Arnold, Eric P.; Mondal, Prolay K.; Schmitt, Daniel C. published an article on January 13 ,2020. The article was titled 《Oxidative Cyclization Approach to Benzimidazole Libraries》, and you may find the article in ACS Combinatorial Science.Reference of 4-Amino-2-picoline The information in the text is summarized as follows:
An efficient approach to the parallel synthesis of benzimidazoles from anilines is described. Library approaches to vary the N1 and C2 vectors of benzimidazoles are well established; however, C4-C7 variation has traditionally relied on 1,2-dianiline building blocks, providing limited chem. space coverage. We have developed an amidine formation/oxidative cyclization sequence that enables anilines as a diversity set for benzimidazole C4-C7 SAR generation in parallel format. The amidine annulation was achieved using PIDA or Cu-mediated oxidation to access both N-H and N-alkyl benzimidazoles. This library protocol has now been utilized for analog production in four medicinal chem. projects. Addnl., the synthesis of aza-benzimidazoles from aminopyridines was achieved via an analogous sequence. After reading the article, we found that the author used 4-Amino-2-picoline(cas: 18437-58-6Reference of 4-Amino-2-picoline)
4-Amino-2-picoline(cas: 18437-58-6) belongs to anime. Reaction with nitrous acid (HNO2), which functions as an acylating agent that is a source of the nitrosyl group (―NO), converts aliphatic primary amines to nitrogen and mixtures of alkenes and alcohols corresponding to the alkyl group in a complex process. This reaction has been used for analytical determination of primary amino groups in a procedure known as the Van Slyke method.Reference of 4-Amino-2-picoline