Ammonium Hydroxide → 1,2,3,4-Tetrahydro-5H-[1,3]benzodioxolo[5',6':5,6]pyrano[3,4-c]pyridin-5-one hydrochloride

Beteiligte Stoffe

Reaktionsschritte

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.

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