Piperidine → HCID 20327618, compound

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Reaction Steps

Piperidine (2.56 g, 0.03 mole) is added to 1,2-dimethyl-3-chloro-5-phenylpyrazolium methyl sulfate (4.77 g, 0.015 mole) in absolute ethanol (30 ml) and the mixture stirred with a bar magnet and heated under reflux for 4 hours. After cooling, the reaction mixture is evaporated under reduced pressure to a brown oil, and then dissolved in 50 ml of aqueous saturated sodium bicarbonate solution. The aqueous layer is extracted with ether and this organic layer discarded, then with chloroform. Evaporation of the chloroform layer affords 1,2-dimethyl-3-phenyl-5-piperidinopyrazolium methyl sulfate as a viscous oil. The oil is redissolved in water and saturated aqueous potassium iodide solution is added. An immediate copious white precipitate of 1,2-dimethyl-3-phenyl-5-piperidinopyrazolium iodide is formed, then filtered and washed with ice cold water to give 3.37 g, (56%) of product having a melting point ranging from 179° C. to 180° C. The melting point is unchanged by dissolving in chloroform, filtering and reprecipitating with diethyl ether and filtering off the solid. The analysis of resultant product is set forth below in Table I, compound 1, following Example 12, hereinbelow.

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