Dibenzoylmethane → (3,3-Dibenzoylpropylidene)bisphosphonic acid tetraethyl ester

Participants

Reaction Steps

Ethenylidenebisphosphonic acid tetraethyl ester (I, 3.00 g), dibenzoyl methane (II, 2.30 g), and DBU (0.25 ml) are heated to 50° in THF (20 ml) for 15 min. The reaction mixture is cooled, diluted with ethyl acetate, filtered through magnesium sulfate and concentrated under reduced pressure. The concentrate is chromatographed eluting with ethyl acetate, ethyl acetate/acetone (1/1). The appropriate fractions are pooled and concentrated to give the title compound, MS (m/e) 524 (M+), 419, 387, 373, 268 and 224; IR (neat) 2982, 1736, 1696, 1674, 1594, 1580, 1448, 1392 and 1253 cm-1 ; NMR (CDCl3) 8.07, 7.58, 7.46, 6.18, 4.17, 2.65 and 1.29 δ.

Provenance & Evidence