Lithium tri-s-butylborohydride → HCID 59278476, compound

To a chilled (−78° C.) solution of 2-methyl-propane-2-sulfinic acid [(S)-1-(4-bromopyridin-2-yl)-propyl]-amide (985 mg, 3.10 mmol) in THF (25 mL) is added a 1 M solution of L-Selectride (3.2 mL, 3.2 mmol) in THF. The reaction is monitored by TLC (EtOAc-ether 3:7) indicating a single diastereomer when compared to a mixture of diastereomers prepared by reduction of 2-methyl-propane-2-sulfinic acid [(S)-1-(4-bromopyridin-2-yl)-propyl]-amide with lithium borohydride in THF. After 3 hours, the mixture is quenched with saturated aqueous ammonium chloride (30 mL) and extracted with EtOAc (3×25 mL). The combined organic layers are washed with brine (3×30 mL), dried over magnesium sulfate, filtered and concentrated. The crude material is purified by silica gel chromatography eluting with a gradient of 0-100% EtOAc in dichloromethane. The material from the column is crystallized from hexanes to afford (S)-1-(4-bromopyridin-2-yl)-propylamine.

1. additioncompared to a mixture of diastereomers
2. customthe mixture is quenched with saturated aqueous ammonium chloride (30 mL)
3. extractionextracted with EtOAc (3×25 mL)
4. washThe combined organic layers are washed with brine (3×30 mL)
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude material is purified by silica gel chromatography
9. washeluting with a gradient of 0-100% EtOAc in dichloromethane
10. customThe material from the column is crystallized from hexanes

ORD record

ord-7fa71b89766841feb1e99e10744f4411

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08927550B2