2-Pyranones-Derived Arenes and Heteroarenes as Biodynamic Agents
IR@CDRI: CSIR-Central Drug Research Institute, Lucknow
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| Creator |
Verma, Deepti
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| Date |
2014-01-24T10:46:16Z
2014-01-24T10:46:16Z 2008 |
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http://hdl.handle.net/123456789/1190
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| Description |
Guide- Dr. Atul Goel, Ph.d Thesis Submitted to JNU, New Delhi in 2008
Pyran ring system is widely present in animal and plant kingdom and possesses diverse pharmacological activities. Pyran is a six-membered oxygen heterocycle with two double bonds. Out of five carbon atoms of pyran ring, four are sp2 carbons and one is sp3 hybridized. Pyran ring is not a true aromatic ring. In the nomenclature of this ring system, the position of sp3 carbon is designated by adding ‘H’ or in other words the use of suffix ‘H’ locates the positions of the double bonds. In this thesis, we mainly worked on synthon 2H-pyran-2-one and their utility for the synthesis of various arenes and heteroarenes. As evident from the topography of 2H-pyran-2-one that C-2, C-4 and C-6 positions of 2H-pyran-2-one ring are electrophilic in nature and prone to nucleophilic attack. The electron density at the positions C-3 and C-5 remains unaffected and these positions are susceptible to electrophilic attack. Presence of electron releasing substituents at C-4 and C-6 positions of the pyran ring facilitates the electrophilic substitution in the ring. Electron withdrawing substituent at position C-3 makes the position C-4 and C-6 more impoverish and thereby favours the nucleophilic reactions. Between these two positions latter is comparatively more susceptible to nucleophile. Presence of good leaving groups such as methoxy, methylsulfanyl and methylsulfoxide group at C-4 makes the position more vulnerable for nucleophilic reactions. In search of novel arenes and heteroarenes of synthetic and biological potential, we have rationally designed and synthesized different classes of compounds in anticipation to have better efficacy with no adverse effects through ring transformation of 2H-pyran-2-ones under mild reaction conditions. The entire work presented in this thesis has been divided into five chapters. The first chapter consists of an overview of 2H-pyran-2-ones and its utility for the synthesis of various types of arenes and heteroarenes. This chapter discussed about the properties and topography of pyran-2-one. It also includes a broad range of ring transformation reactions for the formation of various types of aromatic scaffolds such as monocyclic-, bicyclic-, polycyclic arenes, nitrogen-, sulfur- and oxygen-containing heterocycles and some organometallic compounds. The second chapter delineates the synthesis of various biaryls functionalized with electron donating and withdrawing groups through ring transformation reactions of various 2Hpyran-2-ones by alkylaldehydes, acetyltrimethylsilane, (benzylthio)acetone, acetonylacetone,3,3-dimethoxybutane-2-one, S-(-)-citronellal and pseudoionone as nucleophilic source and these compounds are also evaluated for their biodynamic properties. Third chapter includes the synthesis of various functionalized ortho-, meta- and parateraryls and quarteraryl prepared through ring transformation strategy. These compound are evaluated for antihyperglycemic activity. Fourth Chapter of the thesis describes synthesis of ferrocenylarenes prepared by ring transformation of 6-ferrocenyl-2H-pyran-2-ones with various nucleophiles such as acetyltrimethylsilane and alkyl aldehydes viz propanal and butanal. The fifth chapter includes the synthesis of new type of precursor 5,6-dihydro-2-oxo-4-sec. amino-2H-benzo[h]chromene-3-carbonitriles and utilized them for the formation of polycyclic aromatic and heteroaromatics. In this chapter we discussed the synthesis of 4-benzylsulfanyl-3-methyl-1-sec.amino-9,10-bihydrophenanthrene-2-carbonitriles, 3-(1,1- dimethoxyethyl)-1-sec.amino-9,10-dihydrophenanthrene-2-carbonitriles, 3-acetyl-1-sec.amino-9,10-dihydrophenanthrene-2-carbonitriles and (S)-4-(6-methylhept-5-en-2-yl)-1-sec.amino-9,10-dihydrophenanthrene-2-carbonitriles as well as oxahelicenes constructed through ring transformation strategy using 5,6-dihydro-2-oxo-4-sec.amino-2H-benzo[h]chromene-3-carbonitriles as precursors. We also explored their biological activities in in vitro and in vivo systems. |
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4482564 bytes
application/pdf |
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| Language |
en
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CSIR-CDRI Thesis No.-V-18
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| Subject |
Heteroarenes
2-Pyranones-Derived Arenes Biodynamic Agents |
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| Title |
2-Pyranones-Derived Arenes and Heteroarenes as Biodynamic Agents
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| Type |
Thesis
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