Cyanoguanidine as a versatile building block in organic synthesis

Cyanoguanidine, or dicyandiamide, is a bifunctional, nitrogen-rich compound that acts as both an electrophile and a nucleophile in organic reactions due to the presence of cyano and guanidino groups. Rapid developments in cyanoguanidine-based transformations during the last five years have significantly increased its synthetic value in organic synthesis. It has been used as a building block in the synthesis of various nitrogen-rich heterocycles, including pyrimidines, triazines, imidazoles, benzimidazoles, and tetrazoles. Cyanoguanidine′s reactivity and structural flexibility make it a desirable choice for synthetic chemists seeking low-cost, environmentally safe, and atom-efficient methods. This review brings together the expanding synthetic utility of cyanoguanidine as a multifunctional, eco-compatible reagent, which may open new avenues of research in organic synthesis. Additionally, this article highlights the use of cyanoguanidine-derived structures to medicinal, polymer, and materials chemistry. The bibliography includes 82 references.