Pyridine → HCID 57699908, compound

To a slurry of N-bromo succinimide (3.54 g, 19.9 mmol, 3 eq) in DCM (30 ml) was added a solution of triphenyl phosphine (4.87 g, 18.8 mmol, 2.8 eq) in DCM (15 ml). The solution was stirred for a further 5 minutes before addition of pyridine (644 μl, 7.96 mmol, 1.2 eq) 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 hours, 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 to 2:8) to provide the title compound as a clear oil (1.34 g, 55% yield).

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-eba364da547f47128344deb425813aee

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08217050B2