Bromine → 1H-​Indole-​6-​carboxylic acid, 2-​bromo-​3-​cyclopentyl-​1-​methyl-​, 1-​methylethyl ester

Participants

Reaction Steps

This process identified the optimal conditions for the synthesis of 2-bromo-3-cyclopentyl-1-methyl-1H-indole-6-carboxylate via bromination of the corresponding 3-cyclopentyl-1-methyl-1H-indole-6-carboxylate with bromine. It's very important to control the reaction temperature and to quench the reaction mixture with a mixture of aqueous sodium thiosulfate and 4-methylmorpholine to minimize the formation of the dibromo- and 2-indolone impurities. Further neutralization of the crude product with NaOH in isopropanol greatly increases the stability of the isolated product.

Provenance & Evidence