in pyridine T=100°C; 3 h; sealed tube;

1: 1.) n-butyllithium, 2.) O-(2,4-dinitrophenyl)hydroxylamine / 1.) THF, hexane, -35 deg C, 10 min, 2.) -10 deg C, 15 min; R.T., 24 h. 2: 70 percent / pyridine / 3 h / 100 °C / sealed tube View Scheme

4 h; Heating;