p-Toluenesulfonic acid → 3-Methyl-6-phenyl-1,2,4-triazine 4-oxide

Participants

Reaction Conditions

Reaction Steps

To a solution of hydrazono-phenyl-acetaldehyde oxime (28 g, 168 mmol) at room temperature under nitrogen in dichloromethane (300 ml) was added trimethyl orthoacetate (19 ml, 168 mmol) and p-toluenesulfonic acid (1.6 g, 8.4 mmol). The reaction mixture was stirred for 18 h and then concentrated in vacuo. Xylene (300 ml) was added followed by trimethyl orthoacetate (19 ml, 168 mmol) and the mixture heated to 130° C. for 2 h. The reaction mixture was evaporated in vacuo. The residue was purified by flash chromatography (SiO2; 50% EtOAc in hexanes) and the product was recrystallised from a mixture of dichloromethane and ethyl acetate to afford the title compound as a white solid (11.5 g). δH (400 MHz; CDCl3) 2.86 (3H, s), 7.57 (3H, m), 7.99 (2H, m), 8.52 (1H, s). m/z (ES+) 188 (M+1).

Provenance & Evidence