Réaction #7249

Équation de réaction

3-cyano-2-chloro-pyridine

methylboronic acid

K2CO3

→

desired product

Rendement 46.1%

3-cyano-2-picoline

Rendement 46.1%

Solvants

dioxane

CH2Cl2

Conditions de réaction

Traitement

1. 1
   Températureat reflux over the weekend
2. 2
   Filtrationfiltered through Celite
3. 3
   Lavagewashing the cake with CH2Cl2 and MeOH
4. 4
   ConcentrationThe filtrate was concentrated in vacuo
5. 5
   Autrepurified by column chromatography on silica gel (Hexanes/ethyl acetate, 9:1

Mode opératoire

To a mixture of 3-cyano-2-chloro-pyridine (422 mg, 3.05 mmol), methylboronic acid (209 mg, 3.49 mmol) and K2CO3 (1.22 g, 8.83 mmol) in degassed dioxane (5 mL) under argon was added Pd(PPh3)4 (222 mg, 0.19 mmol) and the mixture stirred at reflux over the weekend. The reaction was cooled to room temperature, diluted with CH2Cl2 (20 mL) and filtered through Celite, washing the cake with CH2Cl2 and MeOH. The filtrate was concentrated in vacuo and purified by column chromatography on silica gel (Hexanes/ethyl acetate, 9:1 then 4:1) to afford the desired product (166 mg, 46%) as a white solid. 1H NMR (CDCl3): δ 2.78 (s, 3H), 7.25 (dd, 1H, J=9, 6 Hz), 7.90 (dd, 1H, J=6, 3 Hz), 8.69 (d, 1H, J=3 Hz).

Source