Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction
摘要:
An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a-g and imidazo[1,5-a]quinoxalines 7a-h by the reaction of 2-imidazolyl anilines 4a-c with aryl aldehydes 5a-k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a-b was found to be instrumental for the success of the reaction. (C) 2013 Elsevier Ltd. All rights reserved.
Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi’s Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
摘要:
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Lewis Acid-Catalyzed Selective Synthesis of Diversely Substituted Indolo- and Pyrrolo[1,2-a]quinoxalines and Quinoxalinones by Modified Pictet-Spengler Reaction
作者:Akhilesh K. Verma、Rajeev R. Jha、V. Kasi Sankar、Trapti Aggarwal、Rajendra P. Singh、Ramesh Chandra
DOI:10.1002/ejoc.201101013
日期:2011.12
An efficient tandem process for the selectivesynthesis of 1,2-annulated α-fused quinoxalines using benzotriazole methodology by a modifiedPictet–Spenglerreaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6-endo-dig-cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature
Novel compounds possessing potent cAMP and cGMP phosphodiesterase inhibitory activity. Synthesis and cardiovascular effects of a series of imidazo[1,2-a]quinoxalinones and imidazo[1,5-a]quinoxalinones and their aza analogs
作者:David D. Davey、P. W. Erhardt、E. H. Cantor、S. S. Greenberg、W. R. Ingebretsen、J. Wiggins
DOI:10.1021/jm00113a002
日期:1991.9
A series of novel imidazoquinoxalinones and their aza analogues were prepared by the cyclization of o-amino(H-1-imidazol-1-yl)aryls and heteroaryls with carbonyldiimidazole. The compounds were screened for inhibition of Type I and Type IV phosphodiesterases (PDE's) and evaluated for their vasorelaxant and positive inotropic activities in vitro. In general, compounds having potent PDE inhibitory activity also possessed good inotropic and vasodilator activity, although linear correlations between these activities could not be established.