Pyridine → HCID 57699908, compound

To a slurry of N-bromo succinimide (3.54 g, 19.9 mmol) in DCM (30 ml) was added a solution of triphenyl phosphine (4.87 g, 18.8 mmol) in DCM (15 ml). The solution was stirred for a further 5 minutes before addition of pyridine (644 μl, 7.96 mmol) and a solution of (S)-2-tert-Butoxycarbonylamino-5-hydroxy-pentanoic acid cyclopentyl ester (2.0 g, 6.64 mmol) in DCM (20 ml). The solution was stirred for 18 hrs, concentrated in vacuo and the residual solvent azeotroped with toluene (3×30 ml). The residue was triturated with diethyl ether (30 ml) and ethyl acetate:heptane (1:9, 2×30 ml). The combined ether and ethyl acetate/heptane solutions was concentrated onto silica and purified by column chromatography using ethyl acetate/heptane (1:9-2:8) to provide 1.34 g (55% yield) of title compound as a clear oil. 1H NMR (300 MHz, CDCl3), δ 5.25 (1 H, m), 5.05 (1H, bd), 3.45 (2H, m), 2.00-1.55 (12H, bm), 1.45 (9H, s).

1. concentrationconcentrated in vacuo
2. customthe residual solvent azeotroped with toluene (3×30 ml)
3. customThe residue was triturated with diethyl ether (30 ml) and ethyl acetate:heptane (1:9, 2×30 ml)
4. concentrationThe combined ether and ethyl acetate/heptane solutions was concentrated onto silica
5. custompurified by column chromatography

ORD record

ord-09277e9cbaef43fda54ba2f9622b4082

Source dataset

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07973181B2