Pyridine → HCID 57699869, compound

To a slurry of N-bromo succinimide (1.86 g, 10.4 mmol) in DCM (16.2 ml) was added a solution of triphenyl phosphine (2.56 g, 9.74 mmol) in DCM (7.2 ml). The solution was stirred for a further 5 minutes after addition. Pyridine (338 μl, 4.18 mmol) was added, followed by a solution of (S)-2-tert-butoxycarbonylamino-4-hydroxy-butyric acid cyclopentyl ester (1.0 g, 3.48 mmol) in DCM (8.8 ml). The solution was stirred for 18 hrs, concentrated in vacuo and the residual solvent azeotroped with toluene (3×16 ml). The residue was triturated with diethyl ether (10 ml) and ethyl acetate:heptane (1:9, 2×10 ml). The combined ether and heptane solutions was concentrated onto silica and purified by column chromatography using ethyl acetate/heptane (1:9-2:8) to provide 1.02 g (84% yield) of title compound. 1H NMR (300 MHz, CDCl3), δ: 5.30-5.05 (2 H, m), 4.45-4.30 (1H, m), 3.45 (2H, t, J=7.3 Hz), 2.50-2.30 (1H, m), 2.25-2.10 (1H, m), 1.95-1.60 (8H, b m), 1.47 (9H, s).

1. additionafter addition
2. stirringThe solution was stirred for 18 hrs
3. concentrationconcentrated in vacuo
4. customthe residual solvent azeotroped with toluene (3×16 ml)
5. customThe residue was triturated with diethyl ether (10 ml) and ethyl acetate:heptane (1:9, 2×10 ml)
6. concentrationThe combined ether and heptane solutions was concentrated onto silica
7. custompurified by column chromatography

ORD record

ord-c2d1a31fd1754ad3813f4d1f987edeaa

Source dataset

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07973181B2