Water → HCID 21961318, compound

Participants

Reaction Steps

To a solution of tert-butyl 3-bromo-4-methoxy-2,5,6-trimethylphenylcarbamate (27.8 g, 80.8 mmol) in tetrahydrofuran (150 ml) was added at -78° C. n-butyllithium (1.6 M, 110 ml, 176 mmol) and the reaction mixture was stirred at the same temperature for 20 minutes. To the reaction solution was added 2-methyl-1-(4-methylphenyl)propan-1-one (13.1 g, 80.7 mmol) and the resulting mixture was stirred at room temperature for 1 hour. Water (150 ml) was added into the reaction mixture and the product was extracted three times with ethyl acetate. The combined organic layers were washed with water, dried on magnesium sulfate, filtered, and then concentrated under reduced pressure to obtain 26.0 g of tert-butyl 3-[1-hydroxy-2-methyl-1-(4-methylphenyl)propyl]-4-methoxy-2,5,6-trimethylphenylcarbamate as a crude product. A mixture of this compound and 47% hydrobromic acid (100 ml) was refluxed with heating for 4 hours under an argon atmosphere. The reaction mixture was cooled down to room temperature and neutralized with an 8 N aqueous solution of sodium hydroxide. The product was extracted twice with ethyl acetate. The combined extracts were washed with an aqueous saturated solution of sodium hydrogen carbonate, dried on magnesium sulfate, filtered, and then concentrated under reduced pressure. The residue was crystallized from isopropyl ether-hexane to obtain 14.8 g (62% yield) of the title compound. Melting point: 114-115° C.

Provenance & Evidence