Imidazoles have always manifested fascinating biological properties and many of these molecules have been individually elaborated to pharmaceuticals. They represent one of two major classes of antifungal azole derivatives: the imidazole group has contributed significantly to the therapy of both superficial and systemic mycotic infections. Azaheterocycles constitute a very important class of compounds. In particular, pyrimidine derivatives include a large number of natural products, pharmaceuticals, and functional materials. While development of important methodologies for the synthesis of pyrimidines enjoys a rich history, the discovery of new strategies for the convergent synthesis of pyrimidines remains a vibrant area of chemical research. Azetidin, -azetin, 2-azetin and azete are the nitrogen analogues of cyclobutane, cyclobutene and cyclobutadiene respectively. To overcome the -lactam resistance there are several ideas; to develop new class of antibiotics unsusceptible to the resistant mechanisms, alter the structure of the - lactams, rendering them insensitive to hydrolysis, use of hybrid drugs which can kill bacteria."