Hydrochloric Acid → HCID 23036990, compound

Participants

Reaction Steps

15.1 g of the sodium salt of 5-(3-isopropylisoxazol-5-yl)-4-methoxycarbonylcyclohexane-1,3-dione was suspended in 150 ml of tetrahydrofuran; 6.4 g butyryl chloride was added while cooling with ice. After the mixture had been stirred for 15 hours it was filtered and concentrated. The residue obtained was taken up in methylene chloride, 2 g of 4-(N,N-dimethylamino)-pyridine was added, and the mixture was stirred for 3 days. After shaking with 10 wt % hydrochloric acid and then with water, the mixture was dried over sodium sulfate and concentrated. 15 g of 2-butyryl-3-hydroxy-5(3-isopropylisoxazol-5-yl)-4-methoxycarbonylcyclohex-2-en-1-one was obtained as an isomer mixture, and was then stirred with 300 ml of 10 wt % strength sodium hydroxide solution at 25° C. for 16 hours. The pH of the solution was then adjusted to 2 concentrated hydrochloride acid, and stirring was carried out for 2 hours at 85° C. After cooling the product was filtered off, washed with water and recrystallized from isopropanol. There was obtained 2-butyryl-3-hydroxy-5(3-isopropylisoxazol-5-yl)-cyclohex-2-en-1-one of m.p. 105°-107° C. (compound no. 64).

Provenance & Evidence