K. Ajay Kumar

A NOVEL SYNTHESIS OF ISOXAZOLES VIA 1,3-DIPOLAR CYCLOADDITION OF NITRILE OXIDES TO ACETYL ACETONE

ABSTRACT Nitrile oxides (2) isolated from the oxidative dehydrogenation of aldoximes (1) by chloramines-T react with acetyl acetone (3) to afford 4-acetyl-3-aryl-5-methyl isoxazoles (5) in good yield. All new compounds were characterized by IR, 1H NMR, 13C NMR, MS studies and elemental analysis.

Synthesis and evaluation of antifungal and antibacterial activity of ethyl 3,5-diarylisoxazole-4-carboxylates

Nitrile oxides generated in situ by the oxidative dehydrogenation of aldoximes (2) react with α-cyanocinnamate esters (1) to afford ethyl 3,5-diarylisoxazole-4-carboxylates (4) in good yield. The esters (4) were tested for their antimicrobial activity.

A new approach for the transformation of alkenes to pyrrolines via aziridine intermediates

Abstract Alkenes (1) reacts with chloramine-T in presence of the catalyst silver nitrate to afford aziridines (2). The aziridines underwent ring expansion with the acrylo nitrile or ethyl acrylate (3) in the presence of solid sodium hydroxide to form pyrrolines (4) in 40–58% yield.

Synthesis of coumarin appended pyrazolyl-1,3,4-oxadiazoles and pyrazolyl-1,3,4-thiadiazoles: Evaluation of their in vitro antimicrobial and antioxidant activities and molecular docking studies

A series of semicarbazones, thiocarbazones, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles bearing coumarin and pyrazole moiety have been synthesized. The new synthesized compounds were screened in vitro for their antimicrobial and antioxidant activities. Preliminary studies showed that among the synthesized new compounds, chloro-substituted thiosemicarbazone showed excellent activities against all tested organisms; at the same time, methyl substituted thiosemicarbazone showed greater activity against E. coli. Chloro-substituted 1,3,4-oxadiazole and 1,3,4-thiadiazole demonstrated greater DPPH and hydroxyl radical scavenging abilities. Molecular docking studies indicate that 1,3,4-oxadiazoles and 1,3,4-thiadiazoles manifest better interaction with CAT (catalase) and GPx (glutathione peroxidase) than that with SOD (superoxide dismutase). Studies on the antimicrobial and antioxidant activities of the synthesized compounds compared with those of their starting compounds are discussed.

3-Methyl-1,5-diphenyl-4,5-dihydro-1H-pyrazole

In the title compound, C16H16N2, the dihydropyrazole ring adopts a shallow envelope conformation, with the C atom bearing the phenyl group displaced by 0.298 (2) Å from the other atoms (r.m.s. deviation = 0.015 Å). The dihedral angles between the four near coplanar atoms of the central ring and the N- and C-bonded phenyl groups are 13.49 (13) and 82.22 (16)°, respectively.

Evaluation of new tetra substituted pyrazolines for their antimicrobial and antioxidant activity; Structure-activity relationship

A series of synthesized new 8-(5-aryl-4-octyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-yl)-octanoic acid ethyl esters 1 were evaluated in vitro for their antibacterial and antifungal activity against different organisms. The compounds were tested for their antioxidant activity and their reducing power ability. The structure-activity relationship of the compounds was described. I. Introduction The five membered heterocycles pyrazoles and their derivatives have flourished with considerable intensity because of their synthetic and biological applications. The literature review shows that pyrazoles have known to exhibit enormous biological activity such as antibacterial, antifungal, anti-inflammatory, anticonvulsant, hypoglycemic and anticancer activities. The pyrazoles possess antipyretic, antitumour, tranquilizing and herbicidal activities. Pyrazole derivatives are reported to exhibit antioxidant (1) and antimicrobial (2-4). A series of 3-substituted-5-hydroxy-5-trifluoro(chloro)methyl-1H-isonicotinoyl-4,5- dihydropyrazoles were synthesized and their in vitro antimicrobial activity was tested against INH susceptible mycobacterium tuberculosis H37Rv (5). Human body requires tats to function properly. Fatty acids serve as the components of more complex membrane lipids and as major components of stored fat in the body. Chemically, fatty acids and their esters are used in the synthesis of much class of compounds. 4,4-Dimethyl-2-oxazolines of fatty acids are useful derivatives for mass spectrometric analysis. The utility of these adducts for structural investigations of natural and artificial fatty acids is now well established (6). Recently Rai et al (7) reported the synthesis of 5-methyl-2- (5-methyl-1,3-diphenyl-1H-pyrazole-4-carbonyl)2,4-dihydro-pyrazol-3-ones and their antimicrobial and antioxidant activity. They also demonstrated the synthesis and antimicrobial activity of bis-heterocycles bearing pyrazoline and imidazole moieties (8). Pyrazolines obtained by the reaction of 4-acetyl thioanisole with aryl aldehydes through α,β-unsaturated ketones found to exhibit analgesic and anti-inflammatory activities (9). In view of the varied biological potency associated with pyrazole and their derivatives, a series of synthesized new tetra substituted pyrazolines (10) were considered for studying their biological activities. II. Materials And Methods The chemicals/reagents used were purchased from sigma-aldrich chemicals (India) and Merck Chemicals (India). In view of the biological potency associated with pyrazole derivatives, in the present investigation; the synthesized new 8-(5-aryl-4-octyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-yl)-octanoic acid ethyl esters 1 (10) were considered for studying their antifungal, antibacterial, antioxidant activities and their reducing power ability.

