Reaktion #42396

Reaktionsgleichung

n-butyllithium

oxazole

3-iodo-5-(methoxycarbonyl)benzoic acid

→

title compound

3-(Methoxycarbonyl)-5-(1,3-oxazol-2-yl)benzoic acid

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture is heated
2. 2
   Temperaturat reflux for 15 h
3. 3
   TemperaturThe reaction mixture is cooled
4. 4
   Filtrationfiltered through diatomaceous earth
5. 5
   workup.ADDITIONdiluted with ethyl acetate (50 mL)
6. 6
   Waschenwashed with water, and brine
7. 7
   Trocknendried (sodium sulfate)
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated under reduced pressure
10. 10
    SonstigePurification by flash column chromatography (silica gel, 5% methanol/methylene chloride)

Vorschrift

To a −70° C. stirred solution of oxazole (432 mg, 6.3 mmol) in tetrahydrofuran (10 mL) is added n-butyllithium (2.5 M in hexanes, 2.75 mL, 6.9 mmol). After 30 min, zinc chloride (1 M in diethyl ether, 18.75 mL, 18.75 mmol) is added and the reaction mixture is warmed to 0° C. for 1 h. To this mixture is added a solution of 3-iodo-5-(methoxycarbonyl)benzoic acid prepared by the method in Example SP-281, step 1 (1.8 g, 6 mmol) in anhydrous tetrahydrofuran (10 mL) followed by palladium(0)tetrakis(triphenylphosphine) (291 mg, 0.25 mmol). The reaction mixture is heated at reflux for 15 h. The reaction mixture is cooled, filtered through diatomaceous earth, 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, 5% methanol/methylene chloride) provides the title compound in pure form. ESI MS m/z 246.1 [M−H]−.

Quelle