Polychloroheteroaromatic Compounds

Development of potential manufacturing routes for substituted thiophenes – Preparation of halogenated 2-thiophenecarboxylic acid derivatives as building blocks for a new family of 2,6-dihaloaryl 1,2,4-triazole insecticides

“…[ 21 ] However, since 2-thiophenecarbonitrile 20 was commercially available, we investigated the vapor phase chlorination of this starting material as a potential convenient manufacturing route to 3 that could be carried out on a multi-Kg scale (Scheme 3 ). [ 22 , 23 ] The vapor phase chlorination of nitrogen heterocycles has been reported. [ 22 ] The analogous vapor phase chlorination of thiophene 20 was carried out in the present study using a down flow quartz reactor tube heated with an electric furnace to high temperatures, and filled with an inert support of grade 03 silica gel, which generated a high surface area reaction zone.…”

Perhalogenated pyrimidine scaffolds. Reactions of 5-chloro-2,4,6-trifluoropyrimidine with nitrogen centred nucleophiles

“…Pyrimidines are electron-deficient aromatic systems and, when halogenated, become very useful substrates for a variety of nucleophilic aromatic substitution (S N Ar) processes [ 9 ] and, since numerous chloropyrimidines are commercially available, there have been many reports of synthetic strategies concerned with creating pyrimidine-based libraries from halogenated core scaffolds. For example, recently, synthesis of an inhibitor of the cyclin-dependent kinase was developed [ 10 ] ( Scheme 1 ) starting from 2,4,6-trichloropyrimidine as the core scaffold.…”