Reaktion #42340

Reaktionsgleichung

n-butyllithium

1-tert-butyldimethylsilylimidazole

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

→

title compound

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

Lösungsmittel

ethyl acetate

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture is heated
2. 2
   Temperaturat reflux for 15 h
3. 3
   Waschenwashed with water, and brine
4. 4
   Trocknendried (sodium sulfate)
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated under reduced pressure
7. 7
   SonstigePurification by flash column chromatography (silica gel, 1-5% methanol/methylene chloride)

Vorschrift

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).

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