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Authors: Bisht, Sushma
Advisor: Rajvir Singh
Title: Synthesis of some substituted carbamates, their nematicidal activity and dissipation of thiodicarb in soils
Publisher: CCSHAU
Language: en
Type: Thesis
Agrotags: Carbamates, Coumarins, Chalcones, Isoxaxoles, Pyrazoles, Nematicidal Activity, Persistence, Thiodicarb.
Abstract: Pesticides are a vital facet of farming because they enable us to produce sufficient high quality wholesome food for a growing population. They also allow efficient and economic pest control and often there is no alternative control option. We all benefit from these chemicals and therefore have a responsibility to ensure that these benefits are maximized and adverse effects are minimized. Keeping this in mind, the synthesis and characterization of 2H-1-benzopyran-2-ones (7-14), 3-(substitutedphenyl)-1-(2/3-hydroxyphenyl)-2-propen-1-ones (60-75), 2/3-[5-(substituted phenyl) isoxazol-3-yl phenols (142-157) and 2/3-[5-(substitutedphenyl)-4, 5-dihydro-1H-pyrazol-3-yl] phenols (207-222) and their carbamate derivatives were synthesized. The chemical structure of newly synthesized compounds was elucidated by 1 H NMR, IR and other physical and analytical data. The structure activity relation in the above evaluation studies was also investigated. The bioactive assay showed that compounds 1-{3-[5-(substituted phenyl) isoxazole-3-yl] phenoxy}-3-(4-chlorophenoxy) propane-2-oxo-phenylcarbamtes (198-205) were found highly active at all concentrations. Compounds 2/3-[5-(substitutedphenyl)-4,5-dihydro-1H-pyrazol-3-yl]phenyl phenyl carbamates(223-238)showed moderate activity. All other compounds werealso active at tested highest concentration. The compounds showed spectacular prospects for further research and use in this field. The findings suggested that the isoxazoles and pyrazoles framework is an attractive template for synthesis of nematicides. These compounds needs further exploration for their possible use as nematicides and deserve further investigation. A lab experimentwas conducted to study the dissipation of thiodicarb in soils. It was concluded that thiodicarb residues reached below detectable level of 0.005 mg kg-1 within 15 days and 30 days in sandy loam and clay loam soils,respectively following first order kinetics and half life period between 4-9 days. Complete dissipation of methomyl took place after 15 days in both the soils with half life period between 6-9 days. Thiodicarb with its metabolite, methomyl persisted upto 30 days with per cent dissipation of 85.71 and 82.69 in sandy loam and clay loam soils, respectively. Its dissipation followed first order kinetics with half life period between 6-8 days. The persistence was more at higher dose and methomyl persisted more than thiodicarb in both thedoses of clay loam and sandy loam soils. Thiodicarb along with its metabolite, methomyl persisted beyond 30 days in both the soils.
Subject: Chemistry
These Type: Ph.D
Issue Date: 2012
Appears in Collections:Theses

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