Erlotinib. Compounds 9 and 13 exhibited promising suppression effects. Also, the latter compounds exhibited their ability to induce cellular apoptosis alongside cell cycle arrest at the G2/M phase and accumulation of cells in pre-G1 phase. Molecular docking analysis suggested that compounds 2c, 3f, 9, 12 and 13 tightly interacts with the amino acid residues in the active binding site of HER2 kinase.     

Synthesis of trimethylhydroquinone derivatives as anti-allergic agents with anti-oxidative actions

A novel series of trimethylhydroquinone derivatives was synthesized and evaluated for their anti-lipid peroxidation activity in rat liver microsomes, inhibition of rat basophilic leukemia-1 (RBL-1) cell 5-lipoxygenase and 48 h homologous passive cutaneous anaphylaxis (PCA) activity in rats. 4-[4-[4-(Diphenylmethyl)-1-piperazinyl]-butoxy]-2,3,6-trimethyl phenol (9c) exhibited the ability to inhibit Fe(3+)-ADP induced NADPH dependent lipid peroxidation (IC50 = 5.3 x 10(-7) M), 5-lipoxygenase ((IC50 = 3.5 x 10(-7) M) and PCA reaction (57% inhibition at 100 mg/kg p.o.).     

Synthesis and evaluation of 5-aminimidazole-4-carboxamide riboside derivatives as anti-fatigue agents

Fatigue has a negative influence on daily life and work, and serious or chronic fatigue can even cause health problems. Studies have shown that 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) can exert anti-fatigue effects by activating AMP-activated protein kinase (AMPK). In this study, six AICAR derivatives with substitution at the hydroxyl sites of the ribose moiety were synthesized and evaluated as anti-fatigue agents. All of the derivatives were demonstrated to effectively resist fatigue in animal models. The mice treated with the optimal compound ZHM-01 showed an 8.6-fold greater exhaustion distance in the running wheel test and a 5.1-fold greater exhaustion time in the weight-loaded swimming test than those of the blank control group. ZHM-01 treatment also reduced lactic acid (LA) and blood urea nitrogen (BUN) accumulation during exercise. In addition, ZHM-01 administration enhanced the phosphorylation of AMPK but did not excite the central nervous system. Moreover, ZHM-01 showed good biological safety in a 21-day toxicity evaluation. This study provides a new reference for the development of treatments for fatigue-related health problems.