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We have demonstrated the direct substitution of 9H-xanthen-9-ol with different nucleophilic reagents such as thiazoles, triazoles,tetrazoles,hydrazines and hydrazinecarboxamides in good to high yields.This reaction catalyzed by ferric hydrogensulfate as a heterogeneous acid catalyst in ethanol through S_N1 type reaction of pyrylium with a nucleophilic reagent afforded the heterocycle- and aromatic-N-substituted xanthene derivatives as simple marked molecules in short reaction times.
We have demonstrated the direct substitution of 9H-xanthen-9-ol with different nucleophilic reagents such as thiazoles, triazoles, tetrazoles, hydrazines and hydrazinecarboxamides in good to high yields.This reaction catalyzed by ferric hydrogensulfate as a heterogeneous acid catalyst in ethanol through S_N1 type reaction of pyrylium with a nucleophilic reagent afforded the heterocycle- and aromatic-N-substituted xanthene derivatives as simple marked molecules in short reaction times.