Organic Chemistry

4-oxo-thiazolidine have been synthesized by cyclisation of acyclic compounds and thioglycolic acid on Schiff ’s bases. All the products have been evaluated for their in vitro antimicrobial activity against various strains of bacteria.

Gulf heavy crude oil samples were separated into four fractions of saturates, mono-, di- and polyaromatics by elution open column chromatography. Alumina and a mixture of equal amount of silica and alumina stationary phases were separately used to study the effect of these stationary phases on the separation. The Gas Chromatography – Mass Spectrometry (GC – MS) results of the fractions show that the nature of the stationary phase may affect the elution of both aromatic and the saturate components of the oil. The pristane/phytane ratio ranging from 0.63-2.00 obtained for the crude oil fractions using the two stationary phases indicates an oxygen depositional environment for the source rocks.

4- Oxo- thiazolidines substituted in 2 and 3 positions exhibit a wide range of biological activities. A series of 4-oxo-thiazolidine (4 a-o) have been obtained by cyclisation of various Schiff’s base (3) with thiomalic acid. The Schiff’s bases (3) are obtained by the reaction of 4 – Methyl cinnamoyl hydrazine with appropriate benzaldehyde. The product is characterized by spectral and analytical data. Most of the tested compounds show promising antibacterial activity.

Conductive polymers are good candidates for preparation of conducting graft copolymers. Therefore, polyaniline (PANI) was chemically grafted with chitosan by using ammonium peroxydisulfate (APS) initiator to obtain a product called as chitosan-graft-polyaniline (CHIT-g-PANI). Polyaniline, chitosan and CHIT-g-PANI were characterized by fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, X-Ray diffraction (XRD) and scanning electron microscopy (SEM). UV –vis and FT-IR studies confirmed the chemical structure and conjugation of CHIT-g-PANI. FTIR studies suggested the graft copolymerization of polyaniline on to chitosan. XRD of the CHIT-g-PANI further evidenced the grafting. The surface structure of CHIT-g-PANI was also verified by SEM.

In this work, an attempt was made to synthesize chalcones 3-(Substitutedphenyl)-N-(4H-1,2,4-triazol-4-yl)acrylamide by condensation of Substitutedbenzaldehyde with N-(4H-1,2,4-triazol-4-yl)acetamide under basic conditions by using both conventional and Microwave synthesis methods. A simple condensation reaction of substiutedbenzaldehyde and N-(4H-1,2,4-triazol-4-yl)acetamide using Sodium hydroxide as a base was carried out for the study. The synthesized chalcone derivatives were characterized for FTIR, 1H NMR, 13C NMR and Mass spectral analysis. It was observed that complete conversion to chalcone occurred in 10-12 min by Microwave synthesis method and in 10 h by conventional method. Finally, it has been observed that chalcone synthesis using Microwave synthesis method is a Convenient, Rapid and Eco-Friendly Synthesis over conventional method. The reaction time has been brought down from hours to seconds with improved yield as compared to conventional heating.

Non-traditional method (grinding) was used for the preparation of novel schiff bases from 4-amino-3-methyl phenol / 2-amino-4-methyl phenol and several aldehydes and ketones under catalytically free condition. This procedure constitutes an energy efficient, shorter time, higher yield as well as green synthesis approach. Some synthesized products were characterized by IR, NMR and MASS and also tested for antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Klebsiella pneumonae) activities by disc diffusion method

The Baylis-Hillmann reaction of 8-formyl-7-hydroxy furyl chromones on react with Acrylonitrile in DABCO/CHCl3 medium under nitrogen atmosphere at room temperature gives of 2-(2-furyl)-3-methyl-4oxo-4H,8H-pyrano[2,3-f]chromene-9-carbonitrilies (4a-h) in good yields.

Novel series of compounds containing 2-(2-substituted benzylidene hydrazinyl)-4-(4-(4-methoxyphenyl) piperazin-1-yl)-6-(4-tolyl oxy)-1,3,5-triazine (s-triazine) derivatives were synthesized. The formed compounds have been evaluated by physical methods (melting point, TLC, elemental analyses) and upon spectral data (IR and NMR). The newly synthesized compounds were also evaluated for antimicrobial activity against variety of bacterial strains in which some of these derivatives exhibited potential antibacterial and antifungal activity.

Pyrano[2,3-b]quinolin-2-ones was synthesized by cyclic condensation of 2-chloro-3-formylquinolines with sodium acetate and acetic acid in microwave reactor. Microwave reactions are very inexpensive, operational simplicity, eco-friendly method and good yield in a very short reaction time. Unexpectedly, 3-formylquinolin-2(1H)-ones were exclusively formed in very high yield by changing the molar ratio of acetic acid and sodium acetate in just 1.5 to 2.5 min. The synthesized compounds were characterised by IR, NMR, and Mass Spectra.

A series of substituted styryl 5-methyl-2-furyl ketones have been synthesized by closed-aldol reaction. The purities of these chalcones were checked by their physical constants and spectral data published earlier in literature.  The insect antifeedant activities of these ketones were studied using 4^th instar larvae Achoea Janata L with castor leaf discs.