Metal-free direct annulation of 2-aminophenols and 2-aminothiophenols with unactivated amides through transamidation: Access to polysubstituted benzoxazole and benzothiazole derivatives
作者:Vishal Kumar、Sanjeev Dhawan、Renu Bala、Pankaj Sanjay Girase、Parvesh Singh、Rajshekhar Karpoormath
DOI:10.1016/j.tet.2022.132794
日期:2022.6
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
我们在此报告了一种简单而新颖的氧化剂、金属和无溶剂绿色方案,用于从 2-氨基苯酚盐酸盐非活化酰胺作为原位碳源合成不同的 2-取代的 1,3-苯并恶唑和苯并噻唑。此外,盐酸盐的氢离子在亲核攻击后的酰胺活化中起关键作用,亲核攻击通过消除胺作为副产物,脱水解步骤导致最终的环化。这种通用策略适用于多种不同取代的邻氨基苯酚、未活化的脂肪族和芳香族酰胺,只需一步即可以良好至极好的收率生产相应的产品。