S. Shashikanth

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.

Antiangiogenic effect of 2-benzoyl–phenoxy acetamide in EAT cell is mediated by HIF-1α and down regulation of VEGF of in-vivo

Benzophenones and its analogues are known for wide range of biological properties. Synthetic benzophenone analogue 2-benzoyl -phenoxy acetamide (BP-1) is proven to be potent antitumor and proapoptotic activity against EAT cells in-vivo. In the present report, we studied the antiangiogenic effect of BP-1 in EAT cells induced angiogenesis. Treatment with BP-1 in-vivo was demonstrated by the down regulation of the secretion of VEGF from EAT cells and inhibition of blood vessels formation indicating the potential angioinhibitory effect of BP-1 in EAT cells. HIF-1α protein, a transcription factor known to be key a regulator in hypoxia-induced angiogenesis was also down regulated by BP-1. Our findings indicated that, HIF-1α nuclear sequestration is repressed by BP-1 through inhibition of nuclear translocation. We postulate that diminished HIF-1α nuclear presence and activity in BP-1 treated EAT cells could be responsible for decreased VEGF expression and antiangiogenic effects.

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.

ZrO2-supported Cu(II)–β-cyclodextrin complex: construction of 2,4,5-trisubstituted-1,2,3-triazoles via azide–chalcone oxidative cycloaddition and post-triazole alkylation

An efficient one-pot three-component stepwise approach for the synthesis of N-2-substituted-1,2,3-triazoles from chalcones, sodium azide and esters has been developed using a recoverable and reusable ZrO2 nanoparticle-supported Cu(II)–β-cyclodextrin complex as a catalyst. N-2 alkylation of triazoles using different aryl–alkyl esters without any additives has been achieved for the first time. The one-pot operation, atom-economical nature, regioselectivity and good yields are the noteworthy features of this protocol. The reusability of the prepared nanocatalyst was successfully examined four times without any appreciable loss in catalytic activity.

ZrO2-β-cyclodextrin catalyzed synthesis of 2,4,5-trisubstituted imidazoles and 1,2-disubstituted benzimidazoles under solvent free conditions and evaluation of their antibacterial study

A series of 2,4,5-trisubstituted imidazoles and 1,2-disubstituted benzimidazoles catalyzed by ZrO2-supported-β-cyclodextrin (ZrO2-β-CD) under solvent free conditions have been synthesized and characterized by spectral methods. The nanoparticles (ZrO2-β-CD), prepared by a simple one-pot-coprecipitation method and were characterized by PXRD, SEM, and TEM techniques. The nano (ZrO2-β-CD) particles were found to be an effective heterogeneous reusable catalyst for the effective synthesis of imidazoles and benzimidazoles under solvent free conditions and all of the synthesized derivatives were evaluated for their antibacterial activity against six bacterial strains.

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.

(4-Methoxy­phen­yl)(2-methyl­phen­yl)methanone

In the title compound, C15H14O2, the dihedral angle between the two benzene rings is 56.34 (7)°.

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 antimicrobial activity of novel (3,5- dichloro-4-((5-aryl-1,3,4-thiadiazol-2-yl)methoxy) phenyl) aryl methanones

A series of novel (3,5-dichloro-4-((5-aryl-1,3,4-thiadiazol-2-yl)methoxy)phenyl) aryl methanones (10a-f), were synthesized by condensing 2-chloromethyl-5-aryl-1,3,4-thiadiazole (9a-c) with aryl(3,5-dichloro-4-hydroxyphenyl) methanones (4a-b) using TBAB and K2CO3. The chemical structure of the newly synthesised compounds was characterized by analytical and spectral (IR, 1 H NMR, and LC-MS) methods. The title compounds were screened for qualitative (zone of inhibition) and quantitative antimicrobial activity (MIC) by agar well and microbroth dilution technique, respectively. Among the synthesized compounds in the series, the compound 10f was found to exhibit significant antibacterial activity at lower concentration, against Gram positive bacteria such as Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus and Gram negative bacteria such as E.coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae. The rest of the analogues in the series displayed moderate antimicrobial activity when compared to the standard positive controls gentamicin and nystatin.

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 H2S/NH4OH 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.