Sodium Bicarbonate → (S)-tert-butyl 7-bromo-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate

HRID 1485670Notes

Reaction equation

[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([N:6](C(=O)C(F)(F)F)[C@@H:7]([CH3:19])[CH2:8][N:9]2[C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])=[CH:4][CH:3]=1.C(=O)(O)[O-].[Na+]>C(O)C>[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([NH:6][C@@H:7]([CH3:19])[CH2:8][N:9]2[C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 70 °C

Procedure

A 500-mL round bottomed flask fitted with a nitrogen inlet, magnetic stir bar, and condenser was charged with (S)-tert-butyl 7-bromo-3-methyl-4-(2,2,2-trifluoroacetyl)-3,4-dihydroquinoxaline-1(2H)-carboxylate (13.10 g, 31.0 mmol), ethanol (130 mL), and half-saturated aqueous sodium bicarbonate solution (130 mL, 31.0 mmol). The reaction mixture was heated to 70° C. for 24 h and then cooled to room temperature. The ethanol was removed under reduced pressure, and the residue was extracted into dichloromethane (250 mL). The combined organic layers were concentrated under reduced pressure. The crude product was purified by column chromatography on silica gel (eluting with 4:1 hexanes-ethyl acetate) to afford (S)-tert-butyl 7-bromo-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate (9.78 g, 97%) as a white solid. MS (ESI, pos. ion) m/z 327, 329 [M+1]+.

Workup

customA 500-mL round bottomed flask fitted with a nitrogen inlet, magnetic stir bar, and condenser
temperaturecooled to room temperature
customThe ethanol was removed under reduced pressure
extractionthe residue was extracted into dichloromethane (250 mL)
concentrationThe combined organic layers were concentrated under reduced pressure
customThe crude product was purified by column chromatography on silica gel (eluting with 4:1 hexanes-ethyl acetate)

Sources & evidence

ORD record: ord-d924ca3a0a8649909e47ce8df7220132
Source dataset: uspto-grants-2016_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09422281B2

Reaction notes

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