Hydrochloric Acid → (+/-)-6-(4'-Butanoyloxyphenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone

A 100 ml round-bottomed flash was charged with pyridine (30 ml) and 7.10 g (34.8 mmol) of (±)-4,5-dihydro-6-(4'-hydroxyphenyl)-5-methyl-3(2H)-pyridazinone from Example I, then cooled to 0° C. under an atmosphere of nitrogen. Butanoyl chloride (4.10 g, 38.3 mmol) was added dropwise to the solution via syringe. The reaction mixture was stirred for 30 min at 0° C., warmed to 23° C. over 15 min then poured into 1N aqueous hydrochloric acid (400 ml). The aqueous solution was extracted with EtOAc (2×200 ml). The combined EtOAc extracts were successively washed with 5% aqueous sodium bicarbonate solution (300 ml), saturated aqueous sodium chloride (200 ml), dried over anhydrous magnesium sulfate (5 g), filtered and concentrated in vacuo to provide 9.8 g of crude product as a solid. Recrystallization from ethyl acetate/hexanes (2:1, 35 ml) yielded 7.61 g (80%) of pure (±)-6-(4'-butanoyloxyphenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone as colorless needles, m.p. 112°-113° C.

1. temperaturewarmed to 23° C. over 15 min
2. extractionThe aqueous solution was extracted with EtOAc (2×200 ml)
3. washThe combined EtOAc extracts were successively washed with 5% aqueous sodium bicarbonate solution (300 ml), saturated aqueous sodium chloride (200 ml)
4. dry with materialdried over anhydrous magnesium sulfate (5 g)
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto provide 9.8 g of crude product as a solid
8. customRecrystallization from ethyl acetate/hexanes (2:1, 35 ml)

ORD 기록

ord-001b3ab8a7d845158201e89385301ae0

출처 데이터셋

uspto-grants-1991_10

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US05053338