3-Chloro-2-polyfluoroalkyl- and 3-chloro-6-nitro-2-polyfluoroalkylchromones were synthesized. These compounds react with N(2)H(4)(.)2HCl on boiling in ethanol to form 4-chloro-3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles.
Electrophilic nitration of 2-trifluoromethylchromone and its 6- and 7-methoxy derivatives affords 6-, 5-, and 8-nitro derivatives, respectively, while 5,7-dimethyl-2-trifluoromethylchromone yields a 6,8-dinitro derivative. Radical chlorination results in 3-chloro derivatives.
The reactions of 3-chloro-2-(polyfluoroalkyl)chrom ones with hydroxylamine in the presence of sodium acetate proceed with ring contraction to form benzofuran derivatives.