Methane → 1-Hydroxy-3-(piperidin-2-yl)-propane-1,1-diphosphonic acid

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Reaction Steps

1.5 g. 3-(Piperidin-2-yl)-propionic acid hydrochloride (m.p.: 193°-195° C., prepared by hydrogenation of 3-(2-pyridyl)-propionic acid in hydrochloric acid medium in the presence of platinum oxide) and 1.3 g. phosphorous acid are melted together at 80° C. After allowing to cool, 1.4 ml. phosphorus trichloride is added dropwise and further heated for 20 hours to 90° C. After cooling, 20 ml. water are carefully added thereto and heated under reflux for 7 hours. The cooled solution is treated with charcoal, filtered and the filtrate evaporated. After drying, the residue is stirred up several times with acetone, then taken up in water, the solution brought with 2N aqueous sodium hydroxide solution to a pH ≈5 and mixed with methanol. After stirring for some time with ice cooling, the precipitate is filtered off with suction and dried. There is obtained 1.05 g. (37% of theory) of the monosodium salt x 2 mole water; m.p. 270°-274° C.; Mrel : 0.41.

Provenance & Evidence