Trifluoroacetic acid → 1-[4-Nitro-2-(3,3,5,5-tetramethylcyclohex-1-enyl)phenyl]piperazine

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Reaction Steps

A solution of 4-[4-nitro-2-(3,3,5,5-tetramethylcyclohex-1-enyl)phenyl]piperazine-1-carboxylic acid t-butyl ester (300 mg, 0.676 mmol) produced in Example (88b) in dichloromethane (3 mL) was stirred at an external temperature of 0° C. Trifluoroacetic acid (1 mL) was gradually added dropwise thereto over a period of 15 minutes. The reaction mixture was allowed to warm to room temperature while stirring for 90 minutes. While cooled in an ice bath, saturated aqueous solution of sodium hydrogencarbonate to the mixture to make the mixture basic. Extraction was performed with ethyl acetate, and the separated organic layer was washed with water and then dried over anhydrous magnesium sulfate. The desiccant was filtered off and the filtrate was concentrated under reduced pressure. The resultant residue was purified by NH silica gel column chromatography (ethyl acetate/heptane) to give 180 mg of the title compound as a light yellow solid.

Provenance & Evidence