Browsing by Author "Xu, Zhan-Hui"

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Divergent ionic liquid supported synthesis of isolable guanidine linked quinoxalinone and benzodiamine
(2013-02-06)
Chen, Li-Hsun
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Xu, Zhan-Hui
;
Lin, Chun-Chung
;
Sun, Chung-Ming
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應用化學系
Ionic liquid supported synthesis of guanidine linked piperazine, diazepane, and aminomethylpiperidine to difluoroquinoxalinones and difluoro benzodiamine was achieved by two regioisomeric products. They were isolated from one pot reduction and intramolecular cyclization to afford quinoxalinone ring system with traceless cleavage of ionic liquid support. Besides, the ionic-supported other isomer was further cleaved in methanol. All the reactions were carried out on an ionic liquid support under various conditions to deliver biologically relevant scaffolds with high purity and excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.
Scaffold-directed and traceless synthesis of tricyclic quinoxalinone imidazoles under microwave irradiation
(2011-02-01)
Thummanagoti, Suman
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Chen, Chih-Hau
;
Xu, Zhan-Hui
;
Sun, Chung-Ming
;
應用化學系
Traceless synthesis of 2-aminoimidazoquinoxalinones has been performed on soluble polymer support under open-vessel microwave dielectric heating. The reaction progression is monitored directly by the conventional proton NMR which indicated no release of the substrate from the support. Fmoc-deprotected amino acid polymer conjugates react with 1,5-difluoro-2,4-dinitro benzene to yield polymer bound dinitro fluoro amines, which are further substituted by various primary amines to yield PEG-immobilized dinitrodiamines. Simultaneous reduction of aromatic meta-dinitro group leads to the traceless release of 2-quinoxalinones, followed by N-hetero cyclization with various isothiocyanates in the presence of mercury(II)chloride to furnish 2-aminoimidazoquinolinone rings with three points of diversity at rapid pace.