本文报道了一种环境友好的电化学方法,该方法利用俘获作用和离域作用产生氮中心自由基(NCR)。通过改变电极材料的反应参数和原料溶解度,脱芳香化使选择性脱氢的CN与NN键形成反应成为可能。因此,吡啶[1,2- a ]苯并咪唑和四芳基肼构架是通过具有广泛普遍性的可持续的无过渡金属和外源氧化剂的策略制备的。生物活性测定表明,吡啶并[1,2- a ]苯并咪唑类化合物具有抗微生物活性和对人类癌细胞的细胞毒性。化合物21具有良好的光化学性质,具有大的斯托克斯位移(约130 nm),并成功应用于亚细胞成像。初步的机理研究和密度泛函理论(DFT)计算揭示了可能的反应途径。
2-Aminopyridines via Reaction of Pyridine N-Oxides and Activated Isocyanides
摘要:
A practical and efficient method for the synthesis of substituted 2-aminopyridines from pyridine N-oxides is reported. Yields of purified, isolated products of up to 84% are observed for the one-pot, two-step process. The reaction involves an in situ deprotection of an isolable N-formylaminopyridine intermediate and facilitates the synthesis of 2-aminopyridines for which other methods fail.
Cu-Catalyzed Couplings of Heteroaryl Primary Amines and (Hetero)aryl Bromides with 6-Hydroxypicolinamide Ligands
作者:David J. Bernhardson、Daniel W. Widlicka、Robert A. Singer
DOI:10.1021/acs.oprd.9b00195
日期:2019.8.16
chemoselectivity and rate. The use of K2CO3 as the base enabled selective C–N coupling of aryl bromides over arylchlorides with 2–5 mol % Cu at 80–120 °C. With K3PO4 as the base, arylchlorides are capable of undergoing C–N coupling, though 5–10 mol % Cu is required at 120–130 °C. Members of the ligand family are straightforward to prepare in one step from 6-hydroxypicolinic acid and the corresponding
已经确定了6-羟基吡啶甲酸酰胺配体家族是Cu催化的杂芳基溴化物和氯化物与杂芳基伯胺的偶联的有效支撑配体。C–N偶联是在80–120°C的DMSO或环丁砜中,以2-10 mol%CuI和支持配体的K 2 CO 3或K 3 PO 4为碱进行的。发现碱的强度对化学选择性和速率有影响。使用K 2 CO 3作为碱,可以在80–120°C的条件下,以2–5 mol%的Cu在芳基氯上进行芳基溴的选择性C–N偶联。含K 3 PO 4作为基础,芳基氯化物能够进行C–N偶联,尽管在120–130°C下需要5–10 mol%的Cu。配体家族的成员可以直接一步一步由6-羟基吡啶甲酸和相应的苯胺制备。
Iridium(III)-Catalyzed Tandem Annulation of Pyridine-Substituted Anilines and α-Cl Ketones for Obtaining 2-Arylindoles
readily available N-(2-pyridyl)anilines and commercially available α-Cl ketones through iridium-catalyzed C–H activation and cyclization is reported here. As a complementary approach to the conventional strategies for indole synthesis, the transformation exhibits powerful reactivity, tolerates a large number of functional groups, and proceeds with good to excellent yields undermildconditions, providing
Direct C–H alkylation and indole formation of anilines with diazo compounds under rhodium catalysis
作者:Neeraj Kumar Mishra、Miji Choi、Hyeim Jo、Yongguk Oh、Satyasheel Sharma、Sang Hoon Han、Taejoo Jeong、Sangil Han、Seok-Yong Lee、In Su Kim
DOI:10.1039/c5cc07767b
日期:——
The rhodium(III)-catalyzed direct functionalization of aniline C-H bonds with [small alpha]-diazo compounds is described. These transformations provide the facile construction of ortho-alkylated anilines with diazo malonates or highly substituted indoles with...
A cascade iridium-catalysed oxindolesynthesis was achieved using pyridyl-protected anilines and bis(2,2,2-trifluoroethyl) 2-diazomalonate. The developed protocol is simple and scalable, and has a broad scope and excellent regioselectivity. The pyridyl directing group can easily be removed. The method was further extended to give C-7-functionalized oxindole derivatives in a straightforward manner.
On the Importance of an Acid Additive in the Synthesis of Pyrido[1,2‐
<i>a</i>
]benzimidazoles by Direct Copper‐Catalyzed Amination
作者:Kye‐Simeon Masters、Tom R. M. Rauws、Ashok K. Yadav、Wouter A. Herrebout、Benjamin Van der Veken、Bert U. W. Maes
DOI:10.1002/chem.201100574
日期:2011.5.27
8‐substituted pyrido[1,2‐a]benzimidazoles (4) has been developed by a direct intramolecular CH amination of N‐phenylpyridin‐2‐amines (3). Efficient CH amination of 3 could only be achieved in the presence of catalytic copper and an acid additive. The type of acid (pKa) proved to be crucial for the catalysis. CCl aminations in N‐(2‐chloroaryl)pyridin‐2‐amines allow access to 9‐substituted pyrido[1,2‐a]benzimidazoles