Trifluoroacetic acid → 2-(2,2-Dimethyl-indan-5-yl)-5-methyl-2,4-dihydro-pyrazol-3-one

Temperature

90 °C

Di-tert-butyl 1-(2,2-dimethyl-1H-inden-5-yl)hydrazine-1,2-dicarboxylate 45c (3.3 g, 8.78 mmol) was dissolved in 12 mL of acetic acid followed by addition of 6 mL of trifluoroacetic acid and 3-oxo-butanoic acid methyl ester (1.5 mL, 13.8 mmol). Upon completion of the addition, the reaction mixture was stirred at 90° C. for 2 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was concentrated under reduced pressure and the residue was diluted with 30 mL of water and 30 mL of ethyl acetate. After mixing well, the separated organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, filtered to remove the drying agent and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound 2-(2,2-dimethyl-indan-5-yl)-5-methyl-2,4-dihydro-pyrazol-3-one 45d (464 mg, yield 22.1%) as a yellow oil.

1. additionUpon completion of the addition
2. concentrationThe mixture was concentrated under reduced pressure
3. additionthe residue was diluted with 30 mL of water and 30 mL of ethyl acetate
4. additionAfter mixing well
5. washthe separated organic layer was washed with saturated brine
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. customto remove the drying agent
9. concentrationconcentrated under reduced pressure
10. customThe residue was purified by silica gel column chromatography

ORD record

ord-a482bc76058f4f6dbec0ab3e6e4c77bb

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367710B2