Abha Bishnoi

Expedient synthesis of some novel pregnane derivatives and their evaluation as anti-oxidant and anti-dyslipidemic agents

Synthesis of a number of novel pregnane derivatives has been described in detail. They were prepared by reaction of 3β-hydroxy-5, 16-pregnadiene-20-one (2) with diethylene glycol, 2-methoxy ethanol, 1,2-propane diol, p-chloroaniline and p-fluoroaniline, respectively. The structures of these newly synthesized compounds have been established on basis of physical, analytical and spectral data. These pregnane derivatives have been evaluated for their anti-dyslipidemic activity (Triton model) and in vitro antioxidant activities. Out of the 12 compounds tested, 3 of them showed potent anti-dyslipidemic activity and 7 showed potent antioxidant and scavenger of oxygen free radicals.

Synthesis, characterization and biological activity of new cyclization products of 3-(4-substituted benzylidene)-2H-pyrido[1,2-a]pyrimidine 2,4-(3H)-diones

AbstractA method is presented for the synthesis of 4-(substituted phenyl)-3-(3-substituted phenyl)4H-spiro[isoxazole-5,3′-pyrido[1,2-a]pyrimidine]-2′,4′-dione (3), 3-(4-substituted phenyl)-3H-isoxazole[3, 4-d]pyrido[1,2-a]pyrimidin-4-(3aH)-one (4) and 3-(4-substituted phenyl) 3,3a-dihydropyrazolo[3,4-d]pyrido[1,2-a]pyrimidin-4-(2H)-one (5) which consists of the conversion of 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-dione (1) to chalcones (2) and their 1,3-dipolar cycloaddition with appropriate aldoximes to give spiro compounds and heterocyclization using amines to yield isoxazolines and pyrazolines. All the compounds were screened for their antimicrobial and antitubercular activity. Graphical Abstract1,3-Dipolar cycloaddition of pyrido-pyrimidine chalcones with appropriate aldoximes give spiro compounds; heterocyclization using hydroxylamine or hydrazine to yield isoxazolines or pyrazolines, respectively. All the compounds were then screened for their biological (antimicrobial and antitubercular) activity.

Spectroscopic (FT-IR, FT-Raman, and UV-visible) and quantum chemical studies on molecular geometry, Frontier molecular orbitals, NBO, NLO and thermodynamic properties of 1-acetylindole.

Quantum chemical calculations of ground state energy, geometrical structure and vibrational wavenumbers of 1-acetylindole were carried out using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. The FT-IR and FT-Raman spectra were recorded in the condensed state. The fundamental vibrational wavenumbers were calculated and a good correlation between experimental and scaled calculated wavenumbers has been accomplished. Electric dipole moment, polarizability and first static hyperpolarizability values of 1-acetylindole have been calculated at the same level of theory and basis set. The results show that the 1-acetylindole molecule possesses nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. UV-Visible spectrum of the molecule was recorded in the region 200-500nm and the electronic properties like HOMO and LUMO energies and composition were obtained using TD-DFT method. The calculated energies and oscillator strengths are in good correspondence with the experimental data. The thermodynamic properties of the compound under investigation were calculated at different temperatures.

Synthesis, characterization, and biological evaluation of novel thiazole and pyrazole derivatives of quinoline-4-carboxylic acid as potential antimicrobial agents

A series of quinoline-based heterocycles prepared and bioevaluated for their possible antimicrobial activity against a panel of gram-positive bacteria [Staphylococcus aureus (ATCC-9144) and Bacillus subtilis (ATCC-6633)] and gram-negative bacteria [Pseudomonas aeruginosa (ATCC-25615), and Escherichia coli (MTCC-739)], and fungal strains [Candida albicans (ATCC-24433), Aspergillus niger (MTCC-872), and Aspergillus fumigatus (MTCC-343)] by the known methods. All the prepared quinoline derivatives have shown significant antimicrobial activities. Few compounds, viz. 4b, 4c and 4a, 4c proved to be active at low concentrations against Sa and Ca, respectively, while compounds 4a, 6d, and 6b showed milder inhibitory effects against other microbes. The structures of newly synthesized compounds were characterized by elemental analysis, Infrared (IR), 1HNMR, 13C-NMR and Mass-spectroscopy.

Design, synthesis and antimicrobial properties of novel 3,3a,4,5,6,7- hexahydroindazole and arylthiazolylpyrazoline derivatives.

A remarkable diastereoselective synthesis of some novel arylthiazolyl pyrazoline derivatives 3(a-l) is displayed which were evaluated for their in vitro antimicrobial activities. In particular, compounds 3e, 3g & 3l (MIC 12.5 μg /ml) showed good activity against S. aureus and compounds 3b & 3j (MIC 12.5 μg / ml) against B. subtilis. Compounds 3g, 3i, 3j (MIC 12.5 μg/ ml) and 3l (MIC 6.25 μg / ml) also displayed excellent antifungal activity against C. albicans. Of all the synthesized compounds, 3g and 3e exerted a wide range of antibacterial activities against entire tested gram positive (S. aureus and B. subtilis) and gram negative (E. coli and P. aeruginosa) bacterial strain except P. aeruginosa.

Synthesis and Biological Evaluation of Novel 5-Oxo-1-Phenylpyrrolidine-3-Carboxylic Acid Analogs

A number of 5-oxo-1-phenyl-4-(substituted methyl) pyrrolidine-3-carboxylic acid derivatives bearing pyrrolidine ring and methylamino residues in their structure were synthesized as potential antibacterial drugs. The chemical structures of all the compounds were established by their UV-Vis absorption spectroscopy, IR, 1H, 13C NMR and mass spectroscopy. The in vitro antibacterial screening of all novel compounds was done against gram-positive Staphylococcus aureus, Bacillus subtilis and gram-negative Pseudomonas aeruginosa. The results revealed that compounds 5d, e, f and g showed moderate to good activity against the tested microbes.

Discovery of Novel Thiazol-2-Amines and Their Analogues as Bioactive Molecules: Design, Synthesis, Docking and Biological Evaluation

A simple and highly efficient procedure for the synthesis of novel thiazol-2-amines, via Mannich reaction with secondary amines, is described. The newly synthesized derivatives 8(A-E): and 9(A-E): were characterized by 1H NMR, 13C NMR, IR, Mass spectroscopy and elemental analysis. All the derivatives were evaluated for their in-vitro anti-microbial activity against a panel of pathogenic strains of bacteria and fungi. The SAR showed that the secondary amines had a significant impact on the in-vitro antimicrobial activity of this class of agents. The most potent analogue N-((1H-benzo[d]imidazol-1-yl)methyl)-N-(2(trifluoromethyl)phenyl)-4,5-dihydrothiazol-2-amine (8C): showed excellent inhibition with MIC (zoi) 6.25 (22.5), 25 (21.5) and 25 (18) µg/mL against E. coli, S. typhi and P. aeruginosa respectively as compared to the standard drug. Molecular docking results suggest that compound exhibited inhibitory activity by binding of the title compound within the active sites of the inhibiting Enoyl ACP reductase, Lipid A, Pyridoxal kinase and type I DHQase enzymes. The compound exhibited promising anti-microbial activity which can be further explored as potential lead for the development of cheaper, safe, effective and potent drugs against resistant microbial parasites.

Synthesis, characterization, and antimicrobial evaluation of novel spiropiperidones

Abstract Novel spiro derivatives of piperidone 4a–f were synthesized, characterized, and screened against a panel of different bacterial and fungal strains. The study revealed the potential of these molecules for further development as antimicrobial agents.