Triphenylphosphine → (+)-Ethyl 2-ethoxy-3-[4-[2-[4-oxo-3,4-dihydro-1,3-benzoxazin-3-yl]ethoxy]phenyl]propanoate

Participants

Reaction Steps

To a stirred mixture of 3-(2-hydroxyethyl)-4-oxo-3,4-dihydro-1,3-benzoxazine (325 mg, 1.68 mmol) and triphenylphosphine (660 mg, 2.52 mmol) in toluene (10 mL) was added a solution of (+)-ethyl 2-ethoxy-3-(4-hydroxyphenyl)propanoate (400 mg, 1.68 mmol) at 25° C. and stirred for 10 min. To the reaction mixture was added diisopropyldiazodicarboxylate (0.5 mL, 2.52 mmol) at 25-30° C. and stirred for further 40 h. Water was added to the reaction mixture and extracted with ethyl acetate (3×10 mL). The combined organic extracts were washed with brine, dried over anhydrous Na2SO4 and concentrated. The residue was chromatographed on silica gel using a gradient of 5-15% ethyl acetate in pet ether as eluent to afford the title compound (527 mg, 76%): mp 76-78° C.

Provenance & Evidence