Metal-free direct annulation of 2-aminophenols and 2-aminothiophenols with unactivated amides through transamidation: Access to polysubstituted benzoxazole and benzothiazole derivatives

被引：18

作者：

Kumar, Vishal ^{[1
]}

Dhawan, Sanjeev ^{[1
]}

Bala, Renu ^{[1
]}

Girase, Pankaj Sanjay ^{[1
]}

Singh, Parvesh ^{[2
]}

Karpoormath, Rajshekhar ^{[1
]}

机构：

[1] Univ KwaZulu Natal Westville, Coll Hlth Sci, Dept Pharmaceut Chem, Discipline Pharmaceut Sci, ZA-4000 Durban, South Africa

[2] Univ KwaZulu Natal, Sch Chem & Phys, Westville Campus,Private Bag X01, Durban, South Africa

来源：

TETRAHEDRON | 2022年 / 115卷

基金：

新加坡国家研究基金会;

关键词：

Amine; Amide; Annulation; Transamidation; BOND FORMATION; OXAZOLE; ARYLATION; CHEMISTRY;

D O I：

10.1016/j.tet.2022.132794

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

We herein report a simple yet novel oxidant, metal and solvent-free green protocol for synthesising differently 2-substituted 1,3-benzoxazoles and benzothiazoles from 2-aminophenol hydrochloride salt unactivated amide as in situ carbon source. Further, the hydrogen ion of hydrochloride played a crucial role in amide activation followed nucleophilic attack that through eliminations of amine as a side product, and de-hydrolysis step leads to final annulation. This versatile strategy is applicable to a wide variety of differently substituted o-aminophenols, unactivated aliphatic and aromatic amides, yielding the corresponding product in good to excellent yields in a single step. (C) 2022 Published by Elsevier Ltd.

引用

页数：9