反应详情

A mixture of 3,4-methylenedioxyphenol (125 g, 0.91 moles) and methyl 4-oxo-3-piperidinecarboxylate hydrochloride (125 g, 0.65 moles) is cooled in ice and treated over one hour with 600 ml of 72% sulfuric acid. The mixture is then stirred at room temperature for 64 hours. Ice/water (1.0 kg) is added, followed by conc. ammonium hydroxide, until the pH of the mixture is 9.0. The crude product is filtered, stirred briefly in 2.5% aqueous sodium hydroxide (1.0 l), and refiltered. Several recrystallizations from dilute aqueous hydrochloric acid yielded the product (86.2 g) as the hydrochloride, mp 258°-259° C.

1. temperatureis cooled in ice
2. filtrationThe crude product is filtered
3. stirringstirred briefly in 2.5% aqueous sodium hydroxide (1.0 l)
4. customSeveral recrystallizations from dilute aqueous hydrochloric acid