Three-component synthesis of hexahydropyridopyrimidine- spirocyclohexanetriones induced by microwave
Pyridopyrimidine-spirocyclohexanetriones (5, 6) and pyrimido[4,5-b] quinolinones (8) were obtained in a three-component microwave-assisted reaction of 6-aminopyrimidin-4-ones (1) with dimedone (2) and formaldehyde solution or paraformaldehyde, respectively. A mechanism is proposed based on the presence of a basic catalyst (triethylamine in this case) and the fact that single condensation intermediates are isolated prior to the cyclization leading to the final products.
4-Amino-5-(2-hydroxy-4,4-dimethyl-6-oxocyclohexenylmethyl)-1-methyl-2- (methylsulfanyl)pyrimidin-6(1H)-one: Hydrogen-bonded chains are π-stacked in pairs
Molecules of the title compound, C15H21N3O3S, have a markedly polarized electronic structure; the carbocyclic ring adopts an envelope conformation and the overall molecular conformation appears to be controlled by two intramolecular hydrogen bonds, one each of the O-H...O and N-H...O types. The molecules are linked into C(6) chains by an intermolecular N-H...O hydrogen bond, and pairs of these hydrogen-bonded chains are linked by a π-π stacking interaction.
Low, John N.,Cobo, Justo,Cruz, Silvia,Quiroga, Jairo,Glidewell, Christopher