The Dimroth Rearrangement in the Heterocyclic Compounds Synthesis

The Dimroth rearrangement is a fundamental development in heterocyclic chemistry, enabling the nitrogen atoms to isomerize within diverse heterocyclic frameworks. This review provides a comprehensive examination of its mechanistic pathways—including classical ANRORC-type mechanisms—and explores its synthetic utility across various heterocyclic systems, such as pyrimidines, quinazolines, triazoles, and triazines. Emphasis is placed on its growing importance in medicinal chemistry, where it facilitates the efficient synthesis of bioactive scaffolds found in antiviral agents and anticancer therapeutics. The rearrangement has been effectively implemented in the development and synthesis of powerful quinazoline-based compounds such as vandetanib and AZD8931, as well as newer fused triazolo- and chromeno-pyrimidine derivatives. The review highlights recent advancements in reaction conditions, including microwave-assisted protocols and environmentally benign processes, enhancing both yield and selectivity. Factors influencing the rearrangement—such as pH, substituent effects, and reaction media—are critically discussed to guide future applications. Additionally, examples from industrial pharmaceutical synthesis underscore the rearrangement’s practical value beyond academic research. By integrating classical chemistry with modern synthetic needs, the Dimroth rearrangement continues to serve as a powerful and versatile tool in heterocyclic design and drug discovery, with significant potential for further innovation in constructing complex, pharmacologically relevant molecules.