Hydrochloric Acid → beta-Cyclododecenyl-beta-tert-butoxycarbonyl propionic acid

Participants

Reaction Steps

20.06 Grams (0.418 mole) of 50% sodium hydride dispersion was introduced into a 1 liter four-necked flask equipped with a thermometer, a tap funnel, a reflux cooler and a stirrer and washed with benzene. Then 500 ml of pure tetrahydrofuran and 20 ml of t-BuOH were added thereto and the mixture was refluxed for 30 mins. During the reflux, there was dropwise added 150 ml of pure tetrahydrofuran containing dissolved therein 61.87 g (0.340 mol) of cyclododecanone and 86.0 g (0.374 mol) of di-tert-butyl succinate, over 1.5 hour. After that the reflux was continued to complete the reaction. After the reaction, a mixture of 100 ml of water and 78 ml of concentrated hydrochloric acid was added to the reaction product and the obtained mixture was concentrated. The solvent was removed and the product mixture was twice extracted with 250 ml of ether. The extract liquid was washed with water and dried, followed by concentration to obtain 115.1 g of crude β-cyclododecenyl-β-tert-butoxycarbonyl propionic acid II with the purity of 86.8% and the yield of 86.9%. The crude product was found to include about 2% of cyclododecanone and about 5% of high boiling point-having by-products and the balance of the impurities was solvents.

Provenance & Evidence