Triphenylphosphine → Benzyl 4-[4-(2-tert-butoxycarbonylaminoethoxy)phenyl]-3-[4-(3-methoxypropyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazin-6-ylmethoxy]piperidine-1-carboxylate

Participants

Reaction Steps

A solution of 1.197 g of benzyl 4-(4-hydroxyphenyl)-3-[4-(3-methoxypropyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazin-6-ylmethoxy]piperidine-1-carboxylate (Example 166c), 0.506 ml of tert-butyl (2-hydroxyethyl)carbamate and 0.848 g of triphenylphosphine in 10 ml of tetrahydrofuran at 0° C. is admixed dropwise with 0.66 ml of diisopropyl azodicarbonate. The reaction mixture is warmed to room temperature, stirred further for 22 hours and subsequently concentrated by evaporation. The title compound is obtained as a yellow oil from the residue by means of flash chromatography (SiO2 60F). Rf=0.50 (2:1 EtOAc-heptane); Rt=5.39.

Provenance & Evidence