Water → 1-(5-Bromo-3-(tert-butylamino)quinoxalin-2-yl)ethanol

HRID 1056173Notes

Reaction equation

[CH3:1][Mg]Br.[Br:4][C:5]1[CH:14]=[CH:13][CH:12]=[C:11]2[C:6]=1[N:7]=[C:8]([NH:17][C:18]([CH3:21])([CH3:20])[CH3:19])[C:9]([CH:15]=[O:16])=[N:10]2.O>C1COCC1>[Br:4][C:5]1[CH:14]=[CH:13][CH:12]=[C:11]2[C:6]=1[N:7]=[C:8]([NH:17][C:18]([CH3:21])([CH3:20])[CH3:19])[C:9]([CH:15]([OH:16])[CH3:1])=[N:10]2

Participants

Conditions

Temperature: 0 °C

Procedure

Methylmagnesium bromide (Aldrich) (3.0M in Et2O; 2.23 mL, 6.70 mmol) was added to a solution of 5-bromo-3-(tert-butylamino)quinoxaline-2-carbaldehyde (306a) (983.0 mg, 3.19 mmol) in THF (15.0 mL) at 0° C., and the resulting solution was stirred at 0° C. for 5 min. Water (5 mL) was added, and the resulting mixture was partitioned between saturated aq. NaHCO3 (80 mL) and EtOAc (120 mL). The organic layer was separated and sequentially washed with brine (60 mL), dried over Na2SO4, filtered, and concentrated in vacuo. Chromatographic purification of the residue (silica gel, 0-40% EtOAc/hexanes) furnished 1-(5-bromo-3-(tert-butylamino)quinoxalin-2-yl)ethanol (952 mg, 2.94 mmol, 92% yield) as a light-yellow solid (following trituration with hexanes). 1H NMR (400 MHz, CDCl3) δ ppm 7.83 (1H, dd, J=7.6, 1.4 Hz), 7.75 (1H, dd, J=8.2, 1.4 Hz), 7.19 (1H, t, J=7.9 Hz), 5.74 (1H, br. s.), 5.01 (1H, q, J=6.7 Hz), 3.55 (1H, br. s.), 1.63 (9H, s), 1.59 (3H, d, J=6.7 Hz). m/z (EST, +ve) 324.1/326.1 (M+H)+.

Workup

customthe resulting mixture was partitioned between saturated aq. NaHCO3 (80 mL) and EtOAc (120 mL)
customThe organic layer was separated
washsequentially washed with brine (60 mL)
dry with materialdried over Na2SO4
filtrationfiltered
concentrationconcentrated in vacuo
customChromatographic purification of the residue (silica gel, 0-40% EtOAc/hexanes)

Sources & evidence

ORD record: ord-5707dbc34a1e4e15a6df4a3f577ffb75
Source dataset: uspto-grants-2016_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09394297B2

Reaction notes

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