CsF�CCelite catalyzed facile N-alkylation of 2(3H)-benzoxazolones and antimicrobial properties of 2-substituted benzoxazole and 3-substituted-2(3H)-benzoxazolone derivatives

The synthesis and antimicrobial activity studies of a new series of cyclic amine containing benzoxazoles and benzoxazolone-2(3H)-ones derivatives were described. The alkylation of benzoxazolone was carried out using cesium fluoride–Celite. The newly synthesized compounds with the influence of the induction of the cyclic amine moiety in the benzoxazole scaffold have been evaluated with respect to the antibacterial and antifungal activity. The 2-cyclic amine-1,3-benzoxazoles (5a–l), 5-chloro-3-alkyl substituted-1,3-benzoxazol-2(3H)-ones (8a–f), and 3-[3-(cyclic amine)propyl]-1,3-benzoxazol-2(3H)-ones (9a–f) were synthesized. These derivatives were tested for antibacterial and antifungal activity. Among the compounds tested, 8c and 9f showed moderate to good antibacterial and antifungal activity. Compound 8a showed good antifungal activity.     

In vitro evaluation of the antibacterial and antifungal activity of some new pyrazolyl-quinazolin-4(3<Emphasis Type="Italic">H</Emphasis>)-one derivatives

Several pyrazolyl-quinazolin-4(3H)-ones 6a–m were synthesized by the cyclization of acrylamides 5a–m with hydrazine hydrate. The overall reaction was carried out by multi step process. The base-catalyzed cyclization of acid chloride 1 with 5-iodo anthranilic acid yielded benzoxazinone 2, which on reaction with hydrazine hydrate afforded amino quinazolin-4(3H)-one 3. The acrylamides 5a–m were easily synthesized by acetylation and then condensation with aromatic aldehyde of quinazolin-4(3H)-one 3. The structural confirmation of the synthesized compounds was carried out on the basis of elemental analyses as well as IR and NMR spectral results. The title compound 6a–m was evaluated for antibacterial and antifungal activity in vitro.     

Synthesis and cytotoxicity of 1-phenylethanolamine carboxamide derivatives: effects on the cell cycle

Seven novel analogues of 1-phenylethanolamine carboxamide derivatives, 3a–3g, related to carboxamides isolated from Isodon excisus were synthesized and evaluated for their cytotoxic and apoptosis-induction properties against murine B16 and leukemia L1210 cell lines. Compounds containing no substitution at the 4′-position (3a–3d) or containing a 4′-amino (3e–3g) group were investigated. Generally, the amino-containing compounds were slightly more active than their unsubstituted congeners. Also, the indole-containing compounds 3c and 3f gave the strongest cytotoxic activity (IC₅₀ = 25–87 μM) against the growth of L1210 and B16 cancer cells. Compound 3f was subjected to flow cytometry studies and it was found to induce L1210 cells grown in culture to undergo apoptosis.     

Synthesis and preliminary evaluation of 2-substituted-1,3-benzoxazole and 3-[(3-substituted)propyl]-1,3-benzoxazol-2(3H)-one derivatives as potent anticancer agents

The synthesis and cytotoxic activity studies of a new series of cyclic amine containing benzoxazole and benzoxazolone derivatives are described. The 2-cyclic amine-1,3-benzoxazoles 5a–k, 5-chloro-3-(3-chloropropyl)-1,3-benzoxazol-2(3H)-one 8 and 3-[3-(cyclic amino)propyl]-1,3-benzoxazol-2(3H)-ones 9a–f were synthesized. The newly synthesized compounds with the influence of the presence of cyclic amine moiety in the benzoxazole scaffold have been evaluated with respect to their cytotoxic effect toward four human cancer cell lines. The new compounds were evaluated to see whether substitution at the second and third position of the benzoxazole motif influence their cytotoxic effect toward cancer cells.     

Synthesis and preliminary evaluation of selected 2-aryl-5(6)-nitro- 1<Emphasis Type="Italic">H</Emphasis>-benzimidazole derivatives as potential anticancer agents

In this study we report the synthesis and preliminary evaluation of a series of six 2-aryl-5(6)-nitro-1H-benzimidazole derivatives (1–6) as potential anticancer agents. Cytotoxicity was evaluated against seven human neoplastic cell lines using the MTT assay. Compound 6 [2-(4-chloro-3-nitrophenyl)-5(6)-nitro-1H-benzimidazole] was the most active of the series, showing an IC₅₀ of 28 nM against the A549 cell line. This compound displayed a selective in vitro cytotoxic activity index (>700) in non neoplastic HACAT cells (IC₅₀ = 22.2 μM). Compounds 3 and 6 induce arrest in the S phase of the cell cycle, and compounds 1–6 induce apoptosis in the K562 cell line. Compound 6 induces poly (ADP-ribose) polymerase (PARP) inhibition activity as a potential mechanism of action. These results suggest that compound 6 could be a potent anticancer agent. Compound 3 displayed the best inhibitory activity against PARP with an IC₅₀ value of 0.05 μM, compared to the activity shown by the positive control 3-aminobenzamide (IC₅₀ = 28.5 μM).     

