Synthesis of novel selenium containing sulfa drugs and their antibacterial activities

Synthesis of 3-[4-(N-substituted sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyri-do[3′,2′:4,5]selenolo[3,2-d]pyrimidines,7-[4-(N-substituted sulfamoyl)phenyl]-7,8-dihydro-8-oxo-3,4-diphenylpyrimido[4′,5′:4,5]selenolo [2,3-c]pyridazines and 1-[4-(N-substituted sulfamoyl)phenyl]-1,11-dihydro 11-oxo-4-methylpyrimido[4′,5′:4,5]selenolo[2,3-b]quinolines is reported. 4-Amino-N-pyrimidine-2-ylbenzene sulfonamide (a), 4-amino-N-(2,6-dimethylpyrimidin-4-yl)benzene sulfonamide (b), N-[(4-aminophenyl)sulfonyl] acetamide (c) with N-ethoxymethyleneamino of selenolo pyridine, selenolo pyridazine and selenolo quinoline derivatives respectively were obtained starting from 1-amino-N ⁴-substituted sulfanilamides. Spectroscopic data (IR, ¹H NMR, ¹³C NMR and Mass spectral) confirmed the structure of the newly synthesized compounds. Substituted pyrimidines, pyridazines and quinolines were screened for antibacterial activity against gram-positive and gram-negative bacteria. Selenolo derivative of N-[(4-aminophenyl)sulfonyl] acetamide (substitutent of sulfacetamide c) showed strong bactericidal effect against all the tested organisms. Selenolo[3,2-d]pyrimidin (substitutent a) showed a good bactericidal effect against Serratia marcescens, Staphylococcus aureus and Escherichia coli. Compounds selenolo[2,3-c]pyridazine (substitutent b), selenolo[2,3-b]quinoline(substitutents c)) exhibited a moderate bactericidal effect against Serratia marcescens. None of the synthesized seleno pyridazines has a considerable antimicrobial activity against the tested organisms. The minimum inhibitory concentration (MIC) of the most active compound-3-[4-(N-acetyl sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyrido[3′,2′:4,5]selenolo [3,2-d]pyrimidine was 10 mg ml⁻¹.     

Synthesis,anticancer assessment on human breast,liver and colon carcinoma cell lines and molecular modeling study using novel pyrazolo[4,3-c]pyridine derivatives

The key intermediate 3-aminopyrazolo[4,3-c]pyridine-4,6-dione (2) is considered as a precursor for some novel pyrazolo[4,3-c]pyridines 4a-c, arylhydrazopyrazolo[4,3-c]pyridines 8a-e, pyrazolo[4,5,1-ij][1,6]naphthyridines 11a-e and pyrido[4′,3′:3,4]pyrazolo[1,5-a]-pyrimidines 15a-d through Knovenegal condensation, coupling reaction and Michael addition. Some of the newly synthesized pyrazolo[4,3-c]pyridine derivatives were investigated for anticancer activity. The results of the cytotoxic activity revealed that compound 6b was the most active compound against the breast and liver carcinoma cell lines which gives IC₅₀ values of 1.937 and 3.695 µg/mL, respectively compared to reference drug (doxorubicin) with IC₅₀ values of 2.527 and 4.749 µg/ml, respectively. Moreover, compound 6c was potent compound against the colon carcinoma cell line which gives the value of IC₅₀ = 2.914 µg/ml compared to doxorubicin with IC₅₀ value of 3.641 µg/ml. Some selected of the novel synthesized compounds were docked inside the active site of ERK2 enzyme and were found display a suitable binding with the active site amino acids according to their bond lengths, angles and conformational energy.     

Synthesis and biological activity of pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives: in silico approach

Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56?µg, 3g: 2.337?µg, allopurinol: 1.816?µg) and IC₅₀ (3b: 4.228?µg, 3g: 3.1?µg, allopurinol: 2.9?µg) values. The enzyme–ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (?84.976?kcal/mol) and 3g (?90.921?kcal/mol) compared with allopurinol (?55.01?kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2–a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.     

Synthesis of novel 1,2,3-triazole tagged pyrazolo[3,4-b]pyridine derivatives and their cytotoxic activity

A series of novel 1,2,3-triazole tagged pyrazolo[3,4-b]pyridine derivatives 3 and 4 were prepared respectively starting from 6-phenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 1 via selective N-propargylation, followed by reaction with diverse substituted alkyl/perfluoroalkyl/aryl/aryl amide azides under Sharpless conditions. All the synthesized compounds 3 and 4 were screened for cytotoxic activity against four human cancer cell lines such as U937, THP-1, HL60 and B16-F10. Compounds 3e, 4g, 4i and 4j which showed promising activity have been identified.     

