Reaction #42478

Reaction equation

methyl 4-butyl-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate

borane dimethylsulfide

→

title compound

Yield 45.8%

Methyl 4-butyl-1,2,3,4-tetrahydroquinoxaline-6-carboxylate

Yield 45.8%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturethe resulting mixture was refluxed for 24 h
2. 2
   Otherquenched with methanol
3. 3
   Otherthe solvent was removed under reduced pressure
4. 4
   OtherPurification by flash column chromatography (silica, 1:1 ethyl acetate/hexanes)

Procedure

To an ice-cold, stirred solution of methyl 4-butyl-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate (840 mg) in tetrahydrofuran (32 mL) was added borane dimethylsulfide complex (3.2 mL, 2.0 M tetrahydrofuran) and the resulting mixture was refluxed for 24 h. The mixture was cooled to room temperature, quenched with methanol, and the solvent was removed under reduced pressure. Purification by flash column chromatography (silica, 1:1 ethyl acetate/hexanes) provided 364 mg of the title compound: 1H NMR (300 MHz, CDCl3) δ 7.27, 7.22, 6.41, 3.84, 3.47-3.45, 3.32-3.23, 1.60-1.58, 1.42-1.37, 0.99-0.94.

Source