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

Temperature

100 °C

Di-tert-butyl 1-(3,3-dimethyl-1H-inden-5-yl)hydrazine-1,2-dicarboxylate 4b (2.70 g, 7.18 mmol) was dissolved in 100 mL of acetic acid followed by addition of 20 mL of trifluoroacetic acid. After the mixture was reacted at room temperature for 2 hours, ethyl acetoacetate (0.98 g, 7.54 mmol) was added. Then the mixture was heated to 100° C. and reacted for 2 hours. The mixture was cooled to room temperature and concentrated under reduced pressure to remove acetic acid. The reaction mixture was neutralized by saturated sodium bicarbonate solution, and then was extracted with ethyl acetate. The combined organic extracts were washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound 2-(3,3-dimethyl-indan-5-yl)-5-methyl-2,4-dihydro-pyrazol-3-one 4c (1.0 g, yield 47.7%) as a light brown solid.

1. customAfter the mixture was reacted at room temperature for 2 hours
2. customreacted for 2 hours
3. temperatureThe mixture was cooled to room temperature
4. concentrationconcentrated under reduced pressure
5. customto remove acetic acid
6. extractionwas extracted with ethyl acetate
7. washThe combined organic extracts were washed with saturated brine
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. customThe resulting residue was purified by silica gel column chromatography

ORD record

ord-9f3177a130964b94aa00c6894d29de95

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08642637B2