Browsing by Author "Paike, Vijaykumar"

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Microwave-Assisted Multicomponent Synthesis of Dihydroquinoxalinones on Soluble Polymer Support
(2015-07-01)
Dalvi, Prashant B.
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Lin, Shu-Fen
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Paike, Vijaykumar
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Sun, Chung-Ming
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應用化學系
A one-pot and two-step reaction of four components, including aldehydes, Fmoc-protected alpha-amino acid, isocyanide, and soluble polymer-supported 4-fluoro-3-amino benzoate ester, was developed for an efficient synthesis of dihydroquinoxalinones under microwave irradiation. Fmoc deprotection followed by intramolecular cyclization of the diamide gave a facile access to novel bicyclic quinoxalin-2-ones. On the basis of this approach, a new route to synthesize this privileged scaffold from the diamide intermediate was designed and accomplished with high yields. Use of multicomponent reaction (MCR) has been shown to display a good functional group tolerance, while the product isolation and purification is straightforward by precipitation and washings. Current library discusses the synthesis and diversification of 21 compounds produced using this strategy.
One pot three component reaction for the rapid synthesis of pyrrolo[1,2-a]benzimidazoles
(2013-05-01)
Hsu, Wei-Shun
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Paike, Vijaykumar
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Sun, Chung-Ming
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應用化學系
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Department of Applied Chemistry
An efficient strategy for the synthesis of pyrrolo[1,2-]-benzimidazole (PBI) linked to an ionic liquid (ILs) as a soluble support under microwave irradiation was explored. The key intermediate benzimidazoles were synthesized via N-acylation followed by cyclodehydration of IL-supported methyl-3-amino-4-(isobutylamino) benzoate. The synthesis of the IL-bound PBI was performed by one-pot three-component condensation under microwave dielectric heating, which involved a Knoevenagel condensation and a [4+1]-cycloaddition reaction. The reaction was monitored directly by means of H NMR. All final products were obtained in good yield and high purity after precipitation.
Palladium-catalyzed regioselective synthesis of 2(2 '-biphenyl)benzimidazoles through C-H activation
(2013-11-01)
Chen, Li-Hsun
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Wu, Tz-Yi
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Paike, Vijaykumar
;
Sun, Chung-Ming
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應用化學系
An efficient palladium-catalyzed strategy through C-H bond activation for the synthesis of 2(2-biphenyl)-benzimidazoles is reported herein. The regioselective C-C bond formation proceeds in a sealed tube via oxidative C-H activation of ortho-directed 2-aryl-benzimidazole to couple with various iodobenzene analogs in high yields. This arylation exhibited high regioselectivity which is able to increase molecular diversity in difficult functionalized positions of parent molecules. This strategy provides a convenient and simple synthesis of biphenyl heterocyclic compounds with high regioselectivity.
Rapid synthesis of novel isoindolo[1,2-a] quinazoline on ionic liquid support under microwave irradiation
(2013-06-01)
Jedhe, Ramchandra
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Paike, Vijaykumar
;
Sun, Chung-Ming
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應用化學系
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Department of Applied Chemistry
An efficient ionic liquid-supported (ILs) strategy is applied for the synthesis of substituted isoindolo[1,2-a] quinazoline under microwave irradiation. The ILs enhances the coupling capability of microwave flash heating in green organic synthesis. The acid-catalyzed heterocyclization of ionic liquid bounded 3-amino-4-[(alkylamino) methyl] benzoate was carried out with alpha-ketobenzoic acids or gamma-ketoaliphatic acid to synthesize five and six member fused N-heterocycles. The one-pot heterocyclization proceeded via amidation between primary amines and 2-acylbenzoic acids or gamma-ketoaliphatic acid, followed by the intramolecular dehydrocyclization with the keto group under microwave heating. The significant advantages in green synthesis by using ILs synthesis under controlled microwave dielectric heating are the dramatic reduction in reaction time, improved energy utilization, simple purification, and increasing the productivity of desired compounds.