Browsing by Author "P, Amutha"

Now showing 1 - 13 of 13

ANTIOXIDANT (IN VITRO), ANTIDIABETIC (IN VITRO) AND PHOTOCATALYTIC ACTIVITY OF COSTUS SPECIOSUS LEAF EXTRACT ASSISTED CS-AG-TIO2 COMPOSITES
(Springer, 2019-10-24) C, Surya; N A A, John; V, Pandiyan; P, Amutha; A J F N, Sobral; B, Krishnakumar
The researchers have currently targeted bio-synthesis nanoparticles (NPs) and their potential applications toward bio and photocatalytic field. The in vitro antidiabetic activity of noble metal modified TiO2 is really scare in literature. In the present work, green synthesis of CS-Ag nanoparticles was achieved through Costus speciosus (Crape ginger, an Indian ornamental plant, has long been medicinally used in traditional systems of medicine) leaf extract, and followed by solvothermal synthesis of CS-Ag-TiO2 composites. The prepared nanocomposites effectively utilized for in vitro antioxidant, in vitro antidiabetic study and azo dye AB 1 degradation under visible light.
BICL3-MODIFIED PERLITE AS AN EFFECTIVE CATALYST FOR SELECTIVE ORGANIC TRANSFORMATIONS: A GREEN PROTOCOL
(Springer, 2019-05-05) K, Brindha; P, Amutha; B, Krishnakumar; A J F N, Sobral
A new perlite supported Bismuth Chloride (BiCl3) was used as an efcient heterogeneous catalyst for the synthesis of heterocyclic compounds viz., quinoxalines and dihydropyrimidinones. Fourier-transform infrared spectroscopy (FT–IR), scanning electron microscopy, energy dispersive spectra, X-ray difractometry, thermogravimetric analysis and Brunauer–Emmett–Teller surface area analytical techniques were employed to characterize the prepared catalyst. Initially, the catalytic activity of the prepared BiCl3-Perlite was tested towards synthesis of simple quinoxaline derivatives at room temperature. The efect of solvent in the preparation of quinoxaline was also examined. The formed products were confrmed by their physical (melting point) and spectral data (FT–IR, 1 H and 13C-NMR). In order to implement the activity of the BiCl3-Perlite catalyst, a multicomponent reaction was adopted for synthesis of dihydropyrimidinones under solvent free conditions in a micro oven. The use of recyclable heterogeneous solid acid catalyst makes the reaction simple with minimum chemical waste, shorter reaction time, easy workup and products in good yield.
COSTUS SPECIOSUS LEAF EXTRACT ASSISTED CS-PT-TIO2 COMPOSITES: SYNTHESIS, CHARACTERIZATION AND THEIR BIO AND PHOTOCATALYTIC APPLICATIONS
(Elsevier, 2019-11-05) C, Surya; N A A, John; V, Pandiyan; S, Ravikumar; P, Amutha; A J F N, Sobral
The antioxidative and antidiabetic properties of Costus speciosus leaf extract assisted nanoparticles (CS–Pt modified TiO2) were compared with pristine TiO2 NPs along with standard ascorbic acid (AA). CS-Pt nanoparticles were synthesized through bioreduction process and supported on titanium dioxide semiconductor. Costus speciosus (CS) leaf extract was used as reducing and capping agent. Initially, CS-Pt nanoparticles synthesis was carried out with ethanolic extract of CS, later, two different wt% of CS-Pt supported TiO2 were prepared through sol-gel cum solvothermal process. The prepared materials have been characterized using different characterization techniques such as XRD, FT-IR, Raman, SEM, HR-TEM, EDS, DRS, PL and XPS measurements. CS-Pt-TiO2 nanocomposites showed well dispersion of Pt nanoparticles on TiO2 surface. The prepared materials have been effectively utilized for in-vitro antioxidant and in vitro antidiabetic activity. Moreover, the photocatlytic activity of the materials has been tested toward NBB degradation under visible light. CS-Pt NPs modified TiO2 composites show better activity when compared with pristine TiO2 in all cases.
