Chloroform → Trichloroethyl alpha-amino-diethylphosphonoacetate

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Reaction Steps

A mixture of 2,4-dinitrophenyl hydrazine (1.875 g., 9.47 mMol) and p-toluenesulfonic acid monohydrate (1.800 g., 9.47 mMol) in ethanol (200 ml.) is stirred at room temperature for 45 minutes. To the resulting orange suspension is added trichloroethyl N-benzylidene-α-amino-diethylphosphonoacetate (3.881 g., 9.02 mMol) in a small volume of chloroform. The mixture is stirred for 30 minutes at room temperature, then filtered to remove benzaldehyde 2,4-dinitrophenyl hydrazone. The filtrate is evaporated in vacuo to an orange oil which is taken up in water (50 ml.) and washed with chloroform (4 × 25 ml.) to remove the remainder of the hydrazone. The aqueous phase (pH 2) is cooled in ice, adjusted to pH 10 with 2 N NaOH, saturated with NaCl, and extracted with methylene chloride (2 × 25 ml). The combined extracts are dried over MgSO4 and evaporated in vacuo to give trichloroethyl α-amino-diethylphosphonoacetate as a pale yellow liquid.

Provenance & Evidence