Typical experimental procedure: To a suspension of ferrous sulfate (1.73g, 6.2 mmol) in acetic acid (15 ml) is added half of a solution of sodium nitrite (0.79g, 11.3 mmol) in water (8 ml) under an inert atmosphere (all solutions must also be thouroughly degassed beforehand). The remaining is added simultaneously with a solution of the isoxazolone (1.13 mmol) in a little degassed acetic acid over 30 minutes. The set-up is then flushed with nitrogen for a few minutes, water ...