Borane;tetrahydrofuran → (R)-2-bromo-1-pyridin-3-yl-ethanol

Temperature

0 °C

A solution of borane-THF (1 M solution, 15 mL) was added dropwise to a 0° C., stirred solution of (S)-2-methyl-CBS-oxazaborolidine monohydrate (0.738 g, 2.5 mmol) in THF (10 mL) over a period of 10 min. After stirred at 0° C. for 10 minutes the mixture was then added dropwise into a cold (0° C.) stirred suspension of 3-(2-bromoacetyl)pyridine hydrobromide (7.0 g, 24.9 mmol) in THF (50 mL) over a period of 10 minutes. After addition was completed the mixture was stirred at room temperature under a nitrogen atmosphere overnight. The reaction was cooled to 0° C. and quenched with dry HCl (0.5 M in methanol, 9 mL) The mixture was further diluted with water and extracted with ethyl acetate. The extract was washed with water and dried with MgSO4. Evaporation and purification by flash column chromatography (methylene chloride/methanol 95/5) gave (1 R)-2-bromo-1-(3-pyridinyl)-1-ethanol as a brown oil (1.72 g, 34%). This solid (1.71 g, 8.5 mmol) was dissolved in THF (15 mL) and 5 N aqueous sodium hydroxide (30 mL) was added. After the solution was stirred at room temperature for 10 minutes, the mixture was diluted with water and extracted with methylene chloride. The extract was washed with water, dried with MgSO4, and concentrated to give a white solid (0.72 g, 72%): MS m/z 122 (M+H)+.

1. additionwas then added dropwise into a cold (0° C.)
2. stirringstirred
3. additionAfter addition
4. stirringwas stirred at room temperature under a nitrogen atmosphere overnight
5. temperatureThe reaction was cooled to 0° C.
6. customquenched with dry HCl (0.5 M in methanol, 9 mL) The mixture
7. additionwas further diluted with water
8. extractionextracted with ethyl acetate
9. washThe extract was washed with water
10. dry with materialdried with MgSO4
11. customEvaporation and purification by flash column chromatography (methylene chloride/methanol 95/5)

ORD record

ord-ccf301a1c643457eb5eb077c6e06344a

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06569873B2