Synthesis and Antimicrobial Activity of 2-(Aminoacid ester)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2 λ5- benzoxazaphosphinin-2-thiones

Synthesis of 2-(aminoacid ester)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2λ5-benzoxazaphosphinin-2-thiones (3a–j) was accomplished through a two-step process. It involves the prior preparation of 2-chloro-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2λ5-benzoxazaphosphinin-2-thione monochloride (2) and its subsequent reaction with the aminoacid ester hydrochlorides in dry tetrahydrofuran-toluene in the presence of triethylamine at various temperatures. These compounds were characterizedby IR, 1H, 13C, 31P NMR and mass spectral data.Keywords: 2-[(6-methyl-2-pyridyl) amino] methylphenol, 1,3,2-benzoxazaphosphinin-2-thione, antimicrobial activit

A meglumine catalyst–based synthesis, molecular docking, and antioxidant studies of dihydropyrano[3, 2-b]chromenedione derivatives

A simple method was employed for the synthesis of dihydropyrano[3, 2-b]chromenedione derivatives (4a-o) in high yields by condensation of 5, 5-dimethylcyclohexane-1, 3-dione(1), different aromatic aldehydes (2a-o), and 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one(3), using meglumine as a stable and reusable catalyst. Meglumine, an amino sugar, was employed as an environmentally benign catalyst, due to its splendid properties such as being inexpensive, recyclable, and biodegradable. The accomplished protocol employs low catalyst loading and easy work-up for the synthesis of 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one derivatives. A great asset is that without any significant loss, the catalyst could be recovered and reused for extended synthetic steps. This offer huge advantage to overcome recyclability issues. Our synthesized compounds were analyzed by IR, 1H, 13C NMR, mass spectra and evaluated for their antioxidant properties by 1, 1-diphenyl-2-picryl hydrazyl radical (DPPH), hydrogen peroxide(H2O2), and nitric oxide (NO) scavenging methods. The correlation in exhibition of antioxidant activity was effective at all doses. The binding interactions and molecular docking studies for entitled compounds were studied against 3MNG protein; 4k exhibited marked binding affinity with excellent docking score of −7.6 Kcal/mol and emerged as a lead compound. © 2019 Wiley Periodicals, Inc.Ural Federal University, UrFUThe authors G. Sravya and N. Bakthavatchala Reddy are thankful to Ural Federal University, Yekaterinburg, Russia, for postdoctoral fellowship

Nonlinear Thermal Analysis of Functionally Graded Plates Using Higher Order Theory

In this paper, the nonlinear thermal analysis of functionally graded material (FGM) plate with material variation parameter (n), boundary conditions, aspect ratios and side to thickness ratios is investigated using higher order displacement model. The derivation of equations of motion for higher order displacement model is obtained using principle of virtual work. The nonlinear simultaneous equations are obtained by Navier's method considering certain parameters, loads and boundary conditions. The nonlinear algebraic equations are solved using Newton Raphson iterative method. The effect of shear deformation and nonlinearity response of functionally graded material is investigated. Keywords: Nonlinear thermal analysis, FGM plates, higher order theory, Navier's method, Newton Raphson method

VALIDATED GRADIENT STABILITY INDICATING RP-HPLC METHOD FOR THE SIMULTANEOUS QUANTIFICATION OF 11 RELATED SUBSTANCES IN THE COMBINED DOSAGE FORMS OF LAMIVUDINE AND TENOFOVIR DISOPEOXIL FUMARATE

Objective: Development of a stability-indicating reverse phase liquid chromatographic (RP-HPLC) method for the simultaneous quantification of 11 impurities in the combined dosage forms of lamivudine and tenofovir disoproxil fumarate drug substances.Methods: Efficient chromatographic separation of all analytes was achieved on a Waters X-terra RP18 column (150 x 4.6 mm, 3.5 mm) using mobile phase A (ammonium acetate buffer, pH adjusted to 5.0±0.05 with dilute orthophosphoric acid) and mobile phase B (mixture of methanol and ammonium acetate buffer in the ratio of 20:80) with the flow rate of 1.0 ml/min in gradient elution mode at 260 nm.Results: The method was validated in terms of the limit of detection, limit of quantification, linearity, accuracy, precision and robustness according to the international conference on harmonisation (ICH Q2R1). Regression analysis showed that the correlation coefficient (r2) is greater than 0.997 for individual active drug substances as well as their related substances. The method has proven very accurate (94.6 % to 108.2 % with % RSD not more than 4.9), highly precise (% RSD of the Intra-day and the inter-day study was not more than 8.9) and robust enough to deliver accurate results, when the chromatographic conditions were altered intentionally. Forced degradation studies were conducted in acidic, basic, thermal, photolytic, humid and peroxide stress conditions, where all the degradation peaks were monitored. Highest degradation of lamivudine was observed under oxidative stress condition and tenofovir was more susceptible to degradation under acidic and alkaline conditions.Conclusion: The present method is able to separate all the related compounds with each other and with the main drug substances with the resolution more than 2.0. The test solution was found to be stable in diluent up to 24 h. The mass balance of forced degradation of formulations, close to 99 %, made this method as a stability indicating method

