Preparation of 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-ones by palladium-assisted internal biaryl coupling reaction
作者:Yohei Ikuma、Hiroyuki Nakahira
DOI:10.1016/j.tet.2011.10.015
日期:2011.12
Representatives of the 3H-imidazo[4,5-c]quinolin-4(5H)-ones have shown interesting biological activity. We have found 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-one as a potent dipeptidyl peptidase 4 inhibitor. However effective synthesis of this nucleus with various substituents at the 6-9-positions has not been reported. We report herein the development of a novel and efficient synthesis of 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-ones by palladium-assisted internal biaryl coupling reaction. Our optimization of the reaction conditions revealed that the most important factors for this reaction are use of silver carbonate as a base and high reaction temperature. (C) 2011 Elsevier Ltd. All rights reserved.