State-of-the-art and prospects of studying Ritter-type reactions in the synthesis of N-(het)arylamides and N-benzylamides: from the traditional approach to photo- and electrochemistry

N-(Het)aryl- and N-benzylamides are a practically relevant class of compounds that are widely used in medicinal chemistry, agrochemistry, catalysis, organic synthesis and materials chemistry. The amide group is one of the important structural moieties that form the basis of proteins, peptides, pharmaceuticals, polymeric functional materials, etc. To this day, the Ritter reaction, discovered in 1948, is often used in chemical synthesis to obtain amides, especially sterically crowded ones. Nitriles can act as a source of the amide function in the synthesis of N-(het)aryl- and N-benzylamides. The study of such transformations, which are carried out both under conditions of classical organic synthesis and using photochemistry, electrochemistry and photoelectrochemistry, is a relevant area of research, as evidenced by modern works on this topic. This review summarizes and analyzes the most significant achievements of recent years in the field of synthesis of N-(het)aryl- and N-benzylamides by reactions following the Ritter reaction pathway. Processes based on traditional methods of organic chemistry are presented, as well as modern of "green" chemistry approaches using photo- and electrochemical activation of reagents. In addition, known reactions of amidation of heteroaromatic substrates with nitriles, methods of amidation using three-component systems, and amidation of N-(hydroxymethyl)saccharin are considered in separate Sections. Proposed mechanisms of transformations that ensure the selectivity of the processes are discussed in detail.
The bibliography includes 122 references.