Design and synthesis of 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles and pyrazolo[3,4-b]pyridines for Aurora-A kinase inhibitors

Two series of 3-aminopyrazole compounds including 24 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles and 16 pyrazolo[3,4-b]pyridines were synthesized and evaluated against HCT116, A549, and A2780 tumor cell lines. Among them, three compounds were found to have the ideal anti-proliferative activities in vitro. Docking experiments showed that the novel pyrazolo[3,4-b]pyridines share the similar interaction mode with Aurora-A kinase as PHA739358.     

Synthesis and Antiviral Evaluation of Some Novel Tricyclic Pyrazolo[3,4‐b]indole Nucleosides

Novel pyrazolo[3,4‐b]indole nucleoside analogs were synthesized from the corresponding 3‐formyl‐2‐chloroindole and 3‐cyano‐2‐chloroindole nucleosides by treatment with hydrazine. Very few examples of pyrazolo[3,4‐b]indole heterocycles have been published in the literature and this is the first synthesis of nucleoside analogs containing this heterocycle. These new pyrazolo[3,4‐b]indole nucleosides were active against human cytomegalovirus and herpes simplex virus type 1, but this activity was not well separated from cytotoxicity.     

Synthesis and biological evaluation of novel alkyl amide functionalized trifluoromethyl substituted pyrazolo[3,4-b]pyridine derivatives as potential anticancer agents

A series of novel alkyl amide functionalized trifluoromethyl substituted pyrazolo[3,4-b]pyridine derivatives 5, 6 and 7 were prepared starting from 6-phenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 3 via selective N-alkylation, followed by reaction with different primary aliphatic amines, cyclic secondary amines or l-amino acids under different set of conditions. All the synthesized compounds 5, 6 and 7 were screened for anticancer activity against four cancer cell lines such as A549—Lung cancer (CCL-185), MCF7—Breast cancer (HTB-22), DU145—Prostate cancer (HTB-81) and HeLa—Cervical cancer (CCL-2). The compounds 5i and 6e are found to have promising bioactivity at micro molar concentration.     

Design and Synthesis of Indole and Tetrahydroisoquinoline Hydantoin Derivatives as Human Chymase Inhibitors

The synthesis of new potential inhibitors of human chymase is described. Treatment of dihydroimidazo[1,5-a]indole and [1,5-b]isoquinoline-dione with thioaryl followed by oxidation gave the N-arylsulfonylmethyl of polycyclic hydantoin derivatives 3, 5 and 6.     

Synthesis,cytotoxicity, antimicrobial and anti-biofilm activities of novel pyrazolo[3,4-b]pyridine and pyrimidine functionalized 1,2,3-triazole derivatives

A series of novel pyrazolo[3,4-b]pyridine and pyrimidine functionalized 1,2,3-triazole derivatives 8a–g and 9a–g were prepared starting from 6-trifluoromethylpyridine-2(1H)one 2 via selective O-alkylation, followed by cyclisation using hydrazine hydrate to obtain 6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 4. Compound 4 was diazotized followed by reaction with sodium azide, resulted in 3-azido-6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridine 5. Compound 5 was further cyclized with N-/O-propargylated pyrimidine derivatives under Sharpless conditions and obtained compounds 6 and 7, respectively. Each set of compounds 6 and 7 were alkylated with different alkyl halides and obtained respective products 8 and 9. All the products were screened for cytotoxicity against four human cancer cell lines such as A549-Lung (CCL-185), MCF7-Breast (HTB-22), DU145-Prostate (HTB-81) and HeLa-Cervical (CCL-2), compounds 9d, 9e and 9f which showed promising activity have been identified. The products were also screened for antimicrobial, anti bio-film and MBC activities. Promising compounds in each case have been identified.     

Ring Opening Reaction of Pyrazolo[3,4-c]Maleimide Nucleosides

Abstract

Synthesis of pyrazolo[3,4-c]maleimide nucleosides was attempted, but ring opening reaction of the maleimide part was observed during ammonolysis of sugar-protected pyrazolo[3,4-c]maleimide nucleosides. The isolated pyrazole nucleosides were characterized by NMR spectra and X-ray analysis.     

Synthesis and in vitro antimicrobial activity of novel N-(6-chlorobenzo[d]thiazol-2-yl) hydrazine carboxamide derivatives of benzothiazole class

In this study, a series of novel 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole (6a–g) and 1,3,4-oxadiazole (7a–g, 8) were synthesized from N-(6-chlorobenzo[d]thiazol-2-yl) hydrazine carboxamide derivatives of benzothiazole class. Antimicrobial properties of the title compound derivatives were investigated against one Gram (+) bacteria (Staphylococcus aureus), three Gram (?) bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and five fungi (Candida albicans, Aspergillus niger, Aspergillus flavus, Monascus purpureus and Penicillium citrinum) using serial plate dilution method. The investigation of antibacterial and antifungal screening data revealed that all the tested compounds showed moderate to good inhibition at 12.5–100?µg/mL in DMSO. It has been observed that triazolo-thiadiazole derivatives are found to be more active than 1,3,4-oxadiazole derivatives against all pathogenic bacterial and fungal strains.     

