Synthetic Routes and Bioactivity Profiles of the Phenothiazine Privileged Scaffold

This review offers a focused overview of the strategies used to build and modify phenothiazine (PTZ) derivatives. It covers both classical synthetic approaches and advances reported since 2014, including transition metal-catalyzed transformations and greener techniques, such as electrosynthesis, microwave-assisted reactions, and ultrasound-promoted methods. Each strategy is evaluated with respect to efficiency, scalability, and sustainability. In parallel, the review surveys the diverse bioactivity profiles of PTZ derivatives, ranging from antipsychotic, anticancer, and antimicrobial activities to emerging applications in photodynamic therapy and neuroprotection. By correlating synthetic accessibility with biological potential, this review provides an integrated perspective that highlights advances achieved since 2014 and outlines future opportunities for rational PTZ design and applications.