SYNTHESIS OF NITROGEN HETEROCYCLES OF BIOLOGICAL, PESTICIDAL AND SYNERGISTIC INTEREST

Abstract

Population explosion has led to important contributions in the area of food and health. Enormous increase in the population of the world has called for a new order with great emphasis on search for more food, drugs and pesticides. In these efforts scientific and technological inputs have greatly helped to increase the food production which calls for the use of pesticides for better yield, to avoid losses, damage and use of syner gists to reduce the toxicity of pesticides. It is interesting to observe that many heterocyclic ring systems containing Nitrogen and Sulphur have received considerable attention in search of Pesticides, Drugs and Pharma ceuticals . As a part of continuing programme in the areas of pesticides and biologically active molecules in this laboratory, a number of fused heterocyclic ring systems have been synthesized and evaluated for their biological and pesticidal actions. A number of interesting leads obtained belong to 4(3H)-quinazolinones , phthalazines, oxadiazoles and related compounds. Broad spectrum of activity observed in these ring systems belong to central nervous system (CNS) depresent action, analgesic, antiinflamma tory, antibacterial and antifungal actions. In view of these increasing observations, it has been considered of interest to synthesize various heterocyclic systems incorporating Nitrogen, Sulphur and Oxygen. The programme of work carried out has been presented as follows: CHAPTER I describes salient features of available data in literature concerning various heterocyclic ring systems such as triazoles and fused triazoles. CHAPTER II incorporates the synthesis of members belonging to benzylideneaminotriazoles and triazolothiadiazoles having a variety of substitutions. CHAPTER III deals with substituted and fused triazole ring systems such as triazolothiadiazines and thiazolotriazoles. CHAPTER IV highlights the synthesis of various compounds derived from benzimidazoles. All the compounds synthesized in the course of present investi gation have been identified by their elemental analysis and spectral studies ,such as IR, PMR and Mass spectra. In view of the structural; novelty of the compounds synthesized in CHAPTERS II, III and IV, selected candidate members have been subjected to biological, pesticidal and synergistic actions. Biological activity has been tested in experimental animals for their action on CNS, analgesic, anti inflammatory and related actions. Pesticidal activity has been confined to the study of synergism with fungicides such as 2-methylbenzimidazol, carbamate (MBC) and insecticide such as carbaryl. These findings have been incorporated in CHAPTER V of this thesis. Since the testing for biological activity and pesticidal activity is time consuming and depends on many factors such as availability of experimental animals etc., efforts have been made to include reports received till the time of writing.