Clofibric Acid → Fibric acid

To a solution of 20.0 g (0.93 mole) of 2-(4-chlorophenoxy)-2-methylpropionic acid (97%, clofibric acid, Aldrich) in 130 ml of methanol and 50 ml of dioxane was added a solution of 13.9 g (0.244 mole) of potassium hydroxide in 75 ml of water. To this solution were added 5 teaspoonfuls of Raney Nickel (Aldrich) and the mixture was hydrogenated at ambient temperature for 3.25 hr (H2 -uptake ceased). The reaction mixture was filtered through Celite® and the filtrate was concentrated under reduced pressure to a volume of 150 ml. This solution was extracted with 200 ml of ethyl ether and the ether was discarded. The aqueous layer pH was adjusted to 2 with concentrated hydrochloric acid solution and the resulting white solid was collected by filtration and dried to give 16 g (99%) of white solid. An analytical sample was prepared by recrystallizing from cyclohexane-petroleum ether (b.p. range 30°-60° C.) to give white crystals, mp 98°-100° C.

1. filtrationThe reaction mixture was filtered through Celite®
2. concentrationthe filtrate was concentrated under reduced pressure to a volume of 150 ml
3. extractionThis solution was extracted with 200 ml of ethyl ether
4. filtrationthe resulting white solid was collected by filtration
5. customdried

ORD record

ord-b70d0fb132884df6ac5ea9b62b7ae345

Source dataset

uspto-grants-1993_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05273993