Substituted aniline (0.1 mmol) in MeOH (50 mL) was treated with 30% aq glyoxal (16.2 mL, 0.1mmol) for 16 h at rt A yellowish mixture was formed. NH 4 Cl (10.7g, 0.2 mol) was added followed by 37% aq formaldehyde (16 mL, 0.2 mol). The mixture was diluted with MeOH (400 mL) and the resulting mixture was refluxed for 1 h. H 3 PO 4 (14 mL, 85%) was added over a period of 10 min. The resulting mixture was then stirred at reflux for a further 4-8 h. The reaction ...
