Benzyl chloroformate → 1-Benzyloxycarbonylamino-2-phenylethylphosphonous acid

Participants

Reaction Conditions

Reaction Steps

2.25 ml (14.25 mmol) of benzyl chloroformate are added dropwise, at 0° C. and within the space of 30 min., to a suspension of 1.76 g (9.5 mmol) of 1-amino-2-phenylethylphosponous acid in 15 ml of 1M NaOH, 5 ml of water and 5 ml of dioxane. During a further 2.5 h of stirring at 0° C., the pH of the mixture is maintained at 9-10 using 1M NaOH (approximately 10 ml). After removing the cooling medium, the mixture is stirred at RT overnight. The reaction solution is then washed several times with diethyl ether. The aqueous phase is adjusted to pH 2, at 0°-5° C., using 6M HCl and extracted several times with ethyl acetate. The combined extracts are washed with a saturated solution of NaCl, dried with Na2SO4, filtered and subjected to rotary evaporation i.V. A solid residue remains which is recrystallized from ether/petroleum ether.

Provenance & Evidence