Design, synthesis, antifungal activity, and ADME prediction of functional analogues of terbinafine

From the earlier quantitative structure–activity relationship (QSAR) and molecular modeling studies, a series of quinoline derivatives 5a–h mimicking terbinafine and containing different bulky aromatic rings in the side chain were designed using LeapFrog, a de novo drug design program. The designed compounds were synthesized and screened for antifungal activity in vitro against C. albicans. Of the ten compounds designed and synthesized, compounds 5c, d, f, h, and i exhibited minimum inhibitory concentration (MIC) in the range 4–25 μg/ml and were further evaluated for oral toxicity in animal model. The pharmacokinetic properties for these compounds were estimated in silico and compared with terbinafine. Compound 5h, N-methyl-N-[(2-naphthyl)methyl]-8-quinolinemethanamine, was found to be least toxic, possessing pharmacokinetic parameters close to those of terbinafine.     

Potential anti-inflammatory activity and ulcerogenicity study of some novel pyrimido[4′,5′:4,5]pyrimido[1,6-<Emphasis Type="Italic">a</Emphasis>]azepine derivatives

A series of novel tricyclic pyrimido[4′,5′:4,5]pyrimido[1,6-a]azepine derivatives were synthesized using the starting compound 3-amino-1-oxo-2-phenyl-5-(pyrrolidin-1-yl)-1,2,4a,5,6,7,8,9-octahydropyrimido[1,6-a]azepine-4-carbonitrile 4. This series includes the 3-aryl derivatives 6a, b, the 3-cycloaminoalkyl derivatives 8a–f, the 3-mercaptomethyl derivatives 10 and 11a, b, the 2-cycloaminomethyl derivatives 13a–c, the 1-cycloamino derivatives 15a–c and the 1-amino derivative 16. The structures of the newly synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, mass spectroscopy and elemental analyses. The anti-inflammatory activity of all newly synthesized compounds was evaluated using the carrageenan-induced paw oedema test in rats using diclofenac sodium as the reference drug. Ulcer indices for the most active compounds were calculated. The 3-mercaptomethylacetic acid derivative 10 was the most active compound, showing activity comparable to diclofenac sodium with minimal ulcerogenic effect while the rest of the tested compound exhibited moderate anti-inflammatory activity.     

Conventional and microwave-assisted synthesis of imidazole and guanidine derivatives and their biological evaluation

A number of imidazole derivatives 3a–f and 4a–f have been synthesized by the condensation of 3-methylthiophen-2-carboxaldehyde 1a, 5-methylthiophen-2-carboxaldehyde 1b, N-methylpyrrol-2-carboxaldehyde 1c, 1-naphthaldehyde 1d, 2-naphthaldehyde 1e, and 2-hydroxy-1-naphthaldehyde 1f with 1,2-diaminoanthraquinone 2a and 2,3-diaminophenazine 2b, respectively. Condensation of 2-guanidinobenzimidazole with functionalized aldehydes 1a–f leads to the formation of guanidine derivatives 5a–f. Both imidazole (3a–f, 4a–f) and guanidine derivatives (5a–f) were synthesized in good yields using conventional heating and microwave irradiation techniques. Structures assigned to compounds 3a–f, 4a–f and 5a–f are supported by correct spectral and analytic data. On screening for anti-inflammatory and anticancer activities, compounds 3e, 4a and 5a exhibited good anti-inflammatory and compounds 3d, 3f, 4d and 4f showed very good anticancer activity.     

Iodine (III)-mediated synthesis of some 2-aryl/hetarylbenzoxazoles as antibacterial/antifungal agents

Ten 2-aryl/hetarylbenzoxazoles (5a, 5b, and 6a–h) were synthesized via oxidative cyclization of Schiff bases (3a, 3b, and 4a–h) with 1.1 equivalent of iodobenzene diacetate (IBD) in methanol. All of these 2-aryl/hetarylbenzoxazoles (5a, 5b, and 6a–h) were tested in vitro for their antibacterial and antifungal activities against Bacillus subtilis, Bacillus stearothermophilus, Escherichia coli, and Pseudomonas putida. These compounds also were screened for their antifungal activity against Aspergillus flavus and Aspergillus niger. Biological activity of these compounds was compared with those of commercially available antibiotics, chloramphenicol and antifungal agent cycloheximide. Most of these compounds, 5a, 5b, 6a, 6b, 6d, 6e, 6g, 6h, were equipotent or more potent than these commercial drugs at concentration 100 μg/ml.     

