GENERAL METHOD: A mixture of isophthalonitrile (0.5 mmol), 2-aminoethanol (0.65 mmol, 0.040 g), Co(NO3)2 (0.02 mmol, 0.036 g), and sulfur (0.05 mmol, 0.0016 g) was stirred for an appropriate period of time at 90 °C, or reacted under microwave radiation (90 °C, 800 W) for the corresponding Time. For the synthesis of monooxazolines, a mixture of isophthalonitrile (0.5 mmol), 2-aminoethanol (0.65 mmol, 0.040 g), Co(NO3)2 (0.02 mmol, 0.036 g) and sulfur (0.05 mmol, 0.0016 g) was stirred for 3 h at 90 °C or reacted under microwave radiation conditions (90 °C, 800 W) for 3 min . For the synthesis of bisoxazoline, isophthalonitrile (0.5 mmol), 2-aminoethanol (2.6 mmol, 0.159 g), Co(NO3)2 (0.02 mmol, 0.036 g), and sulfur (0.05 mmol, 0.0016 g) were stirred for 10 hr at 110 °C or reacted under microwave radiation conditions (110 °C, 800 W) for 8 minutes. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature, ethyl acetate (6 mL) was added and the catalyst was separated by filtration. After concentration under reduced pressure, the residue was purified by silica gel column chromatography to afford the pure product 1,3-bis(4,5-dihydrooxazol-2-yl)benzene (5a-r).
