Ghulam Murtaza Maharvi

An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite

Abstract Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.

Mild and efficient synthesis of new tetraketones as lipoxygenase inhibitors and antioxidants

A mild and efficient route to tetraketones (2–22) has been developed by way of tetraethyl ammonium bromide (Et4N+Br− ) mediated condensation of dimedone (5,5-dimethylcyclohexane-1,3-dione, 1) with a variety of aldehydes. All these compounds showed significant lipoxygenase inhibitory activity and moderate to strong antioxidant potential. Compounds 19 (IC50 = 7.8 μM), 22 (IC50 = 12.5 μM), 3 (IC50 = 16.3 μM), 11 (IC50 = 17.5 μM) and 8 (IC50 = 21.3 μM) showed significant inhibitory potential against lipoxygenase (baicalein, IC50 = 22.4 μM). On the other hand compound 19 (IC50 = 33.6 μM) also showed strong antioxidant activity compared to the standard (IC50 = 44.7 μM). This study is likely to lead to the discovery of therapeutically efficient agents against very important disorders including inflammation, asthma, cancer and autoimmune diseases.

Antibacterial and Antifugal Mono- and Di-substituted Symmetrical and Unsymmetrical Triazine-derived Schiff-bases and their Transition Metal Complexes

A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/antifungal against two or more species as compared to the uncomplexed Schiff-base ligands.

Organotin(IV) Complexes of Aniline Derivatives. I. Synthesis, Spectral, and Antibacterial Studies of Di- and Triorganotin(IV) Derivatives of 4-Bromomaleanilic Acid

Organotin(IV) derivatives of the general formulae R2SnL2 and R3SnL where R = Me, n‐Bu, n‐Oct, Ph and Bz and HL = 4‐bromomaleanilic acid have been synthesised. These compounds were characterized by elemental analyses, infrared, multinuclear (1H, 13C, 119Sn) NMR and mass spectrometry. Biological screenings were performed in order to establish their biological activity.

Synthesis and inhibitory potential towards acetylcholinesterase, butyrylcholinesterase and lipoxygenase of some variably substituted chalcones

A series of variably substituted chalcones were synthesized by condensation of substituted acetophenones with mono-, di- or trisubstituded benzaldehydes. It was observed that some of these compounds have the potential to inhibit acetylcholinesterase, whereas others show activity against butyrylcholinesterase, depending on the substitution pattern at the two aromatic rings of these chalcones. Similarly, lipoxygenase was inhibited by two of these compounds. It has been observed that inhibition of the three enzymes was concentration dependent with the IC50 values ranging from 28.2–134.5 μM against acetylcholinesterase, 16.0–23.1 μM against butyrylcholinesterase and 57.6–71.7 μM against lipoxygenase, respectively.

Leishmanicidal potential of N-substituted morpholine derivatives: synthesis and structure-activity relationships.

A series of N-substituted morpholines 2–20 was synthesised by reacting various acid chlorides and alkyl halides with morpholine (1). All of the synthesised compounds 2–20 were screened for their leishmanicidal effects using amphotericin B (IC50 = 0.24 µg L−1) and pentamidine (IC50 = 2.56 µg mL−1) as standards and a structure–activity relationship (SAR) study was established. The compounds 2 (IC50 = 48 µg mL−1), 3 (IC50 = 30.0 µg mL−1), 10 (IC50 = 41.0 µg mL−1), 15 (IC50 = 33.0 µg mL−1), 16 (IC50 = 35.0 µg mL−1) and 20 (IC50 = 47.0 µg mL−1) showed weak leishmanicidal activities.

A facile and improved synthesis of sildenafil (Viagra®) analogs through solid support microwave irradiation possessing tyrosinase inhibitory potential, their conformational analysis and molecular dynamics simulation studies

Herein, the synthesis of some analogs of sildenafil (Viagra®) (21) is described, employing MW irradiations in key steps such as, SNAr reaction on important precursor bromopyrazole (7). Compound 7 was synthesized by the bromination followed by the amidation of readily available 1-methyl-3-propyl-1H-pyrazole-5-carboxylic acid (5). Compounds 9 and 10 were obtained as SNAr reaction products, apparently through the proposed dipolar high-energy transition states TS-1 and TS-2 under MW irradiation, respectively. In contrast, conventional heating failed to produce similar results, even after prolonged heating. Compound 10, upon chlorosulfonation followed by the coupling of various nucleophiles, yielded a series of compounds 12–20 as analogs of sildenafil (21). Compounds 12–21 were subjected to tyrosinase inhibition studies and SAR studies were carried out. This study reflected that the inhibition was enhanced with increase of carbon chain. In case of the compound 17, the –OH group was replaced with –CH2–CH2–OH with a resulting increase in inhibition against tyrosinase. Compound 17 was found to be more potent than the potent reference inhibitor LM and KA. The 2D and 3D hydrogen bonding descriptors that help to study QSPR were also calculated. Energetically most stable conformations of these compounds were analyzed. Their kinetic, potential and total energies were also calculated through MD simulation.

An alternative method for the synthesis of γ-lactones by using cesium fluoride-celite/acetonitrile combination

Abstract A variety of 2-(1-bromoalkyl) benzoic acids 4 undergo intramolecular nucleophilic substitution reaction when treated with a CsF-Celite as solid base in acetonitrile under reflux condition to give the corresponding cyclized phthalides in moderate to very good yield. These 2-(1-bromoalkyl) benzoic acids 4 are formed by the α-bromination of 2-alkylbenzoic acids 3 using N-bromosuccinimide and a catalytic amount of α,α′-azoisobutyronitrile in carbon tetrachloride under reflux.

An Alternative Method for the Highly Selective Iodination of Alcohols Using a CsI/BF3·Et2O System

Abstract A variety of allylic and benzylic alcohols have been converted into the corresponding iodides using cesium iodide (CsI) in the presence of boron trifluoride etherate (BF3·Et2O) in acetonitrile under mild conditions.

Piperidines: A new class of Urease inhibitors

A variety of piperidines (2–12, 14–26) with variable substituents at N-atoms have been synthesized and evaluated as urease inhibitors. The synthesized compounds showed varying degree of urease inhibitory activity ranging from 31.97 to 254 μM. The size and electron-donating or -withdrawing effects of substituents influence the activity, which lead to the formation of urease inhibitors.