A. Nagaraj

Synthesis and biological study of novel bis-chalcones, bis-thiazines and bis-pyrimidines

A series of novel bis-chalcones 3 were prepared by the reaction of 5,5′-methylene-bis-salicylaldehyde 2 with various acetophenones, subsequent treatment of 3 with thiourea or guanidine resulted to the corresponding bis-thiazines or bispyrimidines in good yields. All the new compounds have been characterized by IR, 1H NMR, MS and elemental analysis. The antibacterial, antifungal and anti-inflammatory activities of the compounds have also been evaluated.

Synthesis and in vitro study of methylene-bis-tetrahydro[1,3]thiazolo[4,5-c]isoxazoles as potential nematicidal agents

A series of methylene-bis-tetrahydro[1,3]thiazolo[4,5-c]isoxazoles 6 were synthesized by the reaction of chalcone derivative of methylene-bis-thiazolidinone 5 with hydroxylamine hydrochloride. The chemical structures of newly synthesized compounds were elucidated by IR, 1H, 13C NMR, MS and elemental analyses. The compounds 6a-g were evaluated for their nematicidal activity against Ditylenchus myceliophagus and Caenorhabditis elegans, compound 6e and 6f showed appreciable nematicidal activity. Further the compounds 6a-g were screened for their antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185) and Trichophyton mentagrophytes (IFO 40996). The compounds 6b and 6f displayed notable antifungal activity against all the microorganisms employed. The activity of these two compounds is almost equal to the standard. It is also interesting to note that the compounds 6b, 6f and 6g showed activity towards C. albicans at the concentration of 3.75 microM, which is less than the concentration of the standard Amphotericin B.

ZIRCONIUM OXYCHLORIDE AS A NEW AND EFFICIENT CATALYST FOR THE SYNTHESIS OF 3,4-DIHYDROPYRIMIDINE-2(1H)- THIONE/ONE UNDER SOLVENT-FREE MICROWAVE IRRADIATION CONDITIONS

Abst rac t : ZrOCl2 has been found to be an efficient catalyst for the one-pot synthesis of 3,4dihydropyrimidine-2(lH)-thione/one, from ß-ketoester, aldehyde and (thio)urea under solvent-free microwave irradiation conditions. The beneficial effects of ZrOCl2 / microwave irradiation on the reaction are described. This is the first report on Lewis base catalyzed Biginelli reaction.