Synthesis and Biological Evaluation of Thienopyrrolizines,a New Family of CDK/GSK-3 Inhibitors

Fifteen new thieno[2,3-b]- and thieno[3,4-b]pyrrolizines were synthesized and tested against two protein kinases, CDK1/cyclin B and GSK-3. Among these compounds, 3-(3-hydroxy-4-methoxyphenyl)-8H-thieno[2,3-b]pyrrolizin-8-one 4g was identified as a moderate inhibitor of these kinases. Its molecular modeling study brought to the fore the pivotal role of the 2-methoxyphenol grouping and the interest in replacing it by bioisosteric moieties in future pharmacomodulations.     

A convenient synthesis and molecular modeling study of novel pyrazolo[3,4-d]pyrimidine and pyrazole derivatives as anti-tumor agents

Abstract

An efficient method to obtain ethyl 5-amino-1-tosyl-1H-pyrazole-4-carboxylate (3) was outlined using condensation reactions of 4-methylbenzenesulfonylhydrazide with (E)-ethyl 2-cyano-3-ethoxyacrylate. The cyclocondensation reaction of this substrate and its hydrazide derivative with urea, thiourea, formamide, formic acid, d-glucose, o-phenylenediamine, 4-dimethylaminobenzaldehyde, anthracene-9-carbaldehyde, thioglycolic acid and carbon disulphide then with hydrazine hydrate analogues furnished a series of pyrazolo[3,4-d]pyrimidine, pyrazolo[3,4-d]oxazin-4-one, pyrazole-4-glucoside, 4-benzo[d]imidazole, 1,3-thiazolidinone, 1,3,4-oxadiazol-2(3H)-thione and 1,2,4-triazol-5(4H)-thione derivatives respectively. The structure of the compound 3 was supported by X-Ray crystallographic data. Orally administrated, one of each of the series of pyrazoles showed significant effects in mouse tumor model cancer cell lines (EAC) and two human cancer cell lines of Colon cancer (HCT-29) and Breast cancer (MCF-7) with docking studies.     

Synthesis and antimycobacterial evaluation of various 6-substituted pyrazolo[3,4-d]pyrimidine derivatives

Various pyrazolo[3,4-d]pyrimidines carrying a variety of substituents in the 6-position have been synthesised and their ability to inhibit growth of Mycobacterium tuberculosis in vitro has been determined. Compounds 5a, 5b, 6c, 7a, 7b, 8d, 8e and 8f demonstrated a minimum inhibitory concentration (MIC) of <6.25?µg/mL and were found to be active against Mycobacterium tuberculosis strain H₃₇RV. Compound 8d was found to be the most active compound in vitro with a MIC of <6.25?µg/mL and inhibitory concentration IC₉₀ of 1.53?µg/mL.     

Acyclo C-Nucleoside Analogs. Regioselective Annellation of a Triazole Ring to 5-Methyl-1,2,4-Triazino[5,6-b]Indole and Formation of Certain 3-Poly Hydroxyalkyl Derivatives

ABSTRACT

Cyclodehydrogenation of the ethylidene derivative of (5-methyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazine (1) gave the angular isomer, 1,10-dimethyl-1,2,4-triazolo[3′,4′:3,4][1,2,4]triazino[5,6-b]indole (4). The linear isomer, 3,10-dimethyl-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole (7) could be prepared regioselectively by the cyclodehydration of the acetyl derivative of 1. The cyclodehydrogenation was extended to the monosaccharide derivatives of 1. The role of the N-methyl group on the site of annellation has been discussed.     

Design,synthesis, cytotoxic evaluation,and QSAR study of some 6H-indolo[2,3-b]quinoxaline derivatives

In the pathway of anticancer drug development, we designed and synthesized some 6H-indolo[2,3-b]quinoxaline derivatives (which act as DNA intercalators) by structural modification. The structure of the 6H-indolo[2,3-b]quinoxaline derivatives was confirmed by IR, NMR, Mass and elemental analysis. The compounds (IDQ-5, IDQ-10, IDQ-11, IDQ-13, and IDQ-14) exhibited significant in vitro activity against a human leukemia (HL-60) cell line. The QSAR derived for modeling the cytotoxic activity of 6H-indolo[2,3-b]quinoxaline derivatives suggests that candidate structures for increased cytotoxic potency should incorporate cyclic substituents or substituents with primary carbon atoms.     

