Sodium cyanoborohydride → 1-[2-(4-Nitrophenyl)ethyl]-4-{2-[4-nitro-3-(trifluoromethyl)phenyl]ethyl}piperazin-2-one

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Reaction Steps

A solution of 1-nitro-4-(prop-2-en-1-yl)-2-(trifluoromethyl)benzene in methanol and cooled to −78° C. Ozone was bubbled through the solution until it turned blue. Excess ozone was removed by bubbling nitrogen through the solution, followed by addition of triphenylphosphine (1.1 g, 4.3 mmol). The mixture was warmed up naturally. TLC showed formation of the desired product. The crude material was adsorbed onto silica gel, and purified by flash chromatography to afford the desired [4-nitro-3-(trifluoromethyl)phenyl]acetaldehyde. The aldehyde (20 mg, 0.070 mmol) was treated with 1-[2-(4-nitrophenyl)ethyl]piperazin-2-one (16 mg, 0.070 mmol) and titanium(IV) isopropoxide (0.20 mL). After stirring the mixture for 15 minutes, ethanol (2 mL) and sodium cyanoborohydride (44 mg, 0.70 mmol) was added into the reaction. The mixture was allowed to stir for 4 hours. LC showed formation of the desired product. The reaction was diluted with ethyl acetate, washed with brine, dried over sodium sulfate, and concentrated to give the crude product. The crude product was purified by mass-directed reverse phase HPLC (AcCN-Water with 0.1% TFA). LC-MS (IE, m/z): 467 [M+1]+.

Provenance & Evidence