Tetrabutylammonium Fluoride → Benzyl 4-{4-[3-(2,5-difluorophenoxy)propoxy]phenyl}-3-[4-(2-hydroxyethyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazin-6-ylmethoxy]piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

The solution of 2.0 g of benzyl 4-{4-[3-(2,5-difluorophenoxy)propoxy]phenyl}-3-[3-oxo-4-(2-triisopropylsilanyloxyethyl)-3,4-dihydro-2H-benzo[1,4]oxazin-6-ylmethoxy]piperidine-1-carboxylate in 30 ml of tetrahydrofuran is admixed with 2.30 ml of tetrabutylammonium fluoride solution (1M in tetrahydrofuran) and stirred at 60° C. over 30 minutes. The reaction mixture is cooled, poured onto water (100 ml) and extracted with tert-butyl methyl ether (2×100 ml). The organic phases are washed with brine (1×100 ml), dried over sodium sulphate, filtered and concentrated by evaporation. The title compound is obtained as a white foam from the residue by means of flash chromatography (SiO2 60F). Rf=0.10 (1:1 EtOAc-heptane); Rt=5.43.

Provenance & Evidence