22348-44-3

111300-06-2

22348-44-3

The general procedure for the synthesis of trans-4-methylaminocyclohexanol from trans-4-BOC-aminocyclohexanol was as follows: lithium aluminum hydride (9 g, 0.23 mol) was suspended in dry tetrahydrofuran (425 mL) under argon protection. Trans-4-(tert-butoxycarbonylamino)cyclohexanol (Intermediate 1, 10 g, 0.046 mol) was slowly added under cooling in an ice bath. After addition, the ice bath was withdrawn and the reaction mixture was heated to reflux and kept at reflux overnight. Upon completion of the reaction, the mixture was cooled to room temperature, followed by careful sequential dropwise addition of 9 mL of water, 9 mL of 4N NaOH solution and 18 mL of water under stirring to quench the reaction. The organic solvent was removed by distillation under reduced pressure and the resulting crude product was dissolved in chloroform and dried with anhydrous magnesium sulfate. After filtration, the filtrate was concentrated to dryness under reduced pressure and finally co-evaporated with hexane to afford trans-4-methylaminocyclohexanol as a white solid in 89% yield. The structure of this intermediate was confirmed by 1H NMR (300 MHz, chloroform-d), δppm 1.04-1.20 (m, 2H), 1.25-1.40 (m, 2H), 1.97 (br.s., 4H), 2.27-2.40 (m, 1H), 3.57-3.70 (m, 1H).