3-Methyl-2-buten-1-OL → Methyl 3,3-dimethyl-4-pentenoate

Participants

Reaction Conditions

Reaction Steps

A mixture of trimethyl orthoacetate (120 g; 1 mole) and orthophosphoric acid (1.5 g; 0.015 mole) was placed in a flask equipped with a stirrer and a vacuum-jacketed fractionating column and the mixture was heated, with stirring to a temperature of 110° C. 3-Methylbut-2-enol (21.5 g; 0.25 mole) was added dropwise to the hot reaction mixture over a period of 1 hour during which time the methanol formed was collected by distillation. On completion of the addition the reaction mixture was heated at a temperature of 110° C. for a further period of 1 hour with collection of methanol by distillation. Portion (72 g; 0.6 mole) of the excess trimethyl orthoacetate was then distilled from the reaction mixture, the distillation being continued until the reaction mixture reached a temperature of 140°-145° C. The reaction mixture was then heated to a temperature of 140°-145° C. for a period of 1.5 hours, the remaining excess trimethyl orthoacetate being allowed to condense and return to the reaction mixture. The product was then distilled to separate the remaining excess trimethyl orthoacetate and to give methyl 3,3-dimethylpent-4-enoate (29.4 g; 82.8%), bp 70° C. at 60 mm Hg.

Provenance & Evidence