Date of Award
1-1-2011
Thesis Type
phd
Document Type
Thesis
Divisions
science
Department
Dept of Chemistry
Institution
University of Malaya
Abstract
Flavonoids are a class of natural products that are well known to possess a wide range of pharmacological properties. Due to their recent discovery in modulating muscarinic receptor activity and its inhibitory effect against dengue-2 virus NS3 protease, flavonoids are idea candidates for drug development. This dissertation describes the syntheses of several flavones and some Diels-Alder adducts derived from chalcones. A modified Baker-Venkataraman method has been developed where flavones were prepared in a one-pot procedure from the corresponding 2-hydroxyacetophenones and acyl chlorides under different conditions. When 2-hydroxyacetophenone is heated with a stoichiometric amount of acyl chloride, either in a DBU/pyridine system or in an open K2CO3/acetone system, only the flavone is obtained, albeit in modest yield. However, when it is heated with an excess of acyl chloride in a DBU/pyridine system, the 3-acylflavone is the only product, while treatment in an open K2CO3/acetone system afforded the flavone as the major product and a smaller amount of 3-aroylflavone. Panduratin A and its regioisomer isopanduratin A have been synthesized in four steps from (E)-ocimene, [(E)-3,7-dimethyl-1,3,6-octatriene] via a Diels–Alder cycloaddition reaction. An overall yield of 75% was achieved from 2,6-dihydroxy,4-methoxyacetophenone. The mulberry Diels-Alder adducts pentamethyl ethers of the kuwanon V and dorsterone have been synthesised via a biomimetic intermolecular [4+2] cycloaddition reaction between a highly electron-rich dienophile and a Lewis acid sensitive diene derived from chalcone. Cycloaddition reaction under thermal condition afforded the kuwanon V and dorsterone in a 3:2 ratio. Cycloaddition catalysed by AgOTf/Bu4NBH4 gave higher yield of adducts.
Note
Thesis submitted in fulfillment of the requirement for the degree of Doctor of Philosophy
Recommended Citation
Chee, Chin Fei, "Synthesis of bioactive cyclohexenyl chalcones and flavonoid derivatives / Chee Chin Fei" (2011). Student Works (2010-2019). 595.
https://knova.um.edu.my/student_works_2010s/595