Synthesis and Biological Evaluation of some Important Heterocycles as possible Drug Candidates

This thesis describes about the synthesis of some heterocyclic compounds, such as isobenzofuran-1-one, benzophenone, tetrahydroisoqunoline, furan and hydroxychavicol derivatives in very good yields. This thesis also depicts the results of these heterocyclic compounds against various biological activities such as inhibition of soybean lipoxygenase (SB-LOX), and also antiparkinson‟s, anti-cancer activities, anti-microbial and anti-leishmanial activities. The mild and efficient iodine catalyzed one pot synthesis of isobenzofuran-1-one and benzophenone derivatives were achieved with good yields. Among the synthesized isobenzofuran-1-one derivatives,five of them showed anti-leshmanial activit with IC50 14.25 μM and 16.72 μM respectively for 4-chloro phenyl substituted isobenzofuran-1-one and 4-methyl phenyl substituted benzophenone. Further screening of all the compounds in-vitro and in-vivo for anti-leishmanial activity may lead potent anti-leishmanial drugs. The inhibitory activity against soybean lipoxygenase (SB-LOX) of furan derivatives were investigated by in-vitro experiment 5-(4-Bromo-phenyl)-4-[2-(4-bromo-phenyl)-2-oxo-ethyl]-2-methyl-furan-3-carboxylic acid ethyl esters was found to be the most active compound among various derivatives of furan. This observation was validated by carrying out docking studies using AutoDock 4.0. The entire synthesized compounds were found to be selective inhibitors of the gram-positive bacteria such as S. aureus and B. subtilis with the MIC of 1.1- 2.9 M except. Further pharmacological studies of 2-Methyl-4- (2-oxo-2-phenyl-ethyl)-5-phenyl-furan-3-carboxylic acid ethyl ester derivatives may lead to develop novel anti-inflammatory as well as anti-bacterial agents. The tetrahydroisoquinoline derivatives were synthesized with good yields, and synthesized derivatives were screened for anti-Parkinson‟s disease by in–vivo animal model. Thus tetrahydroisoquinolines possesses significant antiparkinsonian properties and has got ability to target diverse molecular and cellular events implicated in the pathophysiology of PD together makes that these synthetic tetrahydroisoquinoline derivatives could be extremely desirable molecules for further investigation as new drug entity for the treatment of this neurological disorder. The hydroxychavicol analogues have been synthesized efficiently, and all the compounds were screened for broad-spectrum anti-cancer activity. They showed good anticancer activity by both in-vitro and in-vivo models. Further studies on these compounds may lead to develop potent anticancer drug. Overall, the preliminary results obtained in this research work once again suggest that the heterocyclic compounds posses enormous biological activities .Further detailed Pharmacological studies may lead to develop potential drug candidates against studied diseases. Part of these results have already been published in journals and filed International patents.Biologically active heterocyclic compounds: A Review Introduction Heterocycles form, by far, the largest of the classical divisions of organic chemistry. Moreover, they are of immense importance not only biologically and industrially but also for the functioning of any developed human society as well. Their participation in a wide range of areas cannot be under estimated. The majority of pharmaceutical products that mimic natural products with biological activity are heterocycles. Therefore, researchers are on a continuous pursuit to design and produce better pharmaceuticals, pesticides, insecticides, rodenticides, and weed killers by following natural models. Heterocycles play a major part in biochemical processes and are also side groups of the most typical and essential constituents of living cells. Other important practical applications of these compounds can also be cited, for instance, their use as additives and modifiers in a wide variety of industries including cosmetics, reprography, information storage, plastics, solvents, antioxidants, and vulcanization accelerators. Finally, as an applied science, heterocyclic chemistry is an inexhaustible resource of novel compounds