Abstract
Common and novel synthesized active methylene compounds as well as heterocycles having active methyl or active methine sites have been used for the synthesis of a wide variety of substituted pyrimidines and pyrimidopyrimidines of interesting medical and pharmaceutical importance. Many synthetic approaches were used for the preparation of target heterocyclic systems such as cyclocondensation reactions, ring-opening ring-closure, cycloaddition, acid-, base-catalyzed reaction, intramolecular cyclization and self-condensation has been reported in this part. Also, three different biological applications namely, antimicrobial activity, cellobiase activity and mollucicidal activities was carried out on some reported pyrimidines and pyrimidopyrimidines.