Sulfuric Acid → 1-[2-(4-Chloro-2-phenyl-1H-imidazo[4,5-c]quinolin-1-yl)ethyl]-4-piperidinone

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Reaction Steps

A mixture of 0.39 g of 1-[2-(4-chloro-2-phenyl-1H-imidazo[4,5-c]quinolin-1-yl)ethyl]-4,4-ethylenedioxypiperidine and 4 ml of concentrated sulfuric acid was stirred at room temperature for 30 minutes. The reaction mixture was poured into ice-water, adjusted to pH 11 with 10% aqueous sodium hydroxide solution, and extracted with ethyl acetate. The extract was washed with saturated aqueous sodium hydrogencarbonate solution and dried, and then the solvent was evaporated to give 0.42 g of a colorless liquid. The resulting liquid was purified by alumina column chromatography using ethyl acetate—n-heptane (1:1) as an eluting solvent to give 0.32 g of colorless crystals. Recrystallization from isopropanol gave colorless needles having the melting point of from 163 to 165° C.

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