Aluminum(III) Chloride → 7-Bromo-4,4,6-trimethyl-3,4-dihydro-1H-quinoline-2-one

Beteiligte Stoffe

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Reaktionsschritte

To a solution of 3-methyl-but-2-enoic acid (3-bromo-4-methyl-phenyl)-amide (70.0 g, 261 mmol, Example d) at 90° C. was added portion wise, under argon, with vigorous stirring aluminum chloride (52.3 g, 391 mmol) over 1.5 hr. The reaction mixture was stirred for 2 hours at 110-120° C. The reaction mixture was cooled to room temperature and ice-water was carefully added. The solution was extracted with dichloromethane and the organic washed with 2N HCl, water, saturated aqueous NaHCO3, water and brine, dried (Mg2SO4), filtered and evaporated. The residue was crystallized from dichloromethane/hexane to give 46 g of 7-bromo-4,4,6-trimethyl-3,4-dihydro-1H-quinoline-2-one. The mother liquor was further chromatographed on silica gel(20% ethyl acetate in hexane) to give 6.2 g more of product. (75%). 1H NMR (300 MHz; CDCl3): 1.30 (s, 6 H), 2.33 (s, 3 H), 2.46 (s, 2 H), 7.07 (s, 1 H), 7.10 (s, 1 H), 9.87 (br s, 1 H).

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