Daniel Barrena-Espés

1 Introduction Aromatic compounds with high nitrogen content, such as s-heptazine or s-tetrazine derivatives, have attracted considerable interest due to their exceptional structural and electronic characteristics [1, 2]. Specifically, the heptazine core presents a rigid and planar polycyclic aromatic framework with a particularly high nitrogen content, resulting in a low carbon-to-nitrogen ratio (C/N = 0.85).

Thioamides constitute a fundamental class of sulfur-containing compounds that are broadly significant in biology, (1−3) organocatalysis, (4,5) and materials science. (6) Their structural resemblance to amides, coupled with the unique influence of the sulfur atom, imparts distinct physicochemical and biological properties that make them attractive in diverse fields.

Thioamides are found in a variety of essential biomolecules (such as peptides, protein backbones, and DNA), (1) as well as in natural products and pharmaceuticals. (2) Beyond their biological relevance, thioamide-based chemical derivatives have attracted significant attention in synthetic organic chemistry due to their versatile applications. For example, they are used in the preparation of sulfur-based heterocycles, such as thiazoles and thiazolines, through reactions with dielectrophilic agents.