Phosphoric Acid → Methyl 3,3-dimethyl-4-pentenoate

Participants

Reaction Steps

A mixture of trimethyl orthoacetate (120 g; 1 mole), 3-methylbut-2-enol (21.5 g; 0.25 mole) and orthophosphoric acid (1.5 g; 0.015 mole) was placed in a flask equipped with a stirrer and a 10 cm fractionating column packed with Fenske rings. The mixture was heated, with stirring, to a temperature of 95° to 110° C. and maintained at this temperature for a period of 2 hours while the methanol formed was collected by distillation. The excess trimethyl orthoacetate was distilled from the reaction mixture over a period of 1 hour during which time the temperature of the reaction mixture was raised to 140°-145° C. The reaction mixture was heated with stirring, at a temperature of 140°-145° C. for a period of 1 hour and then product was distilled to give methyl 3,3-dimethylpent-4-enoate (14.4 g; 40.6%); bp 95°-99° C. at 140 mm Hg.

Provenance & Evidence