One pot synthesis of spiro pyrimidinethiones/spiro pyrimidinones, quinazolinethiones/quinazolinones, and pyrimidopyrimidines

Condensation of cyclohexane-1,3-dione/barbituric acid, thiourea/urea, and aromatic aldehyde in the mole ratio of 1:1:3 in solventless reaction in presence of NiCl2/KI afforded 1,5-diaryl-3-thioxo-2,4- diazaspiro[5.5]undecane-7,11-dione/1,5-diaryl-2,4-diazaspiro[5.5]undecane-3,7,11-trione analogues and 7,11-diaryl-9-thioxo-2,4,8,10-tetraazaspiro[5.5]undecane-1,3,5,-trione/7,11-diaryl-2,4,8,10-tetraazaspiro[5.5] undecane-1,3,5,9-tetraone analogues, respectively. The similar condensation of cyclohexane-1,3-dione/cyclohexanone, thiourea/urea, and aromatic aldehyde/heteroaromatic aldehyde in the mole ratio of 1:1:1 in refluxing methanol afforded 4-aryl/heteroaryl-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinazolin-5-one, 4-aryl/heteroaryl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-dione analogues and 4-aryl/heteroaryl-1,2,3,4,5, 6,7,8-octahydroquinazoline-2-thione, 4-aryl/heteroaryl-1,2,3,4,5,6,7,8-octahydroquinazolin-2-one analogues, respectively. Condensation of heterocyclic active methylene compound, barbituric acid, thiourea/urea, and aromatic aldehydes under similar set of conditions in 1:1:1 mole ratio was carried which afforded 5-aryl-7-thioxo-1,2,3,4,5,6,7,8-octahydropyrimido[4,5-d]pyrimidine-2,4-dione/5-aryl-1,2,3,4,5, 6,7,8-octahydropyrimido[4,5-d]pyrimidine-2,4,7-trione analogues. Similar condensation of an active methine compound, 2-acetylcyclohexanone, thiourea/urea, and aromatic aldehydes in the mole ratio of 1:1:1 produced 5-aryl-1-methyl-3-thioxo-2,4-diazaspiro[5.5]undec-1-en-7-one/5-aryl-1-methyl-2, 4-diazaspiro[5.5]undec-1-ene-3, 7-dione analogues, the spiro compounds of entirely different kind. All these identifications and characterizations have been based on the elemental analysis and spectral data. J. Heterocyclic Chem., (2010).