Dichloromethane → [4-(4-Isobutyryl-piperazine-1-carbonyl)-cyclohexylmethyl]-carbamic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of trans-4-(tert-Butoxycarbonylamino-methyl)-cyclohexanecarboxylic acid (8.5 g, 32.8 mmol) in DCM (100 mL) 1,1-carbonyldiimidazole (4.87 g, 30.1 mmol) was added and the reaction was left stirring for 2 hours. Then isobutyryl-piperazine (6.95 g, 27.3 mmol) was also added and the reaction was left stirring for 16 h at room temperature. The mixture was diluted with 50 mL of H2O, the organic phase collected and the solvent removed under reduced pressure. The residue was washed with 1N NaOH solution and the precipitate was filtered, affording 8.7 g (21.9 mmol) of [4-(4-Isobutyryl-piperazine-1-carbonyl)-cyclohexylmethyl]-carbamic acid tert-butyl ester. The product obtained was dissolved in 100 mL of DCM and H2SO4 (2.92 mL, 54.9 mmol) was added. The reaction was stirred for 18 hours and the mixture was washed with 50 mL of 15% NaOH solution, the organic phase was collected and concentrated under reduced pressure. 3.85 g of the titled product were obtained (yield=48%).

Herkunft & Nachweise