Sulfuric Acid → (4S)-4-cyclohexyl-L-proline

To a solution of Jones reagent (2 ml) was added sulfuric acid (0.5 ml) and acetic acid (2.5 ml). (2S-trans)-4-Cyclohexyl-2-pyrrolidinemethanol (0.5 g) in 5 ml of acetic acid was added to the above solution and after the addition, it was stirred at room temperature for 15 minutes. The reaction mixture was filtered through a Celite pad and washed with 10 ml of acetic acid. Isopropyl alcohol (2 ml) was added to the filtrate, stirred well, and a clear solution decanted and concentrated to a thick oil. The oil was dissolved in 5 ml of water and the pH was brought to 6.0 by the addition of concentrated ammonium hydroxide. The resultant precipitate was filtered, washed with 5 ml of water and excess ether, and vacuum dried to yield 0.42 g of (trans)-4-cyclohexyl-L-proline as a pink solid, which was crystallized from methanol to obtain colorless crystals.

1. additionafter the addition, it
2. filtrationThe reaction mixture was filtered through a Celite pad
3. washwashed with 10 ml of acetic acid
4. additionIsopropyl alcohol (2 ml) was added to the filtrate
5. stirringstirred well
6. customa clear solution decanted
7. concentrationconcentrated to a thick oil
8. dissolutionThe oil was dissolved in 5 ml of water
9. additionthe pH was brought to 6.0 by the addition of concentrated ammonium hydroxide
10. filtrationThe resultant precipitate was filtered
11. washwashed with 5 ml of water and excess ether, and vacuum
12. customdried

ORD record

ord-fb1b469744e141d18fb6e417dbd3dd1f

Source dataset

uspto-grants-1986_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04625038