反应详情

A solution of 4-hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylic acid phenylmethyl ester (EXAMPLE 17, Step 1, 2.50 g) in dry methylene chloride under N2 is treated with trifluoroacetic acid (0.84 mL), stirred at ambient temperature for three hours, diluted with saturated aqueous potassium carbonate (25 mL) to neutralize excess trifluoroacetic acid, and the layers are separated. The organic phase is washed with water (20 mL) and saline (20 mL), dried over anhydrous sodium sulfate and concentrated under reduced pressure, and the residue is chromatographed on silica gel (230-400 mesh, 300 g), eluting with a gradient of ethyl acetate/hexane (20/80-50/50). Pooling of fractions with an Rf =0.69 by TLC (ethyl acetate/hexane, 50/50) and removal of solvent under reduced pressure gives the title compound, mp 146-148° C.

1. customthe layers are separated
2. washThe organic phase is washed with water (20 mL) and saline (20 mL)
3. dry with materialdried over anhydrous sodium sulfate
4. concentrationconcentrated under reduced pressure
5. customthe residue is chromatographed on silica gel (230-400 mesh, 300 g)
6. washeluting with a gradient of ethyl acetate/hexane (20/80-50/50)
7. customPooling of fractions with an Rf =0.69 by TLC (ethyl acetate/hexane, 50/50) and removal of solvent under reduced pressure