Fused Pyrimidine-Based Drug Discovery covers all categories of fused-pyrimidines along with pharmacological and in silico studies. It covers the chemistry and biological activities, as well as the design of novel fused-pyrimidine scaffolds. N-Heterocyclic scaffolds are found in most known drug candidates, and are of interest to medicinal and organic chemists to design, synthesize and evaluate their biological properties. A variety of fused-pyrimidine molecules have been synthesized and extracted from natural resources, and are found to exhibit various biological activities such as antifolates, anticancer agents, analgesics, antimetabolites, CNS active agents and many more. Some of these scaffolds like purines are also known to have involvement in biological processes and are part of the framework of genetic material. This book focuses on the classification, structural chemistry, and chemical and physical properties along with various approaches for their synthesis. This book is ideal for researchers in organic chemistry both in academic and industrial settings, postgraduates in chemistry and medicinal chemistry.