Organocatalytic oxidative synthesis of C2-functionalized benzoxazoles, naphthoxazoles, benzothiazoles and benzimidazoles
作者:Dhananjaya Kaldhi、Nagaraju Vodnala、Raghuram Gujjarappa、Subhashree Nayak、V. Ravichandiran、Sreya Gupta、Chinmoy K. Hazra、Chandi C. Malakar
DOI:10.1016/j.tetlet.2018.12.017
日期:2019.1
give analogous benzoxazoles, naphthoxazoles, benzothiazoles and benzimidazoles. A mechanistic proposal has been drawn based upon the control experiments. It was demonstrated that under the influence of aerobic conditions the catalytic amounts of tBuOOH can be generated by auto-oxidation of tert-butoxide base which plays a decisive role towards successful completion of the developed approach. The described
描述了一种有效的有机催化方法,用于将邻氨基苯酚,1-氨基-2-萘酚,邻氨基苯硫酚和邻苯二胺与醇进行环化,在需氧氧化条件下生成相应的苯并恶唑,萘并恶唑,苯并噻唑和苯并咪唑。该方法依赖于使用3-硝基吡啶作为唯一催化剂在好氧条件下将苄醇或肉桂醇原位转化为相应的醛。开发的协议不包括使用昂贵的金属如Ru,Pd和Cu作为催化剂和刺激性氧化剂。大量取代的邻氨基苯酚,1-氨基-2-萘酚,邻氨基苯硫酚和在优化的反应条件下耐受邻苯二胺,得到类似的苯并恶唑,萘并恶唑,苯并噻唑和苯并咪唑。根据控制实验已提出了机械方案。结果表明,在有氧条件下,叔丁氧基碱的自氧化可产生t BuOOH的催化量,这对成功完成所开发的方法起着决定性的作用。所描述的方法被扩展以产生广泛的衍生物,分离的产率高达96%。