Borane;tetrahydrofuran → 1-Cyclopropyl-1,2,3,4-tetrahydroquinoxaline

Participants

Reaction Steps

To a stirred suspension of 1-cyclopropyl-1,4-dihydro-quinoxaline-2,3-dione (10.0 g, 49.45 mmol, 1.0 equiv) in THF (500 mL) was added dropwise a 1 M solution of borane-tetrahydrofurane complex (108.8 mL, 108.8 mmol, 2.2 equiv; [CAS RN 14044-65-6]) and the reaction mixture stirred at rt over night. The solvent was removed by evaporation under reduced pressure and the crude reaction mixture extracted from a sat. solution of NaHCO3 (100 mL) with ethyl acetate (3×100 mL). The combined organic phases were dried over Na2SO4 and purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane/ethyl acetate to give 4.2 g (49%) of the title compound as a light yellow solid. MS (ISP): 175.4 [M+H]+.

Provenance & Evidence