p-Toluenesulfonic acid → (R)-2-bromo-1-pyridin-3-yl-ethanol

In a round-bottomed flask, bromoacetaldehyde dimethoxyacetal (123 μl, 1.04 mmol), p-toluenesulfonic acid (199 mg, 1.04 mmol), and 4-hydroxy-thiobenzamide (160 mg, 1.04 mmol) were dissolved in ethanol (10 ml) and the resulting solution was heated to reflux for about twenty-four hours. The reaction mixture was then concentrated to an oil which was redissolved in ethyl acetate, and extracted with saturated aqueous sodium carbonate. The combined organic extracts were then washed with brine, dried over magnesium sulfate, filtered, and concentrated in vacuo to an oil. The crude product was purified by column chromatography (hexanes to 10% ethyl acetate/hexanes) to furnish the title compound as a white solid (113 mg, 61% yield). LRMS ([M+H+])=177.8. Preparation of Intermediate 1-(4-Methoxy-phenyl)-1H-pyrazole:

1. temperaturethe resulting solution was heated
2. temperatureto reflux for about twenty-four hours
3. concentrationThe reaction mixture was then concentrated to an oil which
4. dissolutionwas redissolved in ethyl acetate
5. extractionextracted with saturated aqueous sodium carbonate
6. washThe combined organic extracts were then washed with brine
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo to an oil
10. customThe crude product was purified by column chromatography (hexanes to 10% ethyl acetate/hexanes)

ORD record

ord-2688f0c188b94a44945f8a4a8cab2304

Source dataset

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06919460B2