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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence