Synthesis of 2-aryl-2H-[1,2,4]triazoloquinolin-3-one and 2-aryl-2H-[1,2,4]triazoloisoquinolin-3-one derivatives from α-chloroformylarylhydrazines hydrochloride
作者:Jiann-Jyh Huang、Kun-Lung Chen、Yu-Shiang Lin、Sheng-Chuan Yang、Shih-Hsien Chuang、Kuo-Chen Chiang、Wen-Che Tseng、Fung Fuh Wong、Mou-Yung Yeh
DOI:10.1016/j.tet.2009.11.095
日期:2010.1
The reaction of alpha-chloroformylarylhydrazines hydrochloride with quinoline under air provided the corresponding 2 -ary1-2H-[1,2,4] triazoloquinolin-3-ones 3a-3d in 33-42% yields and unexpected isomeric 2-aryl-2H-[1,2,4]triazoloisoquinolin-3-ones 4a-4d in 30-42% yields. These two isomers were isolated and fully characterized by spectroscopic methods including X-ray crystallography. By employing 3-methylquinoline as the starting material under the same condition, the reaction only gave compound 3e-3h as sole products in 70-82% yields without the formation of isomers. A plausible mechanism was proposed through electrophilic aromatic reaction, the tandem ring cyclization and ring-opening, and oxidation for the generation of 2-aryl-2H-[ 1,2,4]triazoloisoquinolin-3-ones (4). Crown Copyright (C) 2009 Published by Elsevier Ltd, All rights reserved.