Methanol → 2-(2,3-Dihydro-benzofuran-5-yl)-5-methyl-2,4-dihydro-pyrazol-3-one

Bis(2,2,2-trichloroethyl) 1-(2,3-dihydrobenzofuran-5-yl)hydrazine-1,2-dicarboxylate 7b (2.9 g, 5.8 mmol) was dissolved in 50 mL of ethanol and 5 mL of methanol followed by addition of zinc powder (10.8 g, 166 mmol) and aqueous ammonium acetate (15 mL, 1 mol/L) and the mixture was reacted at room temperature for 1 hour. Then ethyl acetoacetate (0.75 mL, 5.9 mmol) was added dropwise. The reaction mixture was heated to reflux for 2 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The reaction was cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography to obtain the title compound 2-(2,3-dihydro-benzofuran-5-yl)-5-methyl-2,4-dihydro-pyrazol-3-one 7c (706 mg, yield 56.5%) as a yellow solid.

1. customthe mixture was reacted at room temperature for 1 hour
2. temperatureThe reaction mixture was heated
3. temperatureto reflux for 2 hours
4. filtrationfiltered
5. concentrationThe filtrate was concentrated under reduced pressure
6. customthe residue was purified by silica gel column chromatography

ORD record

ord-0f8fdde974ed49929712f5cbf70bb9fc

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367710B2