Phosphorus oxychloride → 2-benzyl-4-chloro-5-(4-chlorophenyl)pyridazin-3(2H)-one

Temperature

75 °C

A mixture of 2-benzyl-5-(4-chlorophenyl)-4-methoxypyridazin-3(2H)-one (13.8 g, 42.23 mmol) and POCl3 (20.0 mL) was stirred at 75° C. for 4 h. The reaction mixture was cooled to RT and concentrated under reduced pressure. The residue was cooled in an ice bath and water (200 mL) was added. The undissolved material was filtered and washed with water (3×150 mL). To the solid thus obtained was added MeOH (100 mL). The resultant mixture was sonicated for 10 mins, and then was filtered. The collected solid was washed with MeOH (2×50 mL). The solid was then dried in an vacuum oven at 50° C. to give the title compound, 2-benzyl-4-chloro-5-(4-chlorophenyl)pyridazin-3(2H)-one, (9.2 g, 66%) as a light brown solid. HPLC: 3.75 min; M+H=331. 1H NMR (CDCl3, 500 MHz): δ 7.73 (1H, s), 7.50 (2H, d, J=10.0 Hz), 7.47 (2H, d, J=10.0 Hz), 7.42 (2H, d, J=10.0 Hz), 7.30-7.38 (3H, m), 5.39 (2H, s).

1. temperatureThe reaction mixture was cooled to RT
2. concentrationconcentrated under reduced pressure
3. temperatureThe residue was cooled in an ice bath
4. additionwater (200 mL) was added
5. filtrationThe undissolved material was filtered
6. washwashed with water (3×150 mL)
7. customTo the solid thus obtained
8. filtrationwas filtered
9. washThe collected solid was washed with MeOH (2×50 mL)
10. customThe solid was then dried in an vacuum oven at 50° C.

ORD record

ord-93c59fb79ae047b4aeab94af3e1abd4f

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07378418B2