Efficient Synthesis of Benzidronate Applying of Phosphorus Trichloride and Phosphorous Acid
David Illes Nagy,
The optimized synthesis of benzidronate involves the reaction of phenylacetic acid with 3 equivalents of
phosphorus trichloride and 1 equivalent of phosphorous acid in methanesulfonic acid at 85 °C followed by hydrolysis, pH
adjustment and purifications. The positive effect of phosphorous acid on the yield is a novel observation and is probably
limited to this model. The heap of our experimental data obtained by varying the molar equivalent quantities of the
P-reagents (PCl3 and P(OH)3) and reacting also phenylacetic chloride and ethyl phenylacetate allowed us to draw
conclusions on the possible intermediates.
Keywords: Benzidronate, intermediates, optimization, phosphorous acid, phosphorus trichloride.
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