反应详情

1-Cyclopentene-1,2-dicarboxylic acid (10.0 g., 0.064 mole) in 200 ml. of absolute ethanol is hydrogenated (Paar shaker) in the presence of Raney nickel at 40-50 psi/60°. After uptake of one equivalent of hydrogen (~24 hours), the mixture is cooled, filtered through a Celite (diatomaceous earth) pad, and the filtrate concentrated in vacuo to a solid. Direct recrystallization from water (~30 ml.) followed by drying in vacuo over phosphorus pentoxide yields 6 g. (60%) of cis-1,2-cyclopentanecarboxylic acid, m.p. 132°-135°. The mother liquor from the recrystallization can be lyophilized to a solid, which is sufficiently pure for use in the next step.

1. customat 40-50 psi/60°
2. filtrationfiltered through a Celite (diatomaceous earth) pad
3. concentrationthe filtrate concentrated in vacuo to a solid
4. customDirect recrystallization from water (~30 ml.)
5. dry with materialby drying in vacuo over phosphorus pentoxide
6. customyields 6 g
7. customThe mother liquor from the recrystallization