Oxidant-Mediated Nitrogenation and Recyclization of Imidazo[1,2-a ]pyridines with Sodium Azide: Synthesis of 4H -Pyrido[1,2-a ][1,3,5]triazin-4-ones

Rh(III)-Catalyzed Imidoyl C-H Carbamylation and Cyclization to Bicyclic [1,3,5]Triazinones

A Rh(III)-catalyzed synthesis of bicyclic [1,3,5]triazinones from a diverse array of imines coupled with ethyl (pivaloyloxy)carbamate is reported. The preparation of [5,6]- and [6,6]-bicyclic heterocycles substituted with aryl, alkyl, and alkoxy groups demonstrated a broad reaction scope. The efficiency of this approach was further enhanced with the development of a three-component variant featuring in situ imine formation. X-ray crystallographic characterization of a rhodacycle formed by imidoyl C-H activation provides support for the proposed mechanism.

Oxidative sulfonamidomethylation of imidazopyridines utilizing methanol as the main C1 source

An efficient one pot, three component synthesis of C3 sulfonamidomethylated imidazopyridines has been disclosed under metal-free conditions, which utilized the commercially available and renewable reagent methanol as the main methylene source. A wide range of substituted imidazopyridines and sulfamides/amines were well tolerated to afford the corresponding products in up to 92% yield. In the isotopic labelling experiment, it was found that a minor part of the methylene also originated from DTBP. Moreover, the radical scavenger reactions were conducted, which suggested that a free-radical mechanism was probably not involved. The current methodology featured several advantages, including broad substrate scope, good functional group tolerance and high reaction efficiency.

Efficient synthesis of 2-arylquinazolin-4-amines via a copper-catalyzed diazidation and ring expansion cascade of 2-arylindoles

Copper-catalyzed synthesis of 2-arylquinazolin-4-amines from readily available 2-arylindoles and TMSN₃ has been developed.