P. Mayavel

Fly-ash:H2SO4 catalyzed solvent free efficient synthesis of some aryl chalcones under microwave irradiation

Some 2E aryl chalcones have been synthesized using greener catalyst Fly-ash:H(2)SO(4) assisted solvent free environmentally benign Crossed-Aldol reaction. The yields of chalcones are more than 90%. The synthesized chalcones are characterized by their physical constants and spectral data.

Solvent-free synthesis, spectral correlations and antimicrobial activities of some aryl imines.

A series of aryl imines have been synthesized by Fly-ash: H2SO4 catalyzed microwave assisted process under solvent-free conditions. The yields of the imines have been found to be more than 87%. The purity of all imines has been checked using their physical constants and spectral data as published earlier in literature. The UV λmaxCN(nm), infrared νCN(cm(-1)), NMR δ(ppm) of CH and CN spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The antimicrobial activities of All synthesised imines have been studied using Bauer-Kirby method.

Eco-friendly synthesis and antimicrobial activities of some 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines

Background Green catalyst fly ash: H2SO4 was prepared by mixing fly ash and sulphuric acid. Microwave irradiations are applied for solid phase cyclization of 5-bromo-2-thienyl chalcones and phenyl hydrazine hydrate in the presence of fly ash: H2SO4 yields, 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines. These pyrazolines were characterized by their physical constants and spectral data. The antimicrobial activities of all synthesized pyrazolines have been studied. Results Scanning electron microscopy (SEM) analysis shows the morphology changes between fly ash and the catalyst fly ash: H2SO4. The SEM photographs with the scale of 1 and 50 μm show the fly-ash particle is corroded by H2SO4 (indicated by arrow mark), and this may be due to dissolution of fly ash by H2SO4. The yields of 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines is more than 75% using this catalyst under microwave heating. All pyrazolines showed moderate activities against antimicrobial strains. Conclusion We have developed an efficient catalytic method for synthesis of 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines by solid phase cyclization using a solvent-free environmentally greener catalyst fly ash: H2SO4 under microwave irradiation between aryl chalcones and hydrazine hydrate. This reaction protocol offers a simple, economical, environment friendly, non-hazardous, easier work-up procedure, and good yields. All synthesized pyrazoline derivatives showed moderate antimicrobial activities against bacterial and fungal strains.

Perchloric acid catalyzed condensation of amine and aldehydes: Synthesis and antibacterial activities of some aryl (E)-imines

Abstract A series of Schiff’s bases (aryl E-imines) have been derived from the perchloric acid catalyzed condensation of aryl amines and substituted benzaldehydes. The yield of the Schiff’s bases are more than 80%. The synthesized Schiff’s bases are characterized by their physical constants, analytical and spectroscopical data. The antibacterial activities of these Schiff’s bases have been studied using Bauer-Kirby method.

SOLID FLY-ASH:H2SO4 CATALYZED MICROWAVE ASSISTED SOLVENT-FREE CONDENSATION:SYNTHESIS OF SOME TRIFLUOROMETHYL-IMINES

ABSTRACT Good yield of trifluoromethyl-imines have been synthesized by Fly-ash:H 2 SO 4 catalyzed condensation of anilines and phenyl trifluoromethyl ketone in mi-crowave irradiation under solvent free conditions. Keywords: Fly-ash:H 2 SO 4, Greener synthesis, Trifluoromethylimines, Anilines. e-mail: drgtnarayanan@gmail.com INTRODUCTION Chiral imine derivatives possess multipronged biological activities such as antimicrobial 1 , anticancer 2 , antiplasmodic-antihypoxic 3 , antitubularcular 4 , nematicidal, insecticidal1e 5 , anti-inflammatory, and lipoxygenase 6 . The imine moieties are important intermediate and versatile starting materials for synthe-sis of chiral amines 7-13 pyrimidine derivatives, phenylhydrazones, azomethines, indoles, quinoxalines, imidazoles, by hydrogenation 14 , nucleophilic addition with organometallics 15 and cycloaddition reaction 16 . The unique condensation of carbonyl compounds with amines is a well-known reaction. Many reagents 17 was obtained on evaporation of solvent. The solid, on recrystallization with were used for synthesis of optically active imines such as Lewis acids, mo-lecular sieves in ionic liquids, infrared