FACILE SYNTHESIS OF 2-AMINO-5,6,7,8-TETRAHYDRO-5,7-DIARYLPYRIDO[4,3-D]PYRIMIDIN-4-OLS
(Taylor & Francis, 2009-08-12) P, Amutha; S, Nagarajan
2-Amino-5,6,7,8-tetrahydro-5,7-diarylpyrido[4,3-d]pyrimidin-4-ols were synthesized from various ethyl 2,6-diaryl-4-oxopiperidin-3-carboxylates with guanidine hydrochloride in presence of sodium ethoxide.
INCLUSION COMPLEXES OF 3,4-DIHYDROPYRIMIDIN-2-(1H)-ONES WITH Β-CYCLODEXTRIN
(Bulgarian Chemical Communications, 2008) K, Selvambigai; P, Amutha
Qualitative aspects of the inclusion complexes of dihydropyrimidin-2-ones with β-cyclodextrin were studied in solidstate by Infrared Spectroscopy (IRS), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy(SEM). The complexes were also investigated in solution by nuclear magnetic resonance spectroscopy (1H-NMR and13C-NMR). Qualitative modifications in the number of peaks (or bands) obtained and their shifts after complexation inthe spectral methods as well as thermal analysis indicated the inclusion, show that the method of synthesis is suitablefor obtaining inclusion complexes.
SYNTHESIS AND ANTIBACTERIAL ACTIVITIES OF SOME 2-AMINO-4-(1, 1′-BIPHENYL-4-YL)-6-ARYL-6H-1, 3-THIAZINES
(Journal of Sulfur Chemistry, 2007-02-01) N, Ingarsal; P, Amutha; S, Nagarajan
A series of new 2-amino-4-(1,1′-biphenyl-4-yl)-6-aryl-6H-1,3-thiazines has been synthesized, characterized by IR, 1H NMR, 13C NMR, mass and elemental analyses and evaluated for in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria. The antibacterial data revealed that the compounds had better activity against tested organisms than the reference norfloxacin.
SYNTHESIS AND ANTIBACTERIAL ACTIVITIES OF SOME 2-AMINO-4-(1,1'-BIPHENYL-4-YL)-6-ARYL-6H-1,3-THIAZINES
(Taylor & Francis, 2007-02-01) N, Ingarsal; P, Amutha; S, Nagarajan
A series of new 2-amino-4-(1,1′-biphenyl-4-yl)-6-aryl-6H-1,3-thiazines has been synthesized, characterized by IR, 1H NMR, 13C NMR, mass and elemental analyses and evaluated for in-vitro antibacterial activity against some Gram-positive and Gram-negative bacteria. The antibacterial data revealed that the compounds had better activity against tested organisms than the reference norfloxacin.
SYNTHESIS AND ANTIMICROBIAL ACTIVITIES OF NEW 4,6‐DIARYL‐ 4,5‐DIHYDRO‐3‐HYDROXY‐2H‐INDAZOLES
(Wiley, 2011-12-19) P, Amutha; S, Nagarajan
A series of new 4,6-diaryl-4,5-dihydro-3-hydroxy-2H-indazoles 5a–5k were synthesized by the cyclization of ethyl 2-oxo-4,6-diarylcyclohex-3-ene carboxylates 4a–4k. The compounds were characterized by IR, 1 H NMR, 13C NMR, 2D NMR, and elemental analysis. The synthesized compounds were evaluated for in vitro antibacterial and antifungal activities against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger, Aspergillus flavus, and Rhizopus sp. Most of the compounds exhibited good activity against the tested organisms.
