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Reaction of 1-methylpyrimidine-(1H,3H,5H)-2,4,6-trione (1-MBA 1) as an unsymmetrical barbituric acid with cyanogen bromide and various aldehydes in the presence of triethylamine and/or pyridine afforded diastereomeric mixtures of new class of heterocyclic stable 5-aryl-1,1'-dimethyl- and 5-aryl-3,1'-dimethyl-1H,1'H-spiro(furo(2,3-d)pyrimidine-6,5'- pyrimidine)2,2',4,4',6'(3H,3'H,5H)-pentaones which are dimeric forms of 1-methyl barbiturate at the range of 0 o C to room temperature. In the reaction of some aldehydes with 1-MBA and BrCN were afforded a mixture of diastereomers. Another two aldehydes such as 4-cyano- and 2-hydroxybenzaldehydes gave exclusively two diastereomers in which binded to the salt of triethylammonium hydrobromide by intermolecular H-bond in ratio of 1:1. 4-Hydroxybenzaldehyde and 2-pyridine- carbaldehyde gave exclusively one diastereomer under the same condition. Aldehydes possessing strong electron-donor were produced exclusively two geometric isomers of Knoevenagel adduct (E- and Z-isomers). The structures of compounds were deduced by 1 H NMR, 13 C NMR and FT-IR spectroscopy. Mechanism of the formation is discussed.

journal of the korean chemical society

One-pot Four Component Reaction of Unsymmetrical 1-Methylbarbituric Acid with BrCN and Various Aldehydes in the Presence of Et<sub>3</sub>N and/or Pyridine

One-pot Four Component Reaction of Unsymmetrical 1-Methylbarbituric Acid with BrCN and Various Aldehydes in the Presence of Et3N and/or Pyridine

One-pot Four Component Reaction of Unsymmetrical 1-Methylbarbituric Acid with BrCN and Various Aldehydes in the Presence of Et₃N and/or Pyridine