RaMelteon iMpurity synthesis

Yield:1204581-51-0 93%

Reaction Conditions:

with bromine;sodium acetate in methanol; for 1.5 h;Cooling with ice;

Steps:

1

Bromine was added dropwise into a solution of (S)-N-(2-[1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl]ethyl)propionamide (27.4 g, 0.1 1 mol) and sodium acetate ( 10.4 g, 0.13 mol) in methanol (200 mL) with ice-cooling. The mixture was allowed to stir for 1.5 hours with ice-cooling, which was quenched with sodium hydrogen sulfite and poured into water, followed by extracting with ethyl acetate. The extracted solution was washed with water and a saturated aqueous solution of sodium hydrogencarbonate. which was dried over anhydrous magnesium sulfate, followed by distilling off the solvent under reduced pressure. The residue was purified by means of silica gel column chromatography (ethyl acetate : hexane = 8:2) to afford the title compound (yield 33.1 g, 93%) as a white powder. m.p.: 129-131 ^"C (recry stall ized from ethyl acetate / hexane)

References:

WO2010/8746,2010,A1 Location in patent:Page/Page column 17