Malic Acid → Dipentyl 2-hydroxybutanedioate

Participants

Reaction Conditions

Reaction Steps

Dipentyl-DL-malate was prepared using a procedure similar to that in Example 4. To the reaction flask, DL-malic acid (100.43 g), 1-pentanol (325 mL) and Amberlyst®15 ion exchange resin (14.2 g) were added. The mixture was placed under nitrogen and heated to reflux. At 108° C., two phases started to collect in the Dean-Stark trap. The reaction was maintained at 110-120° C. for 4 hr 15 min and water was continuously removed. The product was separated from the catalyst via filtration over silica using 300 mL diethyl ether. The organic layer was washed 4 times with saturated sodium bicarbonate, washed once with water, and dried over magnesium sulfate. Diethyl ether was removed via rotary evaporation. Dipentyl-DL-malate was obtained as a low viscosity, slightly hazy, very light yellow liquid with a slight pleasant odor (116.5 g, 55.6% yield) after pumping on the sample in vacuo to remove residual 1-pentanol.

Provenance & Evidence