In vivo peritoneal antiangiogenesis and in vitro antiproliferative properties of some bischalcone derivatives

In this study, three, bisarylidene cyclopentanones (curcumin analogs) 3a–c are synthesized by Claisen Schmidt condensation reaction. Antiangiogenic effects of the compounds were studied in Ehrlich ascites tumor (EAT) cells transplanted mouse in vivo. Antiangiogenic effect of 3a–c showed reduction in ascites volume, cell number, and induced apoptotic bodies in EAT cells in tested animals. The antiproliferative effects of the 3a–c were determined at different concentrations by MTT assay on HepG2 and HeLa cells. The compounds showed significant antiproliferative activity at 40 μM concentration. Compound 3a (fluoro derivative) showed highest antiproliferative effect with the IC50 value 39 and 48 μm for HeLa and HepG2, respectively. Growth inhibition of the HeLa cells and antiangiogenesis was mediated by promoting apoptosis which was confirmed by DNA fragmentation study.     

Design and synthesis of novel N-substituted-3-chloro-2-azetidinone derivatives as potential anticonvulsant agents

Abstract  

A new series of N-[3-chloro-2-(substitutedphenyl)-4-oxo-azetidin-1-yl]isonicotinamide (2a–l) were synthesized through condensation reaction of isoniazide with substituted aldehyde. The newly synthesized compounds were characterized by spectral data (IR, ¹H NMR, mass spectra) and elemental analysis. Compound 2e exhibited excellent anticonvulsant activity and no neurotoxicity in comparison to reference drug phenytoin.     

Synthesis,in vitro cytotoxicity,and anti-microbial studies of 1,4-bis(4-substituted-5-mercapto-1,2,4-triazol-3-yl)butanes

Synthesis and evaluation of cytotoxicity and anti-microbial activity of a series of 1,4-bis(4-substituted-5-mercapto-1,2,4-triazol-3-yl)butane derivatives comprising thioether functionality and other pharmacophore modifications are described. All the newly synthesized compounds were characterized by IR, NMR, elemental analyses, and mass spectral studies. The compounds 4a–f, 5a–f, and 6a–f were evaluated for in vitro cytotoxicity potential using the standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against a panel of three human cancer cell lines: Lung carcinoma A-549, Colon carcinoma HT-29, and Breast Cancer MDA MB-231. All the compounds were subjected to in vitro anti-bacterial activity against Bacillus subtilus (ATCC 6633), Staphylococcus aureus (ATCC-25923), Escherichia coli (ATCC-25922), and Pseudomonas aeruginosa (ATCC-27853) and their minimal inhibitory concentrations were determined.     

17-Oximino-5-androsten-3��-yl esters: synthesis, antiproliferative activity, acute toxicity, and effect on serum androgen level

Abstract  

The 17-oximino-5-androsten-3β-yl esters (10a–10j) were synthesized from commercially available (25R)-5-Spirosten-3β-ol (Diosgenin) (4) as starting material. The synthesized compounds were evaluated for their antiproliferative activity against prostate specific cancer cell line DU-145, acute toxicity, and effect on serum androgen level and were compared with Finasteride used as positive control. Some of the compounds exhibited better cytotoxicity and antiandrogenic activity than the reference control. The detailed synthesis, spectroscopic data, and biological evaluation for the synthesized compounds are reported.     

Studies on fused heterocyclic 3,6-disubstituted-1,2,4-triazolo-1,3,4-thiadiazoles: synthesis and biological evaluation

In this study, a series of 3,6-disubstituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles (5a–t) were synthesized by condensing 4-amino-3-mercapto-(4H)-1,2,4-triazoles (4a–c) with different aromatic or aroyl acids through one-pot reaction. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic, and lipid peroxidation actions. Some of the newly synthesized compounds showed very good anti-inflammatory activity with low GI toxicity and reduced lipid peroxidation. These compounds also showed interesting profile of analgesic activity in acetic acid-induced writhing test. The findings of the study indicate that the synthesized compounds have superior GI safety profile along with reduction in lipid peroxidation as compared to that of the standard.     

Synthesis and anti-HIV evaluation of the novel 2-(m-chlorobenzyl)-4-substituted-7-methyl-1, 1, 3-trioxo-pyrazolo[4, 5-e] [1, 2, 4]thiadiazines

A novel series of 2-(m-Chlorobenzyl)-4-substituted-1, 1, 3-trioxo-2H,4H-pyrazolo[4, 5-e][1, 2, 4] thiadiazines (7a-k) were synthesized, and evaluated for their anti-HIV replication in MT-4 cell cultures. Compound (7a) showed activity against HIV-1-induced cytopathicity, with an EC₅₀ value of 45.6 μM, but none of the compounds exhibited inhibitory activity against HIV-2.     

