Hydrochloric Acid → Levamisole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 15.65 kg of levamisole.L-N-[(4-methoxyphenyl)sulfonyl]glutamic acid (salt) (30.02 mol) dissolved in 20.3 l water and 3,15 l sodium hydroxide 19.5 molar aqueous solution was extracted with 30.4 l of methylbenzene at 40° C. and the aqueous layer was washed with 7.5 l methylbenzene. Weighing of the combined water layers and determination of the concentration of the di-sodium salt of L-N-[(4-methoxyphenyl)sulfonyl]glutamic acid yields a 97% amount of di-sodium salt of L-N-[(4-methoxyphenyl)sulfonyl]glutamic acid. To the combined water layers were added 25.2 l water and 13.48 kg of tetramisole hydrochloride. After warming up at about 45° C. the aqueous solution was adjusted to pH 4.2 with hydrochloric acid and cooled at 15° C. After 18 hours the precipitate was filtered off, washed and dried under vacuo at 50° C. yielding 14.27 kg of levamisole.L-N-[(4-methoxyphenyl)sulfonyl]glutamic acid (salt) (yield: 97.7%); αD20 =- 64.1 (c5. 1N HCl); mp. 127.8°-129.3° C..

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