Benzaldehyde → Alpha-benzylaminobenzylphosphonic acid

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Reaction Steps

The imine from benzaldehyde and benzylamine (19.5 g; 0.1 mole) was dissolved in pyridine (9 g) and phosphorous acid (8.2 g; 0.1 mole) was added. The mixture was heated at reflux for 3 hours, cooled, basified and extracted with benzene. The residue was acidified to yield a white solid. Crystallization gave N-benzyl α-amino benzylphosphonic acid mp 233°-4°. Phosphorus nmr of a basified aqueous solution gave a peak at -15.9 ppm (relative to 85% H3PO4) consistent with the assigned structure given in Example 1.

Provenance & Evidence