Propionic Acid → Ethyl 3-(2-chloroethyl)-3-methylpent-4-enoate

Participants

Reaction Steps

To a solution of 1.97 parts of a 2:1 mixture of E/Z stereoisomers of 5-chloro-3-methyl-2-penten-1-ol in 20 parts by volume of triethyl orthoacetate is added 0.14 part of propionic acid. This solution is heated for 40 hours in an oil bath (~150°) in such a manner that the ethanol that forms during the reaction is slowly distilled through a Vigreaux column. After cooling the solution, 20 parts by volume of pentane and 20 parts by volume of 1 M sulfuric acid are added, and this mixture is stirred vigorously for 5 minutes to hydrolyze the excess triethyl orthoacetate. The mixture is then diluted with 150 parts by volume of water and the product is isolated by pentane extraction. The pentane extracts are washed with saturated sodium bicarbonate, 10% sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. Removal of the pentane, followed by fractional distillation, yields 2.27 parts (76%) of ethyl 3-[2-chloroethyl]-3-methyl- 4-pentenoate. The formula is: ##STR2##

Provenance & Evidence