5382-16-1

67-64-1

5570-78-5

The general procedure for the synthesis of 1-isopropyl-4-piperidinol from 4-hydroxypiperidine and acetone was as follows: a mixture of 4-hydroxypiperidine (10 g, 0.10 mol), acetone (21.8 mL, 0.30 mol), acetic acid (5.7 mL, 0.10 mol), and tetrahydrofuran (150 mL) was stirred in an ice bath for 15 minutes. Subsequently, sodium triacetoxyborohydride (31.3 g, 0.15 mol) was added in batches and stirring was continued for 10 minutes. The reaction mixture was gradually warmed up to room temperature, stirred for 10 minutes and then stirred at 40°C for 2.5 hours. After the reaction was completed, the solvent was removed by evaporation under reduced pressure and the residue was dissolved in water (50 mL). The pH of the aqueous solution was adjusted to 9 with concentrated ammonia (0.88) and stirred continuously for 30 minutes. Next, the reaction mixture was extracted with ether (2 x 200 mL), the organic phases were combined, dried with anhydrous sodium sulfate and concentrated in vacuum to obtain a yellow oil. The oily substance was purified by silica gel column chromatography with the eluent ratio of dichloromethane: methanol: concentrated ammonia (0.88), which was tapered from 96:4:1 to 90:10:1, to give the title compound 1-isopropyl-4-piperidinol as a yellow oily substance in a yield quantified as 14.6 g. The product was purified by 1H-NMR (CDCl3, 400 MHz) and mass spectrometry (MS ES+ m/ z 144 [MH]+) to confirm the structure.