Reaction #1132

Reaction equation

5-Trimethylsilylethynyl-3-(1-methyl-2-pyrrolidinyl)pyridine

cesium carbonate

→

5-ethynyl-3-(1-methyl-2-pyrrolidinyl)pyridine

Solvents

methanol

Conditions

Workup

1. 1
   Temperatureheated
2. 2
   Temperatureunder reflux for 5 h
3. 3
   TemperatureAfter cooling the solvents
4. 4
   Otherwere removed in vacuo
5. 5
   workup.DISSOLUTIONthe residue dissolved in ethyl acetate (40 mL)
6. 6
   Washwashed with water (10 mL)
7. 7
   ExtractionThe aqueous layer was extracted with ethyl acetate (40 mL)
8. 8
   Washthe combined organic extracts washed with brine (10 mL)
9. 9
   Dryingdried (Na2SO4)
10. 10
    Concentrationconcentrated in vacuo
11. 11
    OtherThe crude product was chromatographed on "flash" silica gel with ethyl acetate:hexane (1:9, 1:4, 1,3)

Procedure

Repeating the procedure of Example 16, but using trimethylsilylacetylene in place of phenylacetylene, 5-ethynyl-3-(1-methyl-2-pyrrolidinyl)pyridine and the fumarate derivative thereof were obtained as follows. 5-Trimethylsilylethynyl-3-(1-methyl-2-pyrrolidinyl)pyridine (516 mg, 2 mmol) and cesium carbonate (200 mg, 0.6 mmol) were dissolved in methanol (10 mL) and heated under reflux for 5 h. After cooling the solvents were removed in vacuo and the residue dissolved in ethyl acetate (40 mL) and washed with water (10 mL). The aqueous layer was extracted with ethyl acetate (40 mL) and the combined organic extracts washed with brine (10 mL), dried (Na2SO4) and concentrated in vacuo. The crude product was chromatographed on "flash" silica gel with ethyl acetate:hexane (1:9, 1:4, 1,3) to afford 5-ethynyl-3-(1-methyl-2-pyrrolidinyl)pyridine as an oil, 218 mg, 59%.

Source