Reaktion #2254188

Reaktionsgleichung

ethylcyanoformate

Ethylmagnesium chloride

3-(5-bromo-4-methyl-thiophen-2-yl)-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole

→

5-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophene-2-carboxylic acid ethyl ester

Ausbeute 56.8%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 40 minutes
2. 2
   Sonstigethe reaction is quenched with a saturated aqueous solution of NH4Cl in water
3. 3
   ExtraktionThe mixture is extracted three times with MTBE
4. 4
   Trocknendried over Na2SO4
5. 5
   Einengenconcentrated in vacuo
6. 6
   SonstigeThe crude product is purified on a semi-preparative HPLC

Vorschrift

Ethylmagnesium chloride (10.9 ml, 2M in THF) is added over 30 minutes to a solution of 3-(5-bromo-4-methyl-thiophen-2-yl)-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole (10.0 g, Example 2, step D) in THF (15 ml) at 0° C. After 1 hour at room temperature, a solution of ethylcyanoformate (2.81 g) in THF (15 ml) is added to the reaction mixture. After 40 minutes, the reaction is quenched with a saturated aqueous solution of NH4Cl in water. The mixture is extracted three times with MTBE. The organic phases are combined, dried over Na2SO4 and concentrated in vacuo. The crude product is purified on a semi-preparative HPLC to yield 5-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophene-2-carboxylic acid ethyl ester (5.6 g) as a yellowish oil.

Quelle