Catalyst Free Synthesis of 2‐Aryl‐2 H ‐benzo[ b ][1,4]oxazines and 3‐Aryl‐2H ‐benzo[ b ][1,4]thiazin‐2‐ones: An Ultrasonication‐assisted Strategy

An ultrasonication-assisted synthesis of 2-Aryl-2H-benzo[b][1,4]oxazines and 3-aryl-2H-benzo[b][1,4]thiazin-2-ones has been established by reacting phenacyl bromides with 2-aminophenol and 2-aminothiophenol, respectively. This approach fosters flexibility in generating a diverse range of 1,4-benzoxazines and 1,4-benzothiazinones under catalyst-free reaction conditions. Further scope toward the synthesis of rarely occurring bis-benzoxazine adduct has also been explored, which enabled us to propose the reaction mechanism.