The proton sponge–triethylamine tris(hydrogen fluoride) mixture provides a mild and efficient fluorinatingreagent for the selective introduction of a fluorine atom, by halogen exchange, into dichlorodiazines.
Selective fluorination by halogen exchange of chlorodiazines and chloropyridines promoted by the ‘proton sponge’—triethylamine tris(hydrogen fluoride) system
The ‘proton sponge’—triethylamine tris(hydrogen fluoride) mixtures provide a mild and efficient fluorinating reagent to introduce selectively fluorine atoms by halogenexchange into chlorodiazines and chloronitropyridine series.
3-Chloro-6-phenylpyridazine, 2,3-dichloroquinoxaline and 1,4-dichlorophthalazine were reacted with KF under solvent-free conditions in the presence of a phase transfer agent, with or without microwave irradiation. The chlorine-fluorine exchanges were obtained with enhanced yields and selectivities when compared with previous methods. (C) 2004 Elsevier B.V. All rights reserved.