Thee-component,one-pot synthesis of hexahydroazepino[3,4-b]indole and tetrahydro-1H-pyrido[3,4-b]indole derivatives and evaluation of their cytotoxicity

A three-component, four-center Ugi reaction has been developed to produce a novel class of 2-aryl-3-oxo-hexahydroazepino[3,4-b]indole and 2-aryl-3-oxo-tetrahydro-1H-pyrido[3,4-b]indole derivatives in good to high yields. A few of them exhibit moderate cytotoxicity against various cancer cell lines such as HeLa (human epithelial cervical cancer), A549 (human lung carcinoma epithelial), DU145 (human prostate carcinoma epithelial) and MCF-7 (human breast adenocarcinoma).     

Design,synthesis of novel pyranotriazolopyrimidines and evaluation of their anti-soybean lipoxygenase,anti-xanthine oxidase,and cytotoxic activities

The synthesis of 14-(aryl)-14H-naphto[2,1-b]pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine-2-yl) acetamidoximes 2a–e has been accomplished by reaction of 2-acetonitrile derivatives 1a–e with hydroxylamine. Cyclocondensation reaction of precursors 2a–e with some elctrophilic species such as ethylorthoformate, acetic anhydride, and methyl-acetoacetate provided the new oxadiazole derivatives 3a–e, 4a–e, and 5a–e, respectively. On the other hand, the reaction of precursors 2a–e with 2-chloropropanoyl chloride afforded the new acetimidamides 6a–e which evolve under reflux of toluene to the new oxadiazoles 7a–e. The synthetic compounds were screened for their anti-xanthine oxidase, anti-soybean lipoxygenase, and cytotoxic activities. Moderate to weak xanthine oxidase and soybean lipoxygenase inhibitions were obtained but significant cytotoxic activities were noted. The most cytotoxic activities were recorded mainly (i) 5a was the most active (IC_50?=_?4.0?μM) and selective against MCF-7 and (ii) 2a was cytotoxic against the four cell lines with selectivity for MCF-7 and OVCAR-3 (IC_50?=_?17 and 12?μM, respectively) while 2e is highly selective against OVCAR-3 (IC_50?=_?10?μM).     

Synthesis of new 4-[2-(alkylamino)ethylthio]pyrrolo[1,2-a]quinoxaline and 5-[2-(alkylamino)ethylthio]pyrrolo[1,2-a]thieno[3,2-e]pyrazine derivatives,as potential bacterial multidrug resistance pump inhibitors

The synthesis of new 4-[2-(alkylamino)ethylthio]pyrrolo[1,2-a]quinoxaline derivatives 1a-l is described in five or six steps starting from various substituted nitroanilines 2a-e. The bioisostere 5-[2-(alkylamino)ethylthio]pyrrolo[1,2-a]thieno[3,2-e]pyrazine 1m was also prepared. The new derivatives were evaluated as efflux pump inhibitors (EPIs) in a model targeting the NorA system of Staphylococcus aureus. The antibiotic susceptibility of two strains overproducing NorA, SA-1199B and SA-1, was determined alone and in combination with the neo-synthesised compounds by the agar diffusion method and MIC determination, in comparison with reserpine and omeprazole taken as reference EPIs. A preliminary structure-activity relationship study firstly allowed to clarify the influence of the substituents at positions 7 and/or 8 of the pyrrolo[1,2-a]quinoxaline nucleus. Methoxy substituted compounds, 1b and 1g, were more potent EPIs than the unsubstituted compounds (1a and 1f), followed by chlorinated derivatives (1c-d and 1h). Moreover, the replacement of the N,N-diethylamino group (compounds 1a-e) by a bioisostere such as pyrrolidine (compounds 1f-h) enhanced the EPI activity, in contrast with the replacement by a piperidine moiety (compounds 1i-k). Finally, the pyrrolo[1,2-a]thieno[3,2-e]pyrazine compound 1m exhibited a higher EPI activity than its pyrrolo[1,2-a]quinoxaline analogue 1a, opening the way to further pharmacomodulation.     

N-aryl 2-aryloxyacetamides as a new class of fatty acid amide hydrolase (FAAH) inhibitors

Fatty acid amide hydrolase (FAAH) is a promising target for the development of drugs to treat neurological diseases. In search of new FAAH inhibitors, we identified 2-(4-cyclohexylphenoxy)-N-(3-(oxazolo[4,5-b]pyridin-2-yl)phenyl)acetamide, 4g, with an IC₅₀ of 2.6?µM as a chemical starting point for the development of potent FAAH inhibitors. Preliminary hit-to-lead optimisation resulted in 2-(4-phenylphenoxy)-N-(3-(oxazolo[4,5-b]pyridin-2-yl)phenyl)acetamide, 4i, with an IC₅₀ of 0.35?µM.