Valproic Acid → Magnesium;bis(2-propylpentanoate);hydrate

Participants

Reaction Steps

A solution of magnesium valproate in absolute ethanol was obtained in the following manner. To a magnetically stirred, clear, colorless solution of valproic acid (3.17 g; 0.022 mol; Sigma Aldrich Chemical Co.) in 25 mL of absolute ethanol was added 1.14 g (0.01 mol) of magnesium ethoxide solid; residual solid was rinsed in with 1 mL of absolute ethanol. Within 60 minutes, a clear, pale yellow solution was obtained; no heating was observed. One milliliter portions of the solution were aliquoted into test tubes, and a second solvent or solution was added in portions. The results of the additions are summarized in Table 2. A 15 mL portion of acetonitrile was added to an equal volume of the ethanol solution of magnesium valproate. A white precipitate formed, which was isolated by filtration, washed with a fresh portion of acetonitrile, and dried to constant mass. The product, magnesium valproate hydrate, was obtained in 89% yield as a white solid, which exhibited an elemental composition identical to that calculated for magnesium valproate hydrate. The product did not melt at temperatures as high as 300° C. The product was not hygroscopic or deliquescent. The theoretical valproate content (weight %) of magnesium valproate hydrate is 88.6%; the valproate content found by HPLC analysis was 88.5%.

Provenance & Evidence