Highly regioselective direct halogenation: a simple and efficient method for preparing 4-halomethyl-5-methyl-2-aryl-1,3-thiazoles
摘要:
An unprecedented C4-methyl regioselective halogenation of 4,5-dimethyl-2-aryl-1,3-thiazoles (1) has been accomplished. The reaction of compound 1 with N-chlorosuccinimide and N-bromosuccinimide under mild conditions provides an efficient and operationally simple method for obtaining 4-chloromethyl-5-methyl-2-aryl-1,3-thiazoles (2) and 4-bromomethyl-5-methyl-2-aryl-1,3-thiazoles (3), respectively, in good yields without the formation of 4-methyl-5-halomethyl regioisomers. (C) 2003 Elsevier Ltd. All rights reserved.
compounds were fully characterized by 1H, 13C1H} NMR and FT-IR spectra. The structures of 2c, 2d, and 2e were determined by X-ray crystallography and the prepared complexes (2a-e) were investigated as catalysts for the direct arylation of 2-n-propylthiazole, 4,5-dimethylthiazole and 2-acetylthiophene with various aryl bromides. High catalytic activity for arylation was seen reaction using only 0.5 mol%
在富含电子的杂芳烃的情况下,可以使用芳基卤化物活化特定的C H键进行芳基化,而无需指导该基团。容易产生卤素取代的芳基化杂芳烃的能力在有机化学中很重要,因为这些物种是生物化学家的重要组成部分。在此手稿中,我们报告了PEPPSI型新型苯并咪唑基N-杂环卡宾-钯(II)配合物(2a-e)的合成。所有这些新化合物均通过1 H,13 C 1 H} NMR和FT-IR光谱进行了全面表征。通过X射线晶体学确定2c,2d和2e的结构,并制备配合物(研究了2a-e)作为2-正丙基噻唑,4,5-二甲基噻唑和2-乙酰基噻吩与各种芳基溴直接芳基化的催化剂。仅使用0.5mol%的催化剂反应1小时,观察到高的芳基化催化活性。
Palladium(II)- N -heterocyclic carbene-catalyzed direct C2- or C5-arylation of thiazoles with aryl bromides
作者:Murat Kaloğlu、İsmail Özdemir
DOI:10.1016/j.tet.2018.03.026
日期:2018.6
their corresponding palladium(II)-NHC complexes with the general formula [PdCl2(NHC)2] were synthesized. All new compounds were characterized by 1H NMR, 13C NMR, IR spectroscopy and elemental analysis techniques. The catalytic activity of palladium(II)-NHC complexes was investigated in the direct C2- or C5-arylation of thiazoles with aryl bromides in presence of palladium(II)-NHC at 150 °C for 1 h. These
在此我们报道,合成了一系列新的苯并咪唑氯化物作为N-杂环卡宾(NHC)配体及其相应的通式为[PdCl 2(NHC)2 ]的钯(II)-NHC配合物。所有新化合物均通过1 H NMR,13 C NMR,IR光谱和元素分析技术进行表征。在钯(II)-NHC的存在下于150°C进行1 h的噻唑与芳基溴的直接C2-或C5-芳基化反应中,研究了钯(II)-NHC配合物的催化活性。这些配合物对噻唑直接芳基化表现出良好的催化性能。噻唑的芳基化以中等至高产率选择性地产生C 2或C 5芳基化的噻唑。
Synthesis, structures and catalytic activity of Pd(II) saccharinate complexes with monophosphines in direct arylation of five-membered heteroarenes with aryl bromides
作者:Veysel T. Yilmaz、Ceyda Icsel、Omer R. Turgut、Muhittin Aygun、Enes Evren、Ismail Ozdemir
4,5‐Dihydro‐imidazol‐2‐ylidene‐linked palladium complexes as catalysts for the direct CH bond arylation of azoles
作者:Murat Kaloğlu、Namık Özdemir、İsmail Özdemir
DOI:10.1002/aoc.6551
日期:——
In most of previous studies catalyzed by such complexes, unsaturated ring carbene ligands such as benzo[d]imidazol-2-ylidene and imidazol-2-ylidene were used. However, the use of saturatedring carbene ligands such as 4,5-dihydro-imidazol-2-ylidene has been highly limited. Therefore, in this study, four novel 4,5-dihydro-1H-imidazolium salts were synthesized as saturatedring carbene precursors. Then
by homogeneous Pd-catalyzed directarylation is an important research topic in modern organic chemistry. In this study, PEPPSI-type, (PEPPSI = Pyridine Enhanced Precatalyst Preparation Stabilization and Initiation), new Pd-catalysts with N-heterocyclic carbene ligand were synthesized, and they were used as catalysts in the synthesis of bi(hetero)arenes by directarylation process. The structures of
摘要 由于双(杂)芳烃在工业上的重要性,通过均相 Pd 催化直接芳基化合成这些化合物是现代有机化学中的一个重要研究课题。本研究合成了具有 N-杂环卡宾配体的新型 Pd 催化剂,PEPPSI 型(PEPPSI = Pyridine Enhanced Precatalyst Prepared Stabilization and Initiation),并将它们用作直接合成双(杂)芳烃的催化剂。芳基化过程。Pd-卡宾配合物的结构通过不同的光谱和分析技术,如NMR、FT-IR和元素分析来阐明。通过单晶 X 射线衍射研究确定了其中一种配合物的更详细的结构特征。