Lithium hydroxide, monohydrate → (5R)-1-{(2S)-2-((tert-butoxycarbonyl)amino)-2-cyclopentylethanoyl}-5-ethynyl-L-proline

To a stirred solution of methyl(5R)-1-{(2S)-2-((tert-butoxycarbonyl)amino)-2-cyclopentylethanoyl}-5-((trimethylsilyl)ethynyl)-L-prolinate (1.65 g, 3.66 mmol) in MeOH (10 mL) and H2O (10 mL) at room temperature was added LiOH.H2O (0.23 g, 5.49 mmol). The reaction mixture was stirred at room temperature for 16 hours and concentrated under reduced pressure. The residue was taken up in water and extracted with diethyl ether (2×). The aqueous layer was acidified to pH˜4 by adding 4% KHSO4 dropwise. The clear solution was extracted with ethyl acetate (3×) and the combined ethyl acetate layers were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure to provide the titled compound. MS (CI) m/e 365 (M+H)+.

1. concentrationconcentrated under reduced pressure
2. extractionextracted with diethyl ether (2×)
3. additionby adding 4% KHSO4 dropwise
4. extractionThe clear solution was extracted with ethyl acetate (3×)
5. washthe combined ethyl acetate layers were washed with brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure

ORD record

ord-cc1c385833814da59d01bd390332113c

Source dataset

uspto-grants-2007_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07262207B2