ethyl N-phenylmethoxycarbamate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of ethyl N-benzyloxycarbamate (7.80 g.) in absolute ethanol (5 ml.) was added dropwise to a solution of sodium ethoxide in absolute ethanol [Na: 920 mg., absolute C2H5OH: 100 ml.] at 70° C. and the mixture was stirred at the same temperature for 30 minutes. To the mixture was added dropwise dibutyl 3-chloropropylphosphonate (10.8 g.), whereafter the reaction mixture was refluxed with stirring for 22 hours. The resultant mixture was cooled to give precipitates, which were filtered off. The filtrate was concentrated under reduced pressure to give a residue. To the residue was added ethyl acetate (100 ml.) and water (50 ml.). The ethyl acetate layer was separated, dried over magnesium sulfate and then concentrated under reduced pressure to give an oily residue (16.6 g.). The residue was subjected to column chromatography on silica gel with an eluent (chloroform). Fractions containing the object compound were collected and concentrated under reduced pressure to give oily dibutyl 3 -(N-benzyloxy-N-ethoxycarbonylamino)propylphosphonate (7.33 g.) whereafter the reaction mixture was refluxed with stirring for 22 hours to give precipitates which were filtered off The filtrate was concentrated under reduced pressure to give a residue The ethyl acetate layer was separated dried over magnesium sulfate concentrated under reduced pressure to give an oily residue (16.6 g.) Fractions containing the object compound were collected concentrated under reduced pressure