Regioselective C(sp2)–H halogenation of pyrazolo[1,5-a]pyrimidines facilitated by hypervalent iodine(iii) under aqueous and ambient conditions

An efficient and mild approach has been developed for the regio-selective direct C3 halogenation of pyrazolo[1,5- a ]pyrimidines employing readily available potassium halide salts and a hypervalent iodine( iii ) reagent at ambient temperature.