Three-component cyclocondensation of 5-nitrothiophene-2-carbaldehyde with cyclohexanone and C -aminotri(tetr)azoles. Formation paths of isomeric hexahydrotriazoloquinazolines

Three-component condensation of 5-aminotetrazole with 5-nitrothiofene-2-carbaldehyde and cyclohexanone selectively afforded linearly fused 9-(5-nitrothiophen-2-yl)-4,5,6,7,8,9-hexahydrotetrazolo[5,1-b]-quinazoline. Analogous reaction of 3-amino-4H-1,2,4-triazole gave a mixture of linearly and angularly fused isomeric hexahydrotriazoloquinazolines. Probable reaction paths were experimentally justified by the isolation of the corresponding intermediate products whose structure was determined with the aid of one- and twodimensional NMR techniques.