Synthesis and biological activity of novel 1H-1,4-diazepines containing benzene sulfonyl piperazine moiety

The synthesis of biologically active 1H-1,4-diazepines 6a–e in good yield, from the heterocyclization reaction of [N ⁴-(4-acetylamino) benzene sulfonyl) piperazinyl-N ¹-propyl]-1,3-dialkyl/aryl propane-1,3-dione 5a–e and ethylenediamine (EDA) in the presence of silica sulphuric acid (SSA) is described. The novel β-diketones/β-ketoesters 5a–e were synthesized by the condensation reaction of [N ⁴-(4-acetylamino) benzene sulfonyl) piperazinyl-N ¹-1-bromopropane with various β-diketones/β-ketoesters 4a–e. All structures of the newly synthesized compounds were elucidated by elemental analysis and spectral studies. The compounds 6a–e have been screened for antimicrobial, antifungal and anthelmintic activity.     

Synthesis,antiproliferative activity,acute toxicity and assessment of the antiandrogenic activities of new androstane derivatives

A number of 17-oxo-5-androsten-3β-yl esters (9a–9f) and 3β-alkoxy-5-androsten-17-ones (11a–11e) were synthesized from commercially available (25R)-5-spirosten-3β-ol (Diosgenin) (4) as starting material. The synthesized compounds were evaluated for their antiproliferative activity against the prostate-specific cancer cell line DU-145, acute toxicity and effect on serum androgen levels, and compared with finasteride as positive control. Some of the compounds exhibited better cytotoxicity and antiandrogenic activity than the reference control. The detailed synthesis, spectroscopic data and biological activity of the synthesized compounds are reported.     

Design, synthesis and preliminary evaluation of some novel [1,4]diazepino [5,6-b]pyrrolizine and 6-(2-oxopyrrolidino)-1H-pyrrolizine derivatives as anticonvulsant agents

New series of diazepino[5,6-b]pyrrolizines 7a–c and 8a–c and 6-(2-oxopyrrolidino)-1H-pyrrolizines 10a–c were synthesized through acylation of the key aminonitrile derivatives 5a–c (Scheme 1) with the appropriate acid chlorides. Subsequent cyclization reaction yielded the target compounds (Schemes 2, 3). The chemical structure of the synthesized compounds was elucidated by spectral and elemental analyses. The synthesized compounds were evaluated for their ability to protect mice against PTZ-induced seizures, the most active compounds were 10a–c where compound 10b exhibited 67.9% relative potency compared to phenobarbitone and compound 10a provided the maximum protection % of all compounds (60%) at dose of 50 mg/kg comparable to phenobarbitone at a dose of 20 mg/kg.     

Antituberculosis activity of hydrazones derived from 4-fluorobenzoic acid hydrazide

A series of substitututed methylene/ethylene 4-fluorophenylhydrazide derivatives (3a–p) was synthesized with the aim of evaluating their antimycobacterial activity toward a strain of Mycobacterium tuberculosis H37Rv. Their chemical structures were confirmed by ¹H-nuclear magnetic resonance (NMR) and electrospray mass spectrometry (ES-MS) spectral data, and elemental analysis. The in vitro antimycobacterial evaluation was performed according to the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF) antituberculosis drug discovery program. Compound 3a, 4-fluorobenzoic acid [(2,6-dichlorophenyl) methylene]hydrazide, showed the highest inhibitory activity of all the compounds under study.     

Quinolinedione nucleus as a novel scaffold for A1 and A2A adenosine receptor antagonists

In the last few years, much effort has been directed towards the synthesis of selective adenosine receptor (AR) antagonists since they are attractive tools for pharmacological intervention in many pathophysiological conditions. During our studies aimed at obtaining new nonclassical adenosine antagonists devoid of phosphodiesterase (PDE) inhibition, a series of 2-pyridones and 2,5-quinolinediones (3a–f, 5a–f, 6a,c–f) has been synthesized as potential AR ligands. Binding affinities of the new compounds were determined for bovine and human adenosine A₁, A_2A, and A₃ receptors. Compound 5f showed good affinity (K _i = 7.8 μM) towards human A₁AR but no selectivity (K _i = 7.0 μM) towards human A_2AAR, whereas compound 6f showed more affinity towards human A_2A (K _i = 16 μM) than A₁ receptor (percentage inhibition at 10 μM concentration = 11). In the 1–100 μM range, the new compounds did not inhibit cardiac PDE3 activity at all. Molecular modeling studies carried out on 5f and 6f support the pharmacological results and suggest 6f as a potential lead compound selective towards A_2AAR.