Aerobic α,β-C(sp<sup>3</sup>)–H Bond Difunctionalization and C–N Bond Cleavage of Triethylamine: Difunctional Ammonium Iodide Enabling the Regioselective Synthesis of 4-Arylpyrimido[1,2-<i>b</i>]indazoles
作者:Qinghe Gao、Xinya Han、Peiyuan Tong、Zhiang Zhang、Haotian Shen、Yanrong Guo、Suping Bai
DOI:10.1021/acs.orglett.9b02218
日期:2019.8.2
A novel method for the regioselective synthesis of 4-arylpyrimido[1,2-b]indazoles has been developed via the dual C(sp3)–H bond functionalization and C–N bond cleavage of triethylamine. The elusive acyclic enamine intermediates are effectively in situ generated and captured by aromatic aldehydes to form a wide array of tricyclic products from 3-aminoindazoles under the NH4I-mediated aerobic oxidative
通过三乙胺的双C(sp 3)-H键官能化和C-N键裂解,开发了一种新的区域选择性合成4-芳基嘧啶[1,2- b ]吲唑的新方法。难以捉摸的无环烯胺中间体可在NH 4 I介导的需氧氧化条件下有效地原位生成并被芳族醛捕获,从而形成多种由3-氨基吲唑形成的三环产物。该反应具有容易获得的原料,绿色和经济条件以及有价值的产品的特点。
Regioselectivity in the Reaction of 2‐Aminobenzothiazoles and 2‐Aminobenzimidazoles with Enaminonitriles and Enaminones: Synthesis of Functionally Substituted Pyrimido[2,1‐<i>b</i>][1,3]benzothiazole and Pyrimido[1,2‐<i>a</i>]benzimidazole Derivatives
作者:Abdulaziz Alnajjar、Mervat Mohammed Abdelkhalik、Hossam Mohammed Riad、Samia Mohammed Sayed、Kamal Usef Sadek
DOI:10.1002/jhet.3337
日期:2018.12
A variety of new polyfunctionally substituted benzo[d]pyrimido[2,1‐b][1,3]thiazole and benzo[4,5]imidazo[1,2‐a]pyrimidine derivatives have been synthesized. The general synthetic procedure used for this purpose involves the condensation of 2‐aminobenzothiazole and 2‐aminobenzimidazole with a variety of enaminonitriles, enaminones, and acrylaldehyde. The regioselectivity for initial attack of either
各种新的多官能取代的苯并[ d ]嘧啶基[2,1– b ] [1,3]噻唑和苯并[4,5]咪唑[1,2- a ]已经合成了]嘧啶衍生物。用于该目的的一般合成方法涉及2-氨基苯并噻唑和2-氨基苯并咪唑与各种烯氨基腈,烯胺和丙烯醛的缩合。研究并合理化了对环内环氮或环外氨基的初始进攻的区域选择性。可以得出结论,环氮是酸性介质中反应性最强的分子,也可以分离出环状中间体,这证明了环化后的结论。然而,在碱性或中性介质中,发现环外氨基是反应性最高的中心。尽可能通过元素分析,光谱数据和替代合成路线阐明了新合成化合物的所有结构。
Synthesis of Structurally Related Purines: Benzimidazo[1,2-a]pyridines, Benzimidazo-[1,2-c]pyrimidines, and Pyrazolo-[1,5-a]pyrimidines
作者:Galal H. Elgemeie、Nadia H. Metwally
DOI:10.1007/s007060050025
日期:——
alkanones with 2-cyanomethylbenzimidazole afforded benzimidazo[1,2- a ]pyridines. Analogues reactions with 2-aminobenzimidazole and 5-aminopyrazoles afforded benzimidazo[1,2- c ]pyrimidines and pyrazolo[1,5- a ]pyrimidines.