Synthesis and Antibacterial Activity of Certain Fused Azoles and Oxazinones

Abstract

ALWEDI, E. F.; FAWZY, N. M.; J. Heterocycl. Chem. 49 (2012) 3, 664-668, http://dx.doi.org/10.1002/jhet.777 ; Dep. Chem., Fac. Sci., Sohag Univ., Sohag, Egypt; Eng.) -A. Forchert 48-124

Synthesis of 2‐Alkenyl‐4H‐3,1‐Benzoxazin‐4‐Ones through HFIP‐Mediated Decarboxylative [4+2]‐Annulation of Isatoic Anhydrides with Cyclopropenones under Silver Catalysis

“…On the basis of the preliminary experimental results and the previous literature reports, [5] a plausible reaction mechanism is presented in Scheme 5. First, isatoic anhydride 1 a underwent decarboxylative esterification with HFIP to generate intermediate A under basic conditions.…”

“…[4] The other route to access to 2-alkenyl-4H-3,1-benzoxazin-4-ones was recently achieved from N- (2-carboxyphenyl)-and N-(2-formylphenyl)acrylamides through the intramolecular cyclization strategy (Scheme 1b). [5] Despite the progress, the availability of substrates and required reaction conditions (e. g. CO atmosphere, external oxidant, strong acidic or basic medium, microwave) makes these synthetic methods of limited utility to some extent. Based on our ongoing interest in versatile nitrogencontaining heterocyclic constructions, [6] we herein wish to present an intermolecular synthesis of 2-alkenylsubstituted 4H-3,1-benzoxazin-4-ones from easily available isatoic anhydrides and cyclopropenones.…”