An efficient synthesis of quinazoline derivatives with the aid of low-valent titanium reagent
作者:Daqing Shi、Chunling Shi、Juxian Wang、Liangce Rong、Qiya Zhuang、Xiangshan Wang
DOI:10.1002/jhet.5570420201
日期:2005.3
Quinazolin-4(3H)-ones, 1,2-dihydroquinazolin-4(3H)-ones, 3,4-dihydroquinazolines, imidazo[1,2-c]-quinazolines and 5,6-dihydroimidazo[1,2-c]quinazolines were synthesized by the novel reductive reaction of nitro group, N-H bond and ortho-ester, aldehydes or ketones promoted by the low-valenttitaniumreagent (TiCl4-Zn system). The structures of these compounds were characterized by elemental analysis
喹唑啉-4(3 H)-one,1,2-二氢喹唑啉-4(3 H)-one,3,4-二氢喹唑啉,咪唑并[1,2- c ]-喹唑啉和5,6-二氢咪唑并[1,2 - c ^ ]喹唑啉通过将低价钛试剂(促进的TiCl硝基,NH键和原酸酯,醛或酮的新型还原反应,合成4 -Zn系统)。这些化合物的结构通过元素分析,IR和1 HNMR光谱进行表征,并通过单晶X射线衍射分析进一步证实。
An efficient synthesis of quinazoline-2,4-dione derivatives with the aid of a low-valent titanium reagent
作者:Da-Qing Shi、Guo-Lan Dou、Zheng-Yi Li、Sai-Nan Ni、Xiao-Yue Li、Xiang-Shan Wang、Hui Wu、Shun-Jun Ji
DOI:10.1016/j.tet.2007.07.011
日期:2007.9
A facile synthetic method using low-valenttitaniumreagent (TiCl4/Zn system) to promote the novel reductive cyclization of 2-nitrobenzamides and triphosgene is described. Sequentially, a series of quinazoline-2,4-diones were synthesized in good yields.
An efficient synthesis of 2H-indazoles via reductive cyclization of 2-nitrobenzylamines induced by low-valent titanium reagent
作者:Fang Sun、Xian Feng、Xuan Zhao、Zhi-Bin Huang、Da-Qing Shi
DOI:10.1016/j.tet.2012.03.043
日期:2012.5
An efficient and improved synthesis of 2H-indazoles via reductive cyclization of 2-nitrobenzylamines induced by low-valenttitaniumreagent (TiCl4/Zn) is described. In this reaction triethylamine (TEA) was used to control the pH value. This method has the advantages of easily accessible starting materials, convenient manipulation, higher yield, shorter reaction time, and wider substrate scope.
Synthesis of Quinazolines and Imidazo[1,2-<i>c</i>]quinazolines with the Aid of a Low-Valent Titanium Reagent
作者:Daqing Shi、Juxian Wang、Chunling Shi、Liangce Rong、Qiya Zhuang、Hongwen Hu
DOI:10.1055/s-2004-822893
日期:——
A short and facile synthesis of a series of quinazolines and imidazo[1,2-c]quinazolines was accomplished in good yields via the novel reductive cyclization of 2-nitrobenzyl amines or 2-(2-nitrophenyl)imidazoles with ortho-ester, aldehydes or ketones promoted by TiCl4/Zn system. The structures were established by spectroscopic data and confirmed by X-ray analysis.
Therapies based on urease inhibition are now seriously considered as the first line of treatment for infections caused by Helicobacter pylori. However, the present inhibitors are ineffective or unstable in highly acidic gastric juice. Here, we report a series of benzylanilines as effective inhibitors of H. pylori urease. Out of the obtained twenty-one compounds, N-(3,4-dihydroxybenzyl)-4-nitroaniline (4) was evaluated in detail and shows promising features for development as anti-H. pylori agent. Excellent potency against urease in both cell-free extract and intact cell was observed at low concentrations of 4 (IC50 = 0.62 +/- 0.04 and 1.92 +/- 0.09 mu M), which showed over 29- and 54-fold increase in potency with respect to the positive control AHA. The SAR analysis revealed that protection of 3,4-dihydroxy group of 4 as methoxy or changes of 4-NO2 will result in a moderate to dramatic decrease in potency. (C) 2015 Elsevier Ltd. All rights reserved.