Anti-tubercular activity and molecular docking studies of indolizine derivatives targeting mycobacterial InhA enzyme.

A series of 1,2,3-trisubstituted indolizines (2a-2f, 3a-3d, and 4a-4c) were screened for in vitro whole-cell anti-tubercular activity against the susceptible H37Rv and multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains. Compounds 2b-2d, 3a-3d, and 4a-4c were active against the H37Rv-MTB strain with minimum inhibitory concentration (MIC) ranging from 4 to 32 µg/mL, whereas the indolizines 4a-4c, with ethyl ester group at the 4-position of the benzoyl ring also exhibited anti-MDR-MTB activity (MIC = 16-64 µg/mL). In silico docking study revealed the enoyl-acyl carrier protein reductase (InhA) and anthranilate phosphoribosyltransferase as potential molecular targets for the indolizines. The X-ray diffraction analysis of the compound 4b was also carried out. Further, a safety study (in silico and in vitro) demonstrated no toxicity for these compounds. Thus, the indolizines warrant further development and may represent a novel promising class of InhA inhibitors and multi-targeting agents to combat drug-sensitive and drug-resistant MTB strains.

Crystallography, in Silico Studies, and In Vitro Antifungal Studies of 2,4,5 Trisubstituted 1,2,3-Triazole Analogues.

A series of 2,4,5 trisubstituted-1,2,3-triazole analogues have been screened for their antifungal activity against five fungal strains, Candida parapsilosis, Candida albicans, Candida tropicalis, Aspergillus niger, and Trichophyton rubrum, via a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) microdilution assay. Compounds GKV10, GKV11, and GKV15 emerged as promising antifungal agents against all the fungal strains used in the current study. One of the highly active antifungal compounds, GKV10, was selected for a single-crystal X-ray diffraction analysis to unequivocally establish its molecular structure, conformation, and to understand the presence of different intermolecular interactions in its crystal lattice. A cooperative synergy of the C-H···O, C-H···N, C-H···S, C-H···π, and π···π intermolecular interactions was present in the crystal structure, which contributed towards the overall stabilization of the lattice. A molecular docking study was conducted for all the test compounds against Candida albicans lanosterol-14α-demethylase (pdb = 5 tzl). The binding stability of the highly promising antifungal test compound, GKV15, from the series was then evaluated by molecular dynamics studies.

Synthesis of lignan conjugates via cyclopropanation: Antimicrobial and antioxidant studies.

Ethyl 2-(4-methoxyphenyl)-3-(thiophene-2-carbonyl)cyclopropanecarboxylates 2(a-f) and ethyl 4-aryl-7-oxo-4,5,6,7-tetrahydrobenzo[b]thiophene-5-carboxylates 4(a-f) were synthesized by simple procedure. The synthesized new compounds were screened in vitro for their antimicrobial and antioxidant activities. The compounds 2b and 4f showed excellent antibacterial activity; while 2b and 4f showed remarkable antifungal properties. The results of antioxidant activity studies revealed that compounds 4b and 4f manifested profound antioxidant potential. The docking studies were done for the final compounds. The ADME result indicates that all these molecules possess pharmaceutical properties in the range of 95% of drugs.

Design, synthesis, characterization, and antibacterial activity of {5-chloro-2-[(3-substitutedphenyl-1,2,4-oxadiazol-5-yl)-methoxy]-phenyl}-(phenyl)-methanones.

In the present investigation, a series of novel {5-chloro-2-[(3-(substitutedphenyl)-1,2,4-oxadiazol-5-yl)-methoxy]-phenyl}-(phenyl)-methanones (3a-i) have been synthesized from 5-(chloromethyl)-3-substitutedphenyl-1,2,4-oxadiazole (2a-i). The newly synthesized compounds were characterized by IR, NMR (1H and 13C), mass spectral and elemental analysis. The title compounds were investigated for in-vitro qualitative (zone of inhibition) and quantitative (MIC) antibacterial activity by agar cup plate and microtitration methods, respectively. The minimum inhibitory concentration and structure activity relationships (SARs) were evaluated. Amongst the synthesized compounds in this series, {5-chloro-2-[(3-(2,5-difluoro-4-methyl-phenyl)-1,2,4-oxadiazol-5-yl)-methoxy]-phenyl}-(phenyl)-methanone (3d) was found to exhibit significant activity with MICs of 21.5, 22.4, 29.8 and 30.6 microg/mL against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae, respectively.

