Potassium Hydroxide → 6-(2,4-dichloro-phenylsulfanyl)-2H-pyridazin-3-one

Potassium t-butoxide (1.1 g) was added to a solution of 2,4-dichlorothiophenol (1.8 g) in N,N-dimethylformamide (DMF) (5 mL). The mixture was stirred at room temperature for 10 minutes and then 6-chloro-2H-pyridazin-3-one (1.31 g) was added. The reaction mixture was stirred at 100° C. for five hours. The mixture was then cooled to room temperature, poured into water (20 mL) and 20% potassium hydroxide (5 mL) was added. The resulting dark solution was extracted with ethyl acetate (2×10 mL). The aqueous layer was collected and the pH was adjusted to 3 with concentrated hydrochloric acid. The solution was then extracted with ethyl acetate (3×10 mL). The ethyl acetate layer was collected, dried over anhydrous sodium sulfate, filtered and evaporated to obtain a crude product, which was purified by silica gel chromatography (1:1 ethyl acetate/hexane as eluent) to afford 6-(2,4-dichloro-phenylsulfanyl)-2H-pyridazin-3-one (418 mg, 15%); NMR 6.88 (d, 1H), 7.10 (d, 1H), 7.24(dd, 1H), 7.48 (d, 1H), 7.52 (d, 1H).

1. stirringThe reaction mixture was stirred at 100° C. for five hours
2. temperatureThe mixture was then cooled to room temperature
3. additionwas added
4. extractionThe resulting dark solution was extracted with ethyl acetate (2×10 mL)
5. customThe aqueous layer was collected
6. extractionThe solution was then extracted with ethyl acetate (3×10 mL)
7. customThe ethyl acetate layer was collected
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationfiltered
10. customevaporated
11. customto obtain a crude product, which
12. customwas purified by silica gel chromatography (1:1 ethyl acetate/hexane as eluent)

ORD record

ord-e70fdd1aaa7e46138ced0616b8411392

Source dataset

uspto-grants-2005_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06872722B2