Reaktion #1135

Reaktionsgleichung

pyridine

trifluoroacetic acid

→

5-(4-fluorophenyl)-3-(2-piperidinyl)pyridine

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe solvents were removed in vacuo
2. 2
   workup.DISSOLUTIONthe crude material dissolved in ethyl acetate (50 mL)
3. 3
   workup.ADDITIONSaturated sodium carbonate solution (30 mL) was added
4. 4
   Sonstigethe organic layer separated
5. 5
   ExtraktionThe aqueous phase was extracted with two further portions of ethyl acetate (2×30 mL)
6. 6
   Waschenthe combined organic extracts washed with brine (20 mL)
7. 7
   Trocknendried (Na2SO4)
8. 8
   Einengenconcentrated in vacuo
9. 9
   SonstigeThe residue was chromatographed on silica gel with ethyl acetate

Vorschrift

The above-described pyridine derivative (1.25 g, 3.5 mmol) was dissolved in a mixture of dichloromethane (10 mL) and trifluoroacetic acid (10 mL) and this was stirred at 25° C. for 18 h. The solvents were removed in vacuo and the crude material dissolved in ethyl acetate (50 mL). Saturated sodium carbonate solution (30 mL) was added and the organic layer separated. The aqueous phase was extracted with two further portions of ethyl acetate (2×30 mL), the combined organic extracts washed with brine (20 mL), dried (Na2SO4) and concentrated in vacuo. The residue was chromatographed on silica gel with ethyl acetate, then methanol:ethyl acetate (1:9) as eluant to afford 5-(4-fluorophenyl)-3-(2-piperidinyl)pyridine, 940 mg, 100%. NMR (CDCl3, 300 MHz): δ 8.69 (d, J=2 Hz, 1 H), 8.55 (d, J=2 Hz, 1 H), 7.93 (t, J=2 Hz, 1 H), 7.56 (m, 2 H), 7.16 (app. tm, J=9 Hz, 2 H), 3.18 (d, J=12 Hz, 1 H), 2.83 (td, J=12, 3 Hz, 1 H), 2.61 (bs exch., 1 H), 1.92 (m, 2 H), 1.45-1.75 (m, 6 H).

Quelle