N,1-二芳基-1 H-四唑-5-胺的N-芳基环的Pd(II)催化邻位选择性卤化已通过N-卤代琥珀酰亚胺通过CH键进行卤素活化。目前的工作以5-氨基四唑为导向基团,用于芳烃的化学和区域选择性CH卤代。动力学同位素研究(k H / k D = 2.9)表明,CH键的裂解发生在速率确定步骤中。该协议的范围和机制已得到证明。
Palladium catalyzed carbonylative annulation of the C(sp<sup>2</sup>)–H bond of <i>N</i>,1-diaryl-1<i>H</i>-tetrazol-5-amines and <i>N</i>,4-diaryl-4<i>H</i>-triazol-3-amines to quinazolinones
as both directing as well as intramolecular nucleophiles. The catalytically active C–H activated intermediate dimeric Pd complex was isolated and characterized which on exposure to CO gas gave the corresponding tetrazole fused quinazolinone derivative. On the basis of isolation of the intermediate and observed kinetic isotope effects, a mechanism has been proposed for the C–H activated direct carbonylative
Desulfurization Strategy in the Construction of Azoles Possessing Additional Nitrogen, Oxygen or Sulfur using a Copper(I) Catalyst
作者:Srimanta Guin、Saroj Kumar Rout、Anupal Gogoi、Shyamapada Nandi、Krishna Kanta Ghara、Bhisma K. Patel
DOI:10.1002/adsc.201200408
日期:2012.10.8
A tandem and convergent approach to various N-, O-, or S-containing azoles has been developed by exploiting the thiophilic property of copper(I) iodide used in a catalytic quantity. The present protocol gives access to amino-substituted tetrazoles, triazoles, oxadiazoles and thiadiazoles via oxidative desulfurization of their respective precursors followed by inter- or intramolecular attack of suitable
compatibility. The procedure features the use of operationally simple protocol utilizing the commercially available less toxic CuCl2·2H2O as catalyst and Fe(NO3)3·9H2O as nitration source at room temperature. Removal of the 5-aminotetrazole directing group has been demonstrated using base hydrolysis to afford substituted 2-nitroanilines.
5-aminotetrazoles has been developed by employing simple ketones as substrates. This methodology involved the N2-extrusion/aryl migration of azido complexes as the key step for the in situ generation of carbodiimidium ion, which could further react with hydrazoic acid and cyclize intramolecularly to provide 5-aminotetrazoles in good to excellent yields. In addition, the regioselectivity of the reaction was studied