Scaffold-directed and traceless synthesis of tricyclic quinoxalinone imidazoles under microwave irradiation: for SCS-09 special issue-combinatorial approaches to drug discovery.

Suman Thummanagoti, Chih-Hau Chen, Zhan-Hui Xu, Chung-Ming Sun

Index: Mol. Divers. 15(1) , 101-7, (2011)

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Abstract

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.