Phenylhydrazine → 1-phenyl-6,7-dihydro-1H-indazol-4(5H)-one

To a stirred solution of 2-((dimethylamino)methylene)cyclohexane-1,3-dione (14 g, 83 mmol) in methanol (150 mL) was added phenyl hydrazine (8.92 g, 83 mmol). The reaction mixture was refluxed for 6 hours. The reaction was then concentrated under reduced pressure followed by the addition of n-butanol (130 mL) and glacial acetic acid (2 mL). The reaction mixture was refluxed for 3 hours. On the completion of the reaction, the reaction mixture was concentrated under reduced pressure. The residue was triturated with ether (100 mL) to give a precipitate, which was filtered and dried under reduced pressure to give the desired product (4.6 g, 30%) as a solid. 1H NMR (DMSO-d6, 400 MHz): δ 9.06 (s, 1H), 7.59-7.51 (m, 4H), 7.45-7.40 (m, 1H), 3.00 (t, J=6.4 Hz, 2H), 2.58 (t, J=6.4 Hz, 2H), 2.21 (quintet, J=6.4 Hz, 2H). LCMS [M+H]: 213.

1. temperatureThe reaction mixture was refluxed for 6 hours
2. concentrationThe reaction was then concentrated under reduced pressure
3. additionfollowed by the addition of n-butanol (130 mL) and glacial acetic acid (2 mL)
4. temperatureThe reaction mixture was refluxed for 3 hours
5. customOn the completion of the reaction
6. concentrationthe reaction mixture was concentrated under reduced pressure
7. customThe residue was triturated with ether (100 mL)
8. customto give a precipitate, which
9. filtrationwas filtered
10. customdried under reduced pressure

ORD record

ord-0ac9577ac9ab41f19ad1b6440421014c

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08263610B2