Réaction #217012

Équation de réaction

2-picolyl chloride hydrochloride

5-(2-pyridinyl)pyrazole-3-carboxylic acid ethyl ester

dimethylformamide

sodium hydride

→

1-(1-(2-pyridinyl)ethyl)-3-(2-pyridinyl)pyrazole-5-carboxylic acid ethyl ester

Solvants

water

Conditions de réaction

Traitement

1. 1
   Extractionextracted with ethyl acetate (2×300 ml)
2. 2
   SéchageThe organic solution was dried over sodium sulfate
3. 3
   AutreThe residue was chromatographed (silica gel, EtOAc)

Mode opératoire

To a stirred mixture of 5-(2-pyridinyl)pyrazole-3-carboxylic acid ethyl ester (4.34 g) and anhydrous dimethylformamide (40 ml) at room temperature, 1.92 g of 60% sodium hydride oil suspension were added. After the bubbling had stopped, 3.60 g of 2-picolyl chloride hydrochloride were added. The resulting mixture was stirred at 50° C. overnight, poured into 300 ml of water and extracted with ethyl acetate (2×300 ml). The organic solution was dried over sodium sulfate and rotavaped. The residue was chromatographed (silica gel, EtOAc)to afford 1.93 g of 1-(1-(2-pyridinyl)ethyl)-3-(2-pyridinyl)pyrazole-5-carboxylic acid ethyl ester, as a viscous oil. NMR: 1.31 (t, 3H), 4.29 (q, 2H), 6.00 (s, 2H, 1-pyrazolyl CH2), 7.59 (s, 1H, 4-pyrazolyl H), 6.85, 7.16, 7.32. 7.81, 7.99, 8.57, 8.65 (8 m, 8H, pyridinyl H's). The column also yielded 0.58 g of 1-(1-(2-pyridinyl)ethyl)-5-(2-pyridinyl)pyrazole-3-carboxylic acid ethyl ester, as a viscous oil. NMR: 1.42 (t, 3H), 4.45 (q, 2H), 6.20 (s, 2H, 1-pyrazolyl CH2), 7.26 (s, 1H, 4-pyrazolyl H), 6.74, 7.09, 7.19, 7.51, 7.61, 7.72, 8.49, 8.53 (8 m, 8H, pyridinyl H's).

Source