4-(Thio-phen-2-yl)-2-[4-(tri-fluoro-meth-yl)phen-yl]-2,3-di-hydro-1,5-benzo-thia-zepine.

In the title compound, C20H14F3NS2, the seven-membered thiazepine ring adopts a slightly distorted twist–boat conformation. The mean plane of the five-membered thiophene ring fused to the thiazepine ring is twisted by 32.3 (3) and 55.6 (4)° from the benzene and phenyl rings, respectively. In the crystal, inversion dimers linked by pairs of weak C—H⋯N interactions are observed.

Synthesis of 8-(5-Aryl-4-Octyl-2-Phenyl-3, 4-Dihydro-2H-Pyrazol- 3-yl)-Octanoic acid ethyl esters via 1, 3-Dipolar Cycloaddition Reaction

Aldehyde phenyl hydrazones 2a-i undergo oxidative dehydrogenation with Chloramine-T to give nitrile imines, which are trapped in situ by ethyl oleate 1 to afford 8-(5-Aryl-4-octyl-2-phenyl-3,4-dihydro-2H- pyrazol-3-yl)-octanoic acid ethyl esters 3a-i in good yield. The structures of the cycloadducts were confirmed by spectral studies and elemental analysis.

2-(4-Fluoro­phen­yl)-4-(thio­phen-2-yl)-2,3-di­hydro-1,5-benzothia­zepine

In the title compound, C19H14FNS2, the seven-membered thiazepine ring adopts a slightly distorted twist boat conformation. The dihedral angle between the benzene rings is 53.6 (1)°. The mean plane of the thiazepine ring is twisted by 34.3 (7)° and 36.6 (7)° from the benezene rings. A C—H⋯F interaction generates stacking of molecules along the ab plane.

Synthesis of New 3, 5-Diaryl-4, 5-Dihydroisoxazole-4- Carbonitriles via 1, 3-Dipolar Cycloaddition Reaction

Abstract : Aromatic aldoximes 1a-i undergo oxidative dehydrogenation with CrO 2 to give nitrile oxides, which are trapped in situ by 4-methoxycinnamonitrile 2 to afford of ethyl 3,5-diaryl-4,5-dihydroisoxazole-4-carbonitriles 3a-i in good yield . Key words : Isoxazoles, isoxazolines, magtreive TM , antimicrobial, antioxidant. I. Introduction Isoxazoles and isoxazolines are very useful heterocycles in organic and heterocyclic chemistry [1]. Isoxazolines also serves as important building blocks for the synthesis of various biologically active molecules [2]. The isoxazoles are known to exhibit significant number of biological applications such as hypoglycemic, analgesic, anti-inflammatory and HIV-inhibitory activity [3], also found to exhibit antibacterial [4], antifungal [5], antioxidant [6], potent selective agonists at human cloned dopamine D4 receptors [7], COX-2 inhibitory [8], antinociceptive [9], anticancer [10], and antibiotic, antitumour, insecticidal activities [1,2]. They serve as prodrug for the anti-arithretic agent [11]. Vijay V. Dabholkar and co-workers [12] reported the synthesis and their antimicrobial activity of fused isoxazolines. Joshi and et al [13] reported that isoxazoles acts as potential antitubercular agents. The most convenient synthesis of isoxazoline and isoxazole ring system has been executed in the literature via 1, 3-dipolar cycloaddition reactions of alkenes and alkynes with nitrile oxides generated