ABSTRACT:Fused pyrimidine scaffolds serve as a flexible and versatile foundational heterocycle in the field of pharmaceutical development. Thienopyrimidines are a diverse family of molecules characterized by the fusion of a thieno ring with a pyrimidine moiety, resulting in a unique scaffold with promising chemical and pharmacological properties. Thienopyrimidines exhibit multifarious features, mainly, this is due to their structural resemblance with purine bases, such as guanine and adenine. The diverse range of biological effects displayed by thienopyrimidines, such as their ability to combat bacteria, fungi, parasites, cancer and viruses, has inspired us to explore and organize their structure–activity relationship (SAR). Their intricate molecular structures enable them to interact with specific molecular targets, such as enzymes, receptors, and cellular signaling pathways, leading to their therapeutic efficacy. The presence of thienopyrimidine derivatives in several FDA‐approved drugs and clinical trial candidates underscores their therapeutic potential and safety profile. The review elaborates on the primary approach for synthesis of thienopyrimidines, using thiophene derivatives or pyrimidine analogues. As our understanding of their structure–function relationships deepens, we can expect further advancements in the development of thienopyrimidine‐based therapies.
