反应详情

30 parts of 2-amino-5,6-dimethoxy-3,4-dihydro-1(2H)-naphthalenone hydrochloride is subjected to boiling reflux in 500 volume parts of a 47 % aqueous solution of hydrogen bromide for 3 hours and, then, concentrated to dryness under reduced pressure. The residue is dissolved in methanol, followed by the addition of ethyl acetate, whereupon crystals separate. Filtrative recovery yields 31 parts of 2-amino-5,6-dihydroxy-3,4-dihydro-1(2H)-naphthalenone hydrobromide.

1. concentrationconcentrated to dryness under reduced pressure
2. dissolutionThe residue is dissolved in methanol
3. additionfollowed by the addition of ethyl acetate, whereupon crystals
4. customseparate