Synthesis of some novel 2-[2-(aroyl-aroxy)-methyl]-4-phenyl-1,3-thiazoles as potent anti-inflammatory agents.

A series of 2-[2-(aroyl-aroxy)-methyl]-4-phenyl-1,3-thiazoles 4a-j were obtained via multiple step synthesis sequence beginning with the hydroxybenzophenones (1a-g). Hydroxybenzophenones on reaction with chloroacetonitrile affords [(2-benzoyl) phenoxy] acetonitrile (2a-g), which reacts with H(2)S/NH(4)OH and yields [(2-benzoyl) phenoxy] acetothiamide (3a-g), which on treatment with phenacylbromides affords 2-[2-(aroyl-aroxy)-methyl]-4-phenyl-1,3-thiazoles (4a-j). All the newly synthesized compounds were evaluated for their anti-inflammatory activity and were compared with standard drugs. Of the compounds studied, (4g), compounds with chloro substituents showed more potent activity than the standard drug phenyl butazone at all doses tested.

Synthesis, characterization and antibacterial activity of 2-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazol-4-yl]-5-(substituted-phenyl)-[1,3,4]oxadiazoles.

In the present investigation a series of novel 2-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazol-4-yl]-5-(substituted-phenyl)-[1,3,4]oxadiazoles (4a-j) were synthesized by cyclization of substituted-benzoic acid N'-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazole-4-carbonyl]-hydrazide by using phosphorousoxychloride at 120 degrees C. The chemical structure of the newly synthesized compounds was characterized by analytical and spectral (IR, (1)H NMR, (13)C NMR and LC-MS) methods. The title compounds were screened for qualitative (zone of inhibition) and quantitative antibacterial activity (MIC) by agar cup plate and microtitration methods, respectively. Among the synthesized compounds in this series compound 2-[1-(5-chloro-2-methoxyphenyl)-5-methyl-1H-pyrazol-4-yl]-5-(4-fluorophenyl)-1,3,4-oxadiazole (4b) was found to exhibit significant antibacterial activity with MICs of 22.4, 29.8, 29.6 and 30.0 microg/mL against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae, respectively. The other compounds exhibited moderate activity when compared to standard substance Ampicillin.

Synthesis and antifungal activity of 2-azetidinonyl-5-(2-benzoylphenoxy)methyl-1,3,4-oxadiazoles against seed-borne pathogens of Eleusine coracana (L.) Gaertn.

BACKGROUND: Finger millet is a major food crop as well as feed and fodder for livestock, especially in regions of southern India. A sturdy crop to fluctuating environmental conditions, it can be cultivated in all seasons of the year. Leaf, neck and finger blast caused by Pyricularia grisea Sacc. and Bipolaris setariae (Saw.) Shoem, as well as leaf spot disease, Bipolaris nodulosa (Berk & M.A.Curtis) Shoem, are major production constraints in southern India. Apart from environmental conditions, the use of harvested seeds by farmers is a major reason for disease prevalence. Benzophenone analogues have been investigated for controlling phytopathogenic fungi. In addition, the most important applications of azetidin-2-ones are as antibiotics. Based on this information, the present study was conducted to explore the antifungal activity of integrated 2-azetidinonyl and 1,3,4-oxadiazoles moieties into a benzophenone framework. RESULTS: A simple high-yielding method for the integration of heterocyclic rings, namely 2-azetidinonyl, at the benzophenone nucleus has been achieved, starting from substituted 2-hydroxybenzophenones under mild conditions on a wet solid surface using microwave irradiation. In the present study, an array of newly synthesised compounds, 2-azetidinonyl-5-(2-benzoylphenoxy)methyl-1,3,4-oxadiazoles, were screened for their antifungal property against blast and leaf spot causing fungi associated with the seeds of finger millet, cv. Indof-9. CONCLUSION: Two of the newly synthesised compounds showed promising effects in depleting the incidence of seed-borne pathogenic fungi of finger millet. The suppression of Pyricularia grisea and Bipolaris setariae resulted in enhanced seed germination and seedling growth.

