Hydrochloric Acid → (S)-(6-bromo-2-methyl-3,4-dihydroquinoxalin-1 (2H)-yl)(cyclopropyl)methanone

Temperatur

50 °C

A 200-mL round bottomed flask fitted with a nitrogen inlet, magnetic stir bar, and condenser was charged with (S)-tert-butyl 7-bromo-4-(cyclopropanecarbonyl)-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate (5.74 g, 14.52 mmol), ethanol (100 mL), water (25 mL), and 6 M hydrochloric acid solution (2.66 mL, 15.97 mmol). The reaction mixture was heated to 50° C. for 24 h and then cooled to room temperature. The ethanol was removed under reduced pressure, the residue was extracted into dichloromethane (100 mL), and the extract was concentrated under reduced pressure. The crude material was purified by column chromatography on silica gel (eluting with 3:2 hexanes-ethyl acetate) to afford (S)-(6-bromo-2-methyl-3,4-dihydroquinoxaline-1(2H)-yl)(cyclopropyl)methanone (4.00 g, 93%) as an off-white solid. MS (ESI, pos. ion) m/z 295, 297 [M+1]+.

1. customA 200-mL round bottomed flask fitted with a nitrogen inlet, magnetic stir bar, and condenser
2. temperaturecooled to room temperature
3. customThe ethanol was removed under reduced pressure
4. extractionthe residue was extracted into dichloromethane (100 mL)
5. concentrationthe extract was concentrated under reduced pressure
6. customThe crude material was purified by column chromatography on silica gel (eluting with 3:2 hexanes-ethyl acetate)

ORD-Eintrag

ord-93c051a16e5f49ac8b912683d74f4bfd

Quelldatensatz

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09422281B2