Abstract
A novel, facile, one-pot, multicomponent reaction for the synthesis of a series of pyrano[2,3-d][1,2,4] triazolo[4,3-a]pyrimidine and pyrano[2',3':4,5] pyrimido[2,1-b][1,3,5]thiadiazine derivatives has been developed from reaction of 2,4-dichlorobezaldehyde, malononitrile, and the appropriate active methylene compounds in refluxing dioxane in the presence of chitosan. A plausible mechanism has been proposed for this reaction, and the structure of the newly synthesized compounds was all established on the basis of spectral data (mass, IR, and H-1-NMR) and elemental analyses.