Synthesis and anti-inflammatory activity of 2-(2-aroylaroxy)-4,6-dimethoxy pyrimidines.

Reaction of 6a-f individually with 2-methylsulfonyl-4,6-dimethoxypyrimidine yielded 7a-f in excellent yield. The newly synthesized heterocycles were characterized by IR, (1)H NMR, and mass spectral data. Compounds 7a-f was screened for their anti-inflammatory activity and were compared with standard drugs. Of the compounds studied, the compound 7e showed more potent activity than the standard drugs at all doses tested.

Synthesis, docking and anti-tumor activity of beta-L-1,3-thiazolidine pyrimidine nucleoside analogues.

In the search for effective, selective, and nontoxic antiviral and antitumor agents, a variety of strategies have been devised to design nucleoside analogues. Here we have described the versatile synthesis of beta-L-1,3-thiazolidine nucleoside analogues. These analogues are all derived from the key stereochemically defined intermediate N-tert-butoxy-carbonyl-4-hydroxymethyl-1,3-thiazolidine-2-ol which was accessible in 57% yield starting from L-Cysteine methylester hydrochloride. N-tert-butoxycarbonyl-2-acyloxy-4-trityloxymethyl-1,3-thiazolidine was coupled with the pyrimidine bases in the presence of Lewis acids stannic chloride or trimethyl silyl triflate following Vorbruggen procedure. Proof of the structure and configuration was obtained through (1)H NMR, (13)C NMR, Mass, elemental analysis and NOE experiments. Docking and antitumor activity of these nucleoside analogues are also reported.

Design, synthesis and antibacterial activity of novel 1,3-thiazolidine pyrimidine nucleoside analogues.

The synthesis of a new class of 1,3-thiazolidine nucleoside analogues in which furanose oxygen atom was replaced with nitrogen atom and 2'-carbon atom with sulfur atom is described. N-tert-butoxycarbonyl-2-acyloxy-4-trityloxymethyl-1,3-thiazolidine was coupled with the pyrimidine bases like uracil, thymine, etc. in the presence of lewis acids stannic chloride or trimethyl silyl triflate following Vorbruggen procedure. The antibacterial activity of the novel 1,3-thiazolidine pyrimidine nucleoside analogues is highlighted. All compounds (7a-e) with free NH group in the pyrimidine moiety showed significant biological activity against all the standard strains used and in that compounds 7d and 7e showed significant activity against 14 human pathogens tested.

Synthesis of benzoyl phenyl benzoates as effective inhibitors for phospholipase A2 and hyaluronidase enzymes.

Benzoylation of (hydroxy phenyl) phenyl methanone 2a-g to benzoyl phenyl benzoates 4a-g, a benzophenone analogue, was achieved in good yield. All the newly synthesized compounds were evaluated for their phospholipase A2 [E.C. 3.1.1.4] and hyaluronidase [E.C. 3.2.1.35] enzyme inhibitory activity in snake venom as source and their structure-activity relationship with respect to different groups is reported for the first time. The in vitro PLA2 enzyme inhibitory activity and in vivo anti-inflammatory activity studies of benzoyl phenyl benzoates are illustrated.

Synthesis and antimicrobial study of novel heterocyclic compounds from hydroxybenzophenones.

