Process for preparing R-(-)carnitine from S-(-)-chlorosuccinic acid or from a derivative thereof
AssigneeSigma-Tau Industrie Farmaceutiche Riunite S.p.A.
InventorsPiero Melloni, Alberto Cerri, Marco Santagostino
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Abstract
An inner salt of L-carnitine is prepared by reduction, with a suitable reducing agent, of a compound of formu (I): where X1 and X2, which may be the same or different, are hydroxy, C1-C4 alkoxy, phenoxy, halogen, or X1 and X2, when taken together are an oxygen atom and the resulting compound is a derivative of succinic anhydride; Y is halogen, a mesyloxy or a tosyloxy group, and subsequent treatment with water, then with a base and then with trimethylamine.
Claims7
A process for the preparation of S-(−)-chlorosuccinic acid comprising reacting S-(=)-aspartic acid and sodium nitrite in a hydrochloric acid-aqueous milieu in which said S-(+)-aspartic acid is suspended in demineralized water in a w/w ratio ranging from 1 kg/L to 0.5 kg/L, and concentrated hydrochloric acid is added in a ratio of S-(+)-aspartic acid to hydrochloric acid ranging from 0.35 kg/L to 0.55 kg/L in the presence of sodium chloride, said S-(+)-aspartic acid and said sodium chloride being in a molar ratio ranging from 1:0.3 to 1:0.5, the improvement consisting in isolating by precipitation of the reaction product by cooling the reaction mixture at a temperature ranging from −10° C. to −20° C.
Dependencies are inferred from the claim text.