(2R)-Oxiran-2-ylmethyl butanoate → (R)-(-)-3,6-Dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2 H)-pyridinecarboxylic acid phenylmethyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester (EXAMPLE 17, Step 2, 0.500 g) in dry tetrahydrofuran (5.7 mL) at -78° C. under N2 is treated with n-butyllithium (0.73 mL, 1.6M in hexanes) dropwise over five minutes. The resulting mixture is stirred at 78° C. for 45 minutes and is then treated with (R)-(-)-glycidyl butyrate dropwise. The resulting solution is allowed to warm to ambient temperature over approximately 45 minutes and is stirred for an additional 20 hours, after which the reaction is quenched with saturated aqueous ammonium chloride (10 mL), diluted with water (20 mL) and extracted with ethyl acetate (2×15 mL). The combined organic phase is washed with saline (10 mL), dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give the crude product which is chromatographed on silica gel (230-400 mesh, 40 g), eluting with methanol/methylene chloride (1/99). Pooling and concentration of those fractions with an Rf =0.37 by TLC (methanol/chloroform, 5/95) gives the title compound, mp 131.5-133.5° C.

Provenance & Evidence