Reaktion #638981

Reaktionsgleichung

3,4-dihydro-1(2H)-quinoxalinecarbamic acid

diisopropylethylamine

dichloromethane

sodium hydrogencarbonate

triphosgene

diisopropylethylamine

3-(pyrrolidin-3-yl)pyridine

→

tert-butyl 4-[(3-(pyridin-3-yl)pyrrolidin-1-yl)carbonyl]-3,4-dihydroquinoxaline-1(2H)-carboxylate

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITthe reaction mixture is left
2. 2
   workup.STIRRINGthe reaction mixture is stirred for eighteen hours
3. 3
   Extraktionthe aqueous phase is extracted three times with dichloromethane
4. 4
   Trocknendried over sodium sulfate
5. 5
   Sonstigethe solvent is evaporated under reduced pressure
6. 6
   SonstigeThe residue is chromatographed on silica gel with a dichloromethane/methanol 95/5 mixture

Vorschrift

2.75 g of the tert-butyl ester of 3,4-dihydro-1(2H)-quinoxalinecarbamic acid, 117 ml of dichloromethane and 5.8 ml of diisopropylethylamine are placed in a 500 ml round-bottomed flask under a nitrogen atmosphere. 1.74 g of triphosgene are added at 0° C. and then the reaction mixture is left stirring at ambient temperature for three hours. 2 ml of diisopropylethylamine and 1.83 g of 3-(pyrrolidin-3-yl)pyridine are subsequently added and the reaction mixture is stirred for eighteen hours. 200 ml of a saturated aqueous sodium hydrogencarbonate solution are added and then the aqueous phase is extracted three times with dichloromethane. The organic phases are combined and dried over sodium sulfate and the solvent is evaporated under reduced pressure. The residue is chromatographed on silica gel with a dichloromethane/methanol 95/5 mixture. 3.72 g of tert-butyl 4-[(3-(pyridin-3-yl)pyrrolidin-1-yl)carbonyl]-3,4-dihydroquinoxaline-1(2H)-carboxylate are obtained.

Quelle