Synthesis of 1,3-Disubstituted Imidazo[1,5-a]pyridines from Amino Acids via Catalytic Decarboxylative Intramolecular Cyclization

Abstract

A copper/iodine cocatalyzed decarboxylative cyclization of α-amino acids is described. Starting from the readily available amino acids and either 2-benzoylpyridines or 2-benzoylquinolines, 1,3-disubstituted imidazo[1,5-a]pyridines and 1,3-disubstituted imidazo[1,5-a]quinolines were prepared in excellent yields.

One‐Pot Synthesis of 3‐Sulfenyl/Selenylimidazo[1,5‐a]quinolines from 2‐Methylquinolines, Aliphatic Amines/Amino Acids, and Dichalcogenides

“…Recently, Xu and Wang have developed a method for the synthesis of fused[1,5‐ a ] N ‐heteroaromatics with α‐amino acids via copper/iodine co‐catalyzed decarboxylative cyclization Besides, Wang and Ji group described one‐pot synthesis of 3‐(alkylselanyl)‐2‐arylimidazo[1,2‐ a ]pyridines from pyridin‐2‐amine, arylmethyl ketone and selenosulfonate by employing iodine in catalytic amount for cyclization and selenylation strategy . By considering the above two reports, when we performed the one‐pot multi component reaction of 2‐methylquinolines with phenyl glycines and diphenyl disulfides or diphenyldiselenide under the standard conditions (Table ), afforded the corresponding 3‐ sulfenyl/selenylimidazo[1,5‐ a ]quinolines in moderate to good yields ( 4ca – 4cj ).…”

Synthesis of 1,3‐Disubstituted Imidazo[1,5‐a]pyridines through Oxidative C‐N Bond Formation from Aryl‐2‐pyridylmethanols and Their Fluorescent Study

“…Interestingly, we observed the product 3 a in 88% yield after 14 hours. Involving similar kind of amino acids in the same reaction condition gave rise to the corresponding imidazo[1,5‐ a ]pyridines in good yields through the in situ decarboxylative cyclization ( 3 a , 3 ab and 3 ac ) as shown in Table …”

Recent Advances on Diverse Decarboxylative Reactions of Amino Acids

“…Wang and Xu et al. reported a convenient synthesis of 1,3‐diarylimidazo[1,5‐ a ]pyridines 340 by decarboxylative cyclization of α‐amino acids 164 with 2‐benzoylpyridines 339 in the presence of a copper/iodine catalytic system (Scheme ) . According to the proposed reaction mechanism (Scheme ), the condensation reaction between 2‐benzoylpyridine 341 and an amino acid provided an imine 342 .…”