Strategies for the synthesis of heterocyclic compounds based on 1,2-bis(thiocarbamoyl)hydrazines: A literature review

Derivatives of 1,2-bis(thiocarbamoyl)hydrazines have attracted considerable attention due to their high synthetic potential and ability to serve as versatile precursors in the construction of various heterocyclic systems. These compounds are efficient building blocks for the synthesis of a wide range of heterocycles, including 1,3,4-thiadiazoles, triazoles, 1,3-thiazoles, dithiadiazepines, 1,3,4-thiadiazines, thiazepines, pyrazolo[1,2-c][1,3,4]thiadiazoles, imidazo[2,1-b][1,3,4]thiadiazoles, triazaphospholes, and other condensed systems. This review systematizes modern approaches to the synthesis of heterocyclic compounds based on 1,2-bis(thiocarbamoyl)hydrazines, in particular oxidative desulfurization reactions, alkylation, interactions with acids and bases, α-halocarbonyl compounds, hydrazonoyl halides, isocyanide dichlorides, ethenecarbonitriles, haloquinones, acetylenedicarboxylates, and related reagents. Particular attention is paid to the analysis of the reactivity of these compounds, key synthetic strategies, and factors that determine the direction of heterocyclization reactions. The review summarizes current literature data and outlines prospects for the further application of 1,2-bis(thiocarbamoyl)hydrazines as versatile synthetic platforms in heterocyclic chemistry.