Reacción #42340

Ecuación de reacción

n-butyllithium

1-tert-butyldimethylsilylimidazole

methyl 3-[(dipropylamino)carbonyl]-5-iodobenzoate

→

title compound

Methyl 3-[(dipropylamino)carbonyl]-5-(1H-imidazol-2-yl)benzoate

Disolventes

ethyl acetate

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe reaction mixture is heated
2. 2
   Temperaturaat reflux for 15 h
3. 3
   Lavadowashed with water, and brine
4. 4
   Secadodried (sodium sulfate)
5. 5
   Filtraciónfiltered
6. 6
   Concentraciónconcentrated under reduced pressure
7. 7
   OtroPurification by flash column chromatography (silica gel, 1-5% methanol/methylene chloride)

Procedimiento

To a −70° C. stirred solution of 1-tert-butyldimethylsilylimidazole (602 mg, 3.3 mmol) in tetrahydrofuran (10 mL) is added n-butyllithium (1.6 M in hexanes, 2.3 mL, 3.63 mmol). After 30 min, zinc chloride (1 M in diethyl ether, 9.9 mL, 9.9 mmol) is added and the reaction mixture is warmed to 0° C. for 1 h. To this mixture is then added methyl 3-[(dipropylamino)carbonyl]-5-iodobenzoate prepared by the method in Example SP-281, step 2 (1.17 g, 3 mmol) followed by palladium(0)tetrakis(triphenylphosphine) (173 mg, 0.15 mmol). The reaction mixture is heated at reflux for 15 h. The reaction mixture is diluted with ethyl acetate (50 mL), washed with water, and brine, dried (sodium sulfate), filtered, and concentrated under reduced pressure. Purification by flash column chromatography (silica gel, 1-5% methanol/methylene chloride) provides the title compound in pure form. 1H NMR (300 MHz, CDCl3) δ 8.64 (s, 1H), 8.14 (s, 1H), 7.97 (s, 1H), 7.19 (s, 2H), 3.96 (s, 3H), 3.51 (m, 2H), 3.32 (m, 2H), 1.73 (m, 2H), 1.57 (m, 2H), 1.01 (m, 3H), 0.73 (m, 3H).

Fuente