Clean Synthesis in Water: Uncatalyzed Three‐Component Condensation Reaction of 3‐Amino‐1,2,4‐triazole or 2‐Aminobenzimidazole with Aldehyde in the Presence of Activated CH‐Acids

An environment-friendly three-component condensation of 3-amino-1,2,4-triazole or 2-aminobenzimidazole, an aldehyde and activated CH-acid such as β-dicarbonyl compounds and malononitrile, affords the corresponding pyrimidine-based annulated di- and triheterocyclic ring systems. Reactions are performed in water, without the addition of catalyst, and in good yield.