SYNTHESIS AND STEREODYNAMICS OF N-FORMYL-1,2,3- SELENADIAZOLOPYRIDINES
(Taylor & Francis, 2012-01-31) M, Ingarsal; P, Amutha; M, Gopalakrishnan; S, Nagarajan
The 4,6-diaryl-6,7-dihydro-[1,2,3]selenadiazolo[5,4-c]pyridine-5(4H)-carbalde hydes were synthesized from 2,6-diarylpiperidin-4-ones and characterized using infrared, 1H, 13C Nuclear Magnetic Resonance (NMR), and mass spectroscopic techniques. On the NMR time scale, the compounds exist in syn and anti isomeric forms. Separate signals were obtained for isomers in the NMR spectra. The compounds’ stereodynamic nature was studied based on the intensity and position of NMR signals
SYNTHESIS OF NOVEL SPIROPYRIMIDINONES
(Wiley, 2010-03-11) P, Amutha; S, Nagarajan
An efficient one-pot synthesis of new spirocyclic 2-aminopyrimidinones via the three-component reaction of a cyclic ketone, alkyl cyanoacetate, and guanidinium carbonate was developed via a domino reaction
SYNTHESIS, IN VITRO ANTIBACTERIAL AND ANTIFUNGAL EVALUATIONS OF 2-AMINO-4-(1-NAPHTHYL)-6-ARYLPYRIMIDINES
(Elsevier, 2007-04) N, Ingarsal; G, Saravanan; P, Amutha; S, Nagarajan
A series of 2-amino-4-(1-naphthyl)-6-arylpyrimidines have been synthesized and characterized by IR, NMR, MS, elemental analyses and evaluated for in vitro antibacterial and antifungal activities. Some of the compounds were found to be active against a limited panel of bacteria and fungi. In particular, compounds 4b and 4e were found to be the most effective analogs against the tested bacterial and fungal strains
THERMO-PHYSICAL, TRIBOLOGICAL AND MACHINING CHARACTERISTICS OF HASTELLOY C276 UNDER SUSTAINABLE COOLING/LUBRICATION CONDITIONS
(Elsevier, 2022-08) Nimel, Sworna Ross; N, Srinivasan; P, Amutha; Munish, Kumar Gupta; Mehmet, Erdi Korkmaz
Chemical reactivity and poor heat conductivity make nickel (Ni) and its alloys difficult to process. The aerospace industry's expectations for high-quality surfaces are one of the biggest hurdles in machining nickel components. Recent studies have found some flaws in mist lubrication techniques when utilised under high-speed cutting circumstances, thus nanoparticles with higher thermal conductivity than the base fluid is now being used in minimum quantity lubrication (MQL) systems. Nanocarbon dots (CDs) blended with bio lubricant is an effective coolant to enhance the heat transfer capability by decreasing friction. The inclusion of the right nanoparticle ratio to the base liquid is one of the most important challenges that arise when machining. This research focuses on a deeper exploration of Hastelloy C276's tribological behaviour and machinability under various cutting approaches (Dry, MQL Cryo CO2 and N-MQL). Milling trials were carried out with various speed-feed pairings and cutting conditions. Outcomes show that 0.8 wt% CDs with soybean oil reduces the surface roughness by 56–69 %, 15–24 %, and 15–26 % over dry, MQl and cryo CO2 environments. According to elemental study of cutting inserts, adhesion is the primary wear mechanism in all cutting mediums. Finally, the chillness produced by cryo CO2 has a positive effect compared to the N-MQL strategy by producing fine grains.
TRIBOENGINEERED INDUSTRIAL LUBRICANT USING PERLITE LOADED FE2O3 NANO-ADDITIVES: A GREENER APPROACH
(Tierärztliche Praxis, 2020) B, Sathishkumar; P, Tamilarasu; P, Amutha; N, Srinivasan
Nanoscale additives has received significant importance as anti-wear additives by minimizing the wear and material surface destruction of machines induced by friction between the moving parts. The friction and wear are the two essential factors that are inevitable during the manufacturing process. In this work, an attempt is made to enhance the tribological properties of industrial oil by blending the nanoparticles of Fe2O3 with pearlite. The study is carried out with two different compositions of nanoparticles in aluminum and steel using pin-on-disc wear tester. The experimental outcomes demonstrate the existence of nanoparticles enhances the wear resistance in the base lubricant.