64001-11-2

123-30-8

122-51-0

64001-11-2

GENERAL METHODS: Fe3O4WO3-EAE-SO3H(III) (0.01 g) was added to a solution in water (5 mL) containing 4-aminophenol (0.093 g, 1.0 mmol), triethyl orthoformate (0.177 g, 1.2 mmol) and 1-butyl-3-methylimidazolium azide (0.216 g, 1.2 mmol). The reaction mixture was magnetically stirred at 60 °C for 30 min. Upon completion of the reaction (monitored by TLC), the mixture was cooled to room temperature and the catalyst was separated with an external magnet. The resulting solution was extracted with EtOAc (3 x 15 mL). The organic layers were combined, washed with brine, dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was recrystallized with ethyl acetate/hexane (1/9 v/v) to give pure 4-tetrazol-1-ylphenol (1.48 g, 95% yield). The recovered catalyst was washed with hot ethyl acetate and dried at 60 °C for 2 h for subsequent recycling.