The acylation of amines has always attracted a deep interest as a synthetic route due to its high versatility in organic chemistry and biochemical processes. The purpose of this article is to depict a mechanochemical acylation procedure based on the use of acyl-saccharin derivatives, namely N-formylsaccharin, N-acetylsaccharin and N-propionylsaccharin. This protocol furnishes a valuable solventless alternative to the existing processes and aims to be highly beneficial in multi-step procedures due to its rapid and user-friendly workup.

The synthesis of nitrogen-based heterocycles has always been considered essential in the development of pharmaceuticals in medicine and agriculture. This explains why various synthetic approaches have been proposed in recent decades. However, performing as methods often imply harsh conditions or the employment of toxic solvents and dangerous reagents. Mechanochemistry is undoubtedly one of the most promising technologies currently used for reducing any possible environmental impact due to the worldwide interest in developing solvent-free synthetic pathways. Following this line, we propose a renewed mechanochemical protocol for synthesizing various heterocyclic classes by exploiting the reducing proprieties and the electrophilic nature of thiourea dioxide (TDO). Simultaneously using the ready availability and low cost of a component of the textile industry such as TDO and all the advantages brought by a green technique such as mechanochemistry, we plotted the route towards a more sustainable and eco-friendly methodology for obtaining heterocyclic moieties.