Silver‐Mediated Synthesis of 4H‐Benzoxazin‐4‐ones by Intramolecular Decarboxylative O‐Acylation Reactions with α‐Oxocarboxylic Acid

Abstract

The first example of an intramolecular decarboxylative acylation reaction for the synthesis of 4H‐benzoxazin‐4‐one derivatives has been described. The silver‐mediated reaction has a broad substrate scope and provides a mild and rapid approach to the corresponding products in high yields.

Thermo-Promoted Reactions of Anthranils with Carboxylic Acids, Amines, Phenols, and Malononitrile under Catalyst-Free Conditions

“…HRMS (ESI) m / z [M + H] + calcd for C 12 H 8 NO 2 S 230.0276, found 230.0274. The characterization data is consistent with reported literature …”

Radical‐Induced, Palladium‐Catalyzed C–H Activation: An Approach to Functionalize 4H‐Benzo[d][1,3]oxazin‐4‐one Derivatives by Using Toluenes, Aldehydes, and Benzyl Alcohols

“…We began our study by examining the reaction between commercially available and easily prepared 2‐phenyl‐4 H ‐benzo[ d ][1,3]oxazin‐4‐one ( 1a , 0.5 mmol) and toluene ( 2a , 2 mL, 15 mmol) in the presence of 3 mol‐% of Pd(OAc) 2 and 70 % aqueous tert ‐butyl hydroperoxide (TBHP) solution (6 mmol) as the radical initiator and oxidant in 1,2‐dichloroethane (DCE, 0.5 mL). The reaction mixture was stirred at 80 °C for 18 h to afford product 3a in 32 % yield along with the highly valuable hydrolyzed product 4a (28 % yield, Table , Entry 1). The formation of 3a encouraged us to optimize the reaction conditions to furnish a better product yield.…”

Recyclable Heterogeneous Palladium-Catalyzed Cyclocarbonylation of 2-Iodoanilines with Acyl Chlorides in the Biomass-Derived Solvent 2-Methyltetrahydrofuran

“…In order to improve the yield and reduce the cost of the reaction, other notable synthetic pathways have also been reported for the synthesis of 4 H -3,1-benzoxazin-4-ones. These methods include copper-catalyzed reactions such as cyclization of N -acyl- o -iodobenzamides, oxidative cyclization of N -TFA-protected 2-alkynylanilines or o -iodobenzoic acids with benzyl amines, oxidation of 2-arylindoles, aza-Wittig reaction of 2-azido phenyl anhydrides, palladium-catalyzed carbon–carbon triple bond cleavage of 2-azidoalkynylbenzenes, and CoCl 2 or Ag 2 O-mediated intramolecular oxidative cyclization . Besides, transition-metal-free syntheses of 4 H -3,1-benzoxazin-4-ones have also been developed through the oxidation of 2-arylindoles with oxone as the sole oxidant or oxidative cyclization of 2-aminobenzoic acids with arylaldehydes or 2-aminobenzyl alcohols with aldehydes .…”