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 (31.7 g; 0.22 mol; Sigma Aldrich Chemical Co.) in 200 mL of absolute ethanol was added 11.4 g (0.1 mol) of magnesium ethoxide solid; residual solid was rinsed in with 1 mL of absolute ethanol. Within 30 minutes, a clear, pale yellow solution was obtained; no increase in reaction temperature was observed. Acetonitrile (150 mL) was added to the ethanol solution in portions, and when the addition was complete a white precipitate formed. The reaction mixture was cold to the touch. The slurry was stirred for 15 minutes. The product, magnesium valproate hydrate, was isolated by filtration, washed with fresh acetonitrile, and dried to constant weight. The product, magnesium valproate hydrate, was obtained in 79.8% 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 and was stable during storage under ambient conditions. The theoretical valproate content (weight %) of magnesium valproate hydrate is 88.6%; the valproate content found by HPLC analysis was 88.2%.

Provenance & Evidence