931-03-3Relevant articles and documents
Carboxylation of indoles and pyrroles with CO2 in the presence of dialkylaluminum halides
Nemoto, Koji,Onozawa, Satoru,Egusa, Naoki,Morohashi, Naoya,Hattori, Tetsutaro
experimental part, p. 4512 - 4514 (2009/11/30)
The Lewis acid-mediated carboxylation of arenes with CO2 has been successfully applied to 1-substituted indoles and pyrroles by using dialkylaluminum chlorides instead of aluminum trihalides. Thus, the carboxylation of 1-methylindoles, 1-benzyl-, and 1-phenylpyrroles proceeds regioselectively with the aid of an equimolar amount of Me2AlCl under CO2 pressure (3.0 MPa) at room temperature to afford the corresponding indole-3-carboxylic acids and pyrrole-2-carboxylic acids in 61-85% yields, while the same treatment of 1,2,5-trimethylpyrrole affords the 3-carboxylic acid in 52% yield.