51395-42-7

Butedronic acid,Bayer A.G.

ChEBI: Butedronic acid is a 1,1-bis(phosphonic acid).

0.5 mole of methylene diphosphonic acid tetraethyl ester is heated for 6 h to 110°C with 0.5 mole of maleic acid diethyl ester in the presence of 25 ml of a saturated sodium ethylate solution. The sodium ethylate is then neutralized with acetic acid and the reaction mixture is quickly distilled invacuo in order to avoid decomposition. The crude distillate is redistillated, the main fraction accumulating in the range from 190-213°C at a pressure of 0.05 Torr, yield 50%.
The ester is hydrolyzed by boiling with concentrated hydrochloric acid. 1,1- Diphosphonopropane-2,3-dicarboxylic acid crystallizes out after purification with active carbon and concentration of the hydrolysis product, yield 100%.

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