4-(4-Bromopyrazol-1-yl)piperidine-1-carboxylic acid tert-butyl ester

2075-45-8

141699-59-4

877399-50-3

General procedure for the synthesis of tert-butyl 4-(4-bromopyrazol-1-yl)piperidine-1-carboxylate from 4-bromopyrazole and tert-butyl 4-((methylsulfonyl)oxy)piperidine-1-carboxylate: 2.08 kg of cesium carbonate and 0.78 kg of 4-bromopyrazole were dissolved in 4 liters of N-methyl pyrrolidinone, and heated to 80°C. Subsequently, 2.08 kg of cesium carbonate and 0.78 kg of 4-bromopyrazole were dissolved in 5 liters of N-methyl pyrrolidinone. 1.8 kg of tert-butyl 4-((methylsulfonyl)oxy)piperidine-1-carboxylate was added to the reaction mixture and the reaction lasted for 12 hours. After completion of the reaction, it was cooled to room temperature, 50 liters of methyl tert-butyl ether and 50 liters of water were added and stirred for 1 hour. After separating the organic phase, the organic phase was washed 4 times with 20 liters of water, then dried with 50% hexane and stirred for 2 hours at room temperature. Finally, it was filtered and dried to give 1.35 kg of tert-butyl 4-(4-bromopyrazol-1-yl)piperidine-1-carboxylate in 77% yield.