Two Directions of the Reaction of 4-Bromobenzaldehyde with Substituted Acetophenones and Urea. Synthesis of Aryl-substituted Pyrimidin-2-one and Hexahydropyrimido[4,5-d]pyrimidin-2,7-dione

Condensation of 4-bromobenzaldehyde, urea, and 4-alkyl-substituted acetophenones gave substituted hexahydro-1H,8H-pyrimido[4,5-d]pyrimidin-2,7-diones or 1H-pyrimidin-2-ones, depending on the substituent on the acetophenone ring and the nature of the solvent (i-PrOH, BuOH, AcOH). The corresponding 5-bromopyrimidin-2-ones were formed on bromination of these compounds. The structures of these compounds were confirmed by IR, UV, and ¹H NMR spectroscopy.