BF3·OEt2‐Mediated Synthesis of 2‐Arylthio‐ and (N‐Aryl‐2,5‐dioxopyrrolidin‐3‐yl)‐Substituted 1,4‐Benzoxazine Derivatives

Abstract

1,4‐Benzoxazines have been explored as versatile precursors for the synthesis of novel benzoxazine and benzoxazinone derivatives. 2‐Hydroxy‐1,4‐benzoxazines and 1,4‐benzoxazinones have been functionalized with thiols and N‐arylmaleimides, respectively, in the presence of BF3·OEt2 as a promoter. All the products were obtained in moderate to excellent yields. The Michael reactions of the benzoxazinones with maleimides furnished diastereomeric mixtures of adducts, which were characterized by standard spectroscopic methods.