Green halogenation of aromatic heterocycles using ammonium halide and hydrogen peroxide in acetic acid solvent was written by D’Aleo, Danielle N.;Allard, Sheena R.;Foglia, Cassandra C.;Parent, Shawna L. M.;Rohr, David J.;Gottardo, Christine;MacKinnon, Craig D.. And the article was included in Canadian Journal of Chemistry in 2013.Formula: C6H5NS This article mentions the following:
The green generation of X+ (X = Br, I) using hydrogen peroxide in aqueous acetic acid allows access to aromatic heterocyclic halides in yields and purities comparable to syntheses employing N-bromosuccinimide. In activated and unsubstituted thiophene rings, regioselectivity is quant. for positions to the sulfur; pyrroles also give quant. reactions, at least initially. Deactivated rings, including furans and thiazoles, as well as thiophenes with strongly electron-withdrawing groups showed little to no reactivity under the conditions investigated. The reaction shows remarkable functional group tolerance (to alc., nitro, alkyl, halo, and carbonyl groups), as shown through reaction with substituted phenols. In all bromination reactions, reaction yields and regiochem. were very similar to reactions involving N-bromosuccinimide in THF solvent. In the experiment, the researchers used many compounds, for example, 3-Methylthiophene-2-carbonitrile (cas: 55406-13-8Formula: C6H5NS).
3-Methylthiophene-2-carbonitrile (cas: 55406-13-8) belongs to nitriles. The R-C-N bond angle in and nitrile is 180° which give a nitrile functional group a linear shape. Both the carbon and the nitrogen are sp hydridized which leaves them both with two p orbitals which overlap to form the two π bond in the triple bond. Industrially, the main methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts.Formula: C6H5NS
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts