Dimethylformamide → 5-Bromo-3-pyridinecarboxaldehyde

Temperature

0 °C

n-Butylmagnesium chloride (4.00 mmol) in 2.00M tetrahydrofuran solution (2.00 mL) was added to ice-cooled n-butyllithium (8.06 mmol) in 1.55M hexane (5.20 mL). The mixture was stirred at 0° C. for 15 minutes to give a suspension. The suspension was added to a mixture of toluene (15 mL) and tetrahydrofuran (10 mL) containing 2,5-dibromo-pyridine (2.37 g, 10.0 mmol) over a period of 10 minutes or more while keeping the temperature below 5° C. to give an orange solution. The solution was stirred at 0° C. for one hour, and N,N-dimethylformamide (1.0 mL, 13 mmol) was added thereto. The resultant suspension was stirred at room temperature for 30 minutes, and tetrahydrofuran (10 mL) was added, followed by further stirring at room temperature for 30 minutes. After addition of 1M aqueous acetic acid (20 mL) to the suspension, the organic phase was separated, and the aqueous phase was extracted with toluene (20 mL). The organic phase and the toluene extract were combined, washed with an aqueous sodium chloride saturated solution (15 mL), dried over magnesium sulfate and concentrated under reduced pressure to remove the solvent. The resultant residue was purified by flash column chromatography on silica gel in a developing solvent system of hexane-ethyl acetate (10:1, v/v) to give the title compound (1.062 g, 57% yield) as a colorless solid.

1. customto give a suspension
2. customthe temperature below 5° C.
3. customto give an orange solution
4. stirringThe solution was stirred at 0° C. for one hour
5. stirringby further stirring at room temperature for 30 minutes
6. customthe organic phase was separated
7. extractionthe aqueous phase was extracted with toluene (20 mL)
8. extractionThe organic phase and the toluene extract
9. washwashed with an aqueous sodium chloride saturated solution (15 mL)
10. dry with materialdried over magnesium sulfate
11. concentrationconcentrated under reduced pressure
12. customto remove the solvent
13. customThe resultant residue was purified by flash column chromatography on silica gel in a developing solvent system of hexane-ethyl acetate (10:1

ORD record

ord-0f9b9e8d19ff4dbc969331c52cd4d5fb

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07439535B2