Supported Palladium‐Catalyzed Tandem Synthesis of 2‐(Alkylamino/amino)‐3‐arylquinazolin‐4(3H)‐ones Employing CO Source

An efficient tandem addition and intramolecular aminocarbonylative cyclization has been developed for the synthesis of various 2-(benzyl/alkylamino)-3-arylquinazolin-4(3H)-one derivatives. This approach has been successfully extended for the synthesis of 2-amino-3-phenylquinazolin-4(3H)-one derivatives under ammonia and CO surrogate conditions.

Abstract

Herein, we demonstrated heterogeneous and recyclable polystyrene-supported palladium (Pd@PS) nanoparticles (NPs) catalyzed tandem addition and intramolecular aminocarbonylative cyclization approach for the synthesis of potentially bioactive 2-(alkylamino/amino)-3-arylquinazolin-4(3H)-one analogues from 2-iodophenylcarbodiimides employing amines as nucleophiles and oxalic acid as an ex-situ CO alternative. Various cyclic/acyclic primary and secondary amines were employed and selectively produced substituted 2-(alkylamino)-3-arylquinazolin-4(3H)-ones in good to excellent yields. In addition, we extended the developed strategy to fix two ammonium carbamate and oxalic acid as gaseous NH₃ and CO sources respectively, for the synthesis of 2-amino-3-arylquinazolin-4(3H)-one derivatives. Furthermore, gram scale applicability, diverse substrate scope and high recyclability of the Pd@PS catalyst were the major achievements of the developed protocol.

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