Reaktion #72298

Reaktionsgleichung

Potassium carbonate

3-Iodopyridine

Methyl phenylpropiolate

O-(mesitylsulfonyl)hydroxylamine

→

title compound

Ausbeute 12.0%

Methyl 6-iodo-2-phenylpyrazolo[1,5-a]pyridine-3-carboxylate

Ausbeute 12.0%

Lösungsmittel

diethyl ether

Dichloromethane

dimethylformamide

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeequipped with a magnetic stir bar
2. 2
   TemperaturThis colorless solution was cooled on an ice bath
3. 3
   Sonstigethe solvent was removed by rotory evaporation
4. 4
   Sonstigeto give a white solid
5. 5
   SonstigeReaction slowly turned dark green
6. 6
   workup.STIRRINGAfter stirring at room temp for 2 hours
7. 7
   Extraktionextracted 8×25 mL water
8. 8
   SonstigeThe solvent was removed from the organic portion by rotory evaporation
9. 9
   workup.DISSOLUTIONThe crude product was dissolved in a minimum amount of dichloromethane
10. 10
    workup.ADDITIONcharged to a 90 g “Single Sep” silica gel cartridge
11. 11
    Wascheneluted with 0 to 40% ethyl acetate in hexanes over 1000 mL

Vorschrift

Dichloromethane (10 mL) and 3-Iodopyridine (928 mg, 4.53 mmol) were charged to a 100 mL round-bottomed flask equipped with a magnetic stir bar. This colorless solution was cooled on an ice bath and O-(mesitylsulfonyl)hydroxylamine (975 mg, 4.53 mmol) in dichloromethane (10 mL) was added dropwise over 5 minutes. After to stirring at room temperature for 30 minutes, the solvent was removed by rotory evaporation to give a white solid. Methyl phenylpropiolate (1000 mg, 6.24 mmol) was added in dimethylformamide (9 mL). Potassium carbonate (2504 mg, 18.12 mmol) was added. Reaction slowly turned dark green. After stirring at room temp for 2 hours, the reaction was poured into diethyl ether (300 mL and extracted 8×25 mL water. The solvent was removed from the organic portion by rotory evaporation. The crude product was dissolved in a minimum amount of dichloromethane and charged to a 90 g “Single Sep” silica gel cartridge and eluted with 0 to 40% ethyl acetate in hexanes over 1000 mL. The title compound (200 mg, 12%) was isolated as an orange solid. 1H NMR (500 MHz, CHLOROFORM-D) δ ppm 3.83 (s, 3H) 7.46 (m, 3H) 7.59 (dd, J=9.16, 1.53 Hz, 1H) 7.75 (m, 2H) 8.00 (dd, J=9.31, 0.76 Hz, 1H) 8.82 (s, 1H). LCMS: 2.4 minutes, M+1=379.

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