Synthesis and Antimicrobial Activity of 3-[(4-Substituted) (2-oxo-1,3-oxazolidin-3-yl) phosphoryl]- 1,3-oxazolidin-2-ones

3-[(4-Substituted) (2-oxo-1,3-oxazolidin-3-yl)-phosphoryl]-1,3-oxazolidin-2-ones (4a–j) were synthesized through a two-step process. Bis-(2-oxo-1,3-oxazolidin-3-yl)-phosphonic chloride (2) prepared by the reaction of two moles of oxazolidin-2-one (1) with phosphorus oxychloride in dry tetrahydrofuran in the presence of triethylamine and treatment with various heterocyclic aromatic and aliphatic amines under the same experimental conditions afforded the title compounds (4a–j). They were characterized by elemental analysis, IR,NMR(1H, 13Cand 31P) and mass spectroscopy. Their antimicrobial activities were also evaluated.Keywords: 3-[(4-Substituted) (2-oxo-1,3-oxazolidin-3-yl)-phosphoryl]-1,3-oxazolidin-2-ones, oxazolidin-2-one, bis-(2-oxo-1,3-oxazolidin-3-yl)-phosphonic chloride, antimicrobial activity, spectral studie

Calcium Bromide Catalysed Synthesis and Anticoagulant Activity of Bis(α-aminophosphonates)

A simple and efficient microwave irradiated synthesis of bis(α-aminophosphonates) has been developed by the reaction of 1,2-diphenylethane-1,2-diamine, aromatic aldehydes, and dimethyl phosphite in the presence of calcium bromide as catalyst under neat conditions at room temperature. All the title compounds were screened for their anticoagulant activity using blockasol as standard. The compounds containing thio group exhibited promising anticoagulant activity when compared to blockasol. © 2020 Author(s)

Green Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates

A facile and highly efficient and green synthetic protocol is developed for the bioactive 2-amino-3-cyano-4H-chromen-4-ylphosphonates by the one-pot reaction of various salicylaldehydes, malononitrile, and diethyl phosphite using sulfamic acid as an efficient, reusable and heterogeneous solid acid catalyst. All the synthesized compounds were characterized by their 1H-NMR, 13C-NMR, 31P-NMR, and Mass spectral studies. © 2020 Author(s).The authors are thankful to Prof. C. Devendranath Reddy, Department of Chemistry, S.V. University, Tirupati for his helpful discussions and acknowledge DST-PURSE 2nd Phase Programme in S.V. University, Tirupati funded by DST-New Delhi, India for providing instrumentation facility and funding to Mr. Gundluru Mohan through SRF (File No: 17118-UGC-III(3)/ DST-PURSE 2nd Phase/2017, Dt: 23-08-2018)

Ultrasound-Assisted PSA Catalyzed One-Pot Green Synthesis of Pyrazolyl Pyrrole Derivatives

A fast, efficient and environmentally benign synthesis of pyrazolyl pyrrole derivatives has been developed by the one-pot multicomponent reaction of an aldehyde, nitroalkane, amine, and enolizable reactant with active C-H group, using Phosphosulfonic acid (PSA) as reusable solid acid catalyst under mild, solvent-free, ultra-sonication conditions. In comparison to the existing conventional methods, this green and efficient protocol provides remarkable advantages such as good to excellent yields, lower reaction time, less cost, easy work-up and solvent-free. © 2020 Author(s).The authors are thankful to Prof. C. Devendranath Reddy, Department of Chemistry, S.V. University, Tirupati for his helpful discussions and acknowledge DST-PURSE 2nd Phase Programme in S.V. University, Tirupati funded by DST-New Delhi, India for providing instrumentation facility and funding to Mr. Gundluru Mohan through SRF (File No: 17118-UGC-III (3)/ DST-PURSE 2nd Phase/2017, Dt: 23-08-2018)