Réaction #1135

Équation de réaction

pyridine

trifluoroacetic acid

→

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

Solvants

dichloromethane

Conditions de réaction

Traitement

1. 1
   AutreThe 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
   Autrethe organic layer separated
5. 5
   ExtractionThe aqueous phase was extracted with two further portions of ethyl acetate (2×30 mL)
6. 6
   Lavagethe combined organic extracts washed with brine (20 mL)
7. 7
   Séchagedried (Na2SO4)
8. 8
   Concentrationconcentrated in vacuo
9. 9
   AutreThe residue was chromatographed on silica gel with ethyl acetate

Mode opératoire

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).

Source