2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 1-phenyl-1H-pyrazol-3-amine

To a solution of 1-phenyl-3-amino-pyrazoline(7.4 g, 46 mmol) in dioxane (200 mL) was added 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (11.54 g, 50 mmol). After addition, the reaction was stirred at RT for 1 hour, then the resulting dark solution was filtered through a pad of Celite. The filtrate was acidified with 1N aqueous HCl (100 mL) and extracted with CH2Cl2 (50 mL). The organic layer was extracted with 1N aqueous HCl (50 mL). The combined aqueous layers were washed with CH2Cl2 (2×50 mL), then adjusted to pH12 with NaOH, followed by extraction with CH2Cl2 (3×100 mL). The combined CH2Cl2 extracts were washed with saturated NaCl (100 mL), dried (MgSO4), and concentrated under reduced pressure to give the title compound, 1-phenyl-3-amino-pyrazole as light orange solid (3.0 g, 41% yield). LC/MS (method A): retention time=1.43 min, (M+H)+=160.

1. additionAfter addition
2. filtrationthe resulting dark solution was filtered through a pad of Celite
3. extractionextracted with CH2Cl2 (50 mL)
4. extractionThe organic layer was extracted with 1N aqueous HCl (50 mL)
5. washThe combined aqueous layers were washed with CH2Cl2 (2×50 mL)
6. extractionfollowed by extraction with CH2Cl2 (3×100 mL)
7. washThe combined CH2Cl2 extracts were washed with saturated NaCl (100 mL)
8. dry with materialdried (MgSO4)
9. concentrationconcentrated under reduced pressure

ORD record

ord-459c0d295a9b4b38ad5446a50ecf7a32

Source dataset

uspto-grants-2008_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07361766B2