V. I. Saloutin, Z. Skryabina, I. T. Bazyl'
Feb 11, 1999
Citations
0
Influential Citations
12
Citations
Journal
Journal of Fluorine Chemistry
Abstract
Abstract Polyfluorobenzopyranopyrazoles(isoxazoles) have been prepared via cyclization of 5-tetrafluorophenyl-4-ethoxycarbonyl(carboxy)pyrazoles(isoxazoles) produced by the reaction of 3-ethoxycarbonyl-2-methyl- and 3-carboxy-substituted 5,6,7,8-tetrafluorochromones with hydrazine(hydroxylamine). It has been found that 3-ethoxycarbonyl-2-methyl-5,6,7,8-tetrafluorochromone forms the corresponding 2-ethylidenamino-substituted 1,3-keto esters with ammonia and benzylamine, from which 3-ethylidenamino-4-oxy-5,6,7,8-tetrafluorocoumarins were readily obtained. In contrast to the non-fluorinated analogues, 3-ethoxycarbonyl-2-methyl-5,6,7,8-tetrafluorocoumarins were found to undergo acyl-lactone transformation into coumarin structures under acidic conditions.