The general procedure for the synthesis of 1-((4'-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)methyl)piperazine-1-carboxylic acid tert-butyl ester as 1-((4'-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)methyl)piperazine was carried out as follows: at 0 °C, 4 M hydrochloric acid of an ethyl acetate solution (4 mL) was slowly added to a dichloromethane solution (15 mL) of compound 19 (0.6 g, 1.44 mmol). The reaction mixture was continued to be stirred at room temperature for 3 hours. Upon completion of the reaction, the reaction mixture was filtered, the filter cake was dissolved with water and neutralized with potassium phosphate. Subsequently, extraction was carried out with ethyl acetate (30 mL x 2). The organic phases were combined and dried with anhydrous sodium sulfate. Finally, the solvent was removed under reduced pressure to give 0.4 g of the target product in 87% yield.
![tert-butyl 4-((4'-chloro-5,5-diMethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)Methyl)piperazine-1-carboxylate](/CAS/20150408/GIF/1228780-71-9.gif)
![1-((4'-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)methyl)piperazine](/CAS/GIF/1228780-72-0.gif)