Sulfuric Acid → 5-Bromo-3,4-dihydroquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of sodium azide (862 mg, 13.3 mmol) in H2O (1.7 mL) and CHCl3 (6.5 mL) was added conc. H2SO4 (0.23 mL, 4.14 mmol). The reaction mixture was stirred vigorously at 0° C. for 2.5 h. The CHCl3 layer was separated, dried over Na2SO4, and added to a solution of 4-bromo-1-indanone (1.12 g, 5.31 mmol) in CHCl3 (20 mL). To this mixture was added conc. H2SO4 (1.75 mL, 31.5 mmol) dropwise over 10 min. The reaction mixture was heated at 45 C for 1 h then poured into ice-water, neutralized with 20% aqueous NaOH, and extracted with CH2Cl2 (100 mL). The organic extract was dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:EtOAc—100:0 to 80:20, to give the title compound. MS: m/z=226 (M+1).

Provenance & Evidence