Citric Acid → HCID 19780736, compound

Participants

Reaction Steps

Nitromethane (0.92 ml, 17 mmol) was added dropwise to a stirred solution of potassium t-butoxide (0.84 g, 8.4 mM) in N,N-dimethylformamide (DMF; 40 ml) at -5° C. When the addition was complete, stirring was continued for 30 minutes at -5° C. Sodium 2,3-dimethyl-4-oxo-4H-chromene-6-sulphonate (2.2 g, 8.5 mM) was then added, followed immediately by iodine (1.07 g, 4.2 mM). The mixture was allowed to attain ambient temperature and stirred overnight. The reaction mixture was then added to a solution of citric acid (15 g) and sodium metabisulphite (3 g) in water (150 ml). The aqueous mixture was extracted with dichloromethane (3×50 ml) and the combined organic extracts were washed with sodium chloride solution. The solvent was removed by evaporation and the residual semi-solid purified by flash vacuum chromatography on silica, eluting with ethyl acetate/hexane (1:1 v/v), to give 2,3-dimethyl-6-(nitromethyl-sulphonyl)-4H-chromen-4-one as a solid (178 mg, 7.1% yield), m.p. 206°-209° C. [after recrystallisation from toluene]; NMR (d6DMSO): 2.0(3H,s), 2.45(3H,s), 7.5(2H,s), 7.75(1H,d), 8.1(1H,dd), 8.45(1H,d); microanalysis, found: C,49.0; H,3.6; N,4.7%; C12H11NO6S requires: C,48.5; H,3.6; N,4.7%.

Provenance & Evidence