The triazolothiadiazine analogues 6a-e were obtained via a multistep synthesis sequences beginning with the hydroxybenzophenones 1a-e. Hydroxybenzophenones on reaction with ethyl chloroacetate affords ethyl (2-aroylaryloxy)acetates 2a-e which on treatment with hydrazine hydrate yields 2-(2-aroylaryloxy)acetohydrazides 3a-e. Intramolecular cyclization of 3a-e with carbon disulfide affords 5-(2-aroylaryloxy)methyl-1,3,4-oxadiazole-2-(3H)thiones 4a-e, which on treatment with hydrazine hydrate yields 4-amino-5-(2-aroyl aryloxy)methyl-1,2,4-triazole-3-(2H)thiones 5a-e. Condensation of 5a-e with alpha-halocarbonyl compound results in 3-(2-aroylaryloxy)methyl-6-phenyl-1,2,4-triazolo[3,4-b][1,3,4] thiadiazine 6a-e analogues. The compounds 4a-e, 5a-e and 6a-e were tested against variety of fungal and bacterial strains in comparison to fluconazole and chloramphenicol, respectively.

Synthesis and anti-mildew activity of 5-(2-aroyl)aryloxymethyl-2-phenyl-1 ,3,4-oxadiazoles against downy mildew of pearl millet.

A manipulatively simple, rapid, high-yielding and environmentally benign method for the integration of a heterocyclic ring, 1,3,4-oxadiazole, at the benzophenone nucleus has been achieved through intramolecular cyclization of substituted aroylaryloxyacetohydrazides to substituted 5-(2-aroyl)aryloxymethyl-2-phenyl-1,3,4-oxadiazoles under solventless 'dry' conditions using montmorillonite K10 clay and microwave irradiation. A comparison is made of the microwave-accelerated reaction with conventional heating conditions. Certain of the derivatives tested showed significant anti-mildew activity against Sclerospora graminicola (Sacc) Schroeter, the downy mildew pathogen of pearl millet.

Synthesis of some newer analogues of substituted dibenzoyl phenol as potent anti-inflammatory agents.

Benzoylation of hydroxybenzophenones 1a-f affords substituted benzoyl phenyl benzoates 3a-f, which on Fries rearrangement using microwave irradiation led to a facile synthesis of solely dibenzoyl phenols 4a-f in excellent yield. The newly synthesized compounds were screened for their anti-inflammatory activity and were compared with standard drugs. Out of the compounds studied, the compound 4e showed more potent activity than the standard drugs at all doses tested.

Synthesis and anti-inflammatory activity of benzophenone analogues.

A series of substituted benzophenone analogues has been synthesized and evaluated as orally active anti-inflammatory agents with reduced side effects. The anti-inflammatory and ulcerogenic activities of the compounds were compared with naproxen, indomethacin, and phenylbutazone. In carrageenan-induced foot pad edema assay, benzophenone analogues showed an interesting anti-inflammatory activity. In the air-pouch test, some of the analogues reduced the total number of leukocytes of the exudate, which indicates inhibition of prostaglandin production. Side effects of the compounds were examined on gastric mucosa, in the liver and stomach. None of the compounds showed significant side effects compared with nonsteroidal anti-inflammatory drugs such as indomethacin and naproxen.

Synthesis of benzophenone oxime analogues as inhibitor of secretory phospholipase A(2) with anti-inflammatory activity.

The title compound have been synthesized and tested for structure activity relationship for Phospholipase A(2) (PLA(2)) [E.C. 3.1.1.4] enzyme inhibition. The in vitro PLA(2) enzyme inhibitory activity of benzophenone oxime analogue and in vivo anti-inflammatory activity studies using mice are highlighted.

Crystal structure of 2-chloro-3-(beta-nitrovinyl)quinoline.

2-Chloro-3-(beta-nitrovinyl)quinoline (CNQ) was crystallographically studied owing to its medicinal properties and its occurrance in numerous commercial products, including pharmaceuticals, fragrances and dyes. The vinyl group is planar, and takes up an extended conformation. An hydrogen bonding of C-H...N type helps to stabilize the molecules in the unit cell.