p-Toluenesulfonic acid → 2-Methyl-2-(4-nitrophenyl)-1,3-dioxolane

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Reaction Steps

P-Nitroacetophenone (1.65 g, 10 m mol), ethylene glycol (5 ml, 89 m mol), triethyl orthoformate (2.96 g, 20 m mol), and p-toluenesulfonic acid (0.086 g, 0.5 m mol) were combined in methylene chloride (4 ml). The solution was heated with an oil bath (50°-70° C., 6 hrs), cooled to room temperature, and poured into excess 10% sodium hydroxide solution. The phases were separated and the aqueous phase was extracted twice with methylene chloride. The combined organic phase was washed three times with water and dried with anhydrous sodium sulphate. Evaporation of the solvent left a light yellow product (1.78 g) with mp. 69°-71° C., [lit. 73°-75° C., see J. Pharm. Sci. 57, 784 (1968)].

Provenance & Evidence