反应详情

To a stirring solution of 5.0 g of 4-(2,3,4,5,6-pentafluorophenoxy)piperidine in 50 ml of methanol was added 15 ml of 37% formaldehyde. After refluxing for 1 hour, the solution was cooled to ice bath temperature, treated (portionwise), with 2.5 g of sodium borohydride, and then stirred at ambient temperature for one hour. Evaporation of the volatiles yielded a residue which was taken up in ethyl acetate, washed with water followed by a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. Concentration afforded an oil which was purified by means of high pressure liquid chromatography (silica gel; elution with 10% methanol/dichloromethane) to yield 4.2 g of 1-methyl-4-(2,3,4,5,6-pentafluorophenoxy)piperidine as an oil. The oil which was dissolved in isopropanol and acidified to pH 1 with etheral hydrogen chloride to precipitate 2.34 g (39%) of the corresponding hydrochloride salt, m.p. 151°-153° C.

1. temperatureAfter refluxing for 1 hour
2. temperaturethe solution was cooled to ice bath temperature
3. customEvaporation of the volatiles
4. customyielded a residue which
5. washwashed with water
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationConcentration
8. customafforded an oil which
9. customwas purified by means of high pressure liquid chromatography (silica gel; elution with 10% methanol/dichloromethane)