The reaction of 2-(1-hydropolyfluoro-1-alkenyl)-4 H-3,1-benzoxin-4-ones with dinucleophilic reagents: a convenient route to fluoroalkylated nitrogen-containing tricyclic compounds

Abstract

The reactions of 2-(1-hydropolyfluoro-1-alkenyl)-4 H-3,1-benzoxin-4-ones ( 2 ) with hydrazine hydrate and phenyl hydrazine were investigated. The reaction of 2 with hydrazine hydrate in ethanol under reflux condition readily gave 2-fluoroalkyl-4 H-pyrazolo[5,1- b]quinazolin-9-ones ( 3 ) in high yields. The reaction of 2 with phenyl hydrazine, however, resulted in the formation of 2-(2-phenyl-5-fluoroalkyl-2 H-pyrazol-3-yl) benzoic acids ( 7 ). Further treatment of 7 with PPA gave 1-phenyl-4,9-dihydro-3-fluoroalkyl-1 H-pyrