A traceless polymer-supported synthesis of 4-benzoylquinazolines was developed using the following commercially available building blocks: Fmoc-α-amino acids, 2-nitrobenzensulfonyl chlorides and α-bromoacetophenones. The acyclic intermediates underwent base-catalyzed rearrangement involving C–C and N–N bond formation followed by ring expansion and yielded resin-bound dihydroquinazoline-2-carboxylic
When a mixture of 4-chloroquinazoline (7), an aromatic aldehyde 6, sodium hydride, and a catalytic amount of 1, 3-dimethylbenzimidazolium iodide (1) in tetrahydrofuran (THF) was refluxed with stirring for an appropriate time, the chlorine atom of 7 was replaced with the aroyl group, and the 4-aroylquinazolines 10 were obtained in excellent yields. Similar treatments of 4-chloro-2-methylquinazoline (8) and 4-chloro-2-phenylquinazoline (9) led to the 4-aroyl-2-methylquinazolines 11 and the 4-aroyl-2-phenylquinazolines 12, respectively.Use of N, N-dimethylformamide (DMF) instead of THF as the reaction solvent in the above reaction reduced the reaction time and increased the yields of the ketones 10 and 12 as compared with those in THF.
Synthesis of indoles and quinazolines <i>via</i> additive-controlled selective C–H activation/annulation of <i>N</i>-arylamidines and sulfoxonium ylides
Selective synthesis of indoles and quinazolines was achieved through a precise control of C–H activation/annulation by changing additives.
通过改变添加剂,通过精确控制C-H活化/环化实现了对吲哚和喹唑啉的选择性合成。
Pd(0)-catalyzed benzylic arylation–oxidation of 4-methylquinazolines via sp3 C–H activation under air conditions
作者:Dan Zhao、Min-Xue Zhu、Yue Wang、Qi Shen、Jian-Xin Li
DOI:10.1039/c3ob41488d
日期:——
An efficient and selective Pd(0)-catalyzed sp3 CâH bond arylationâoxidation of 4-methylquinazolines is reported. The method enables the introduction of arylketone at the benzylic position of 4-methylquinazolines without the use of an additional directing group, and atmospheric oxygen is used as the sole oxidant.