p-Toluenesulfonic acid → 1-(3-Methylbenzoyl),3-(3-methylbenzoyl)benzene thiosemicarbazone

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Reaction Steps

p-toluenesulfonic acid (0.018 g, 0.09 mmol) was added to a solution of 1-(3-methylbenzoyl),3-(3-methylbenzoyl)benzene 8 (0.300 g, 0.95 mmol) in anhydrous methanol (10 mL). After stirring at reflux for 10 min, thiosemicarbazide (0.086 g, 0.954 mmol) was added to the reaction mixture and stirred for 12 h under an inert atmosphere of nitrogen gas. After 12 h, methanol was removed under reduced pressure and 10 mL of water was then added. The products were extracted with dichloromethane (2×30 mL) and the combined organic phases were washed with brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. Purification using flash chromatography (silica gel, hexanes:ethyl acetate, gradient 90:10 to 80:20) afforded 1-(3-methylbenzoyl),3-(3-methylbenzoyl)benzene thiosemicarbazone 9 (0.063 g, 0.016 mmol) as a white solid in a 17% yield. HRMS (ESI) calculated for C23H21N3OSH+ (M+H)+ 388.14781, found 388.14793. The product was determined to be approximately 80% pure and was submitted for biological testing without further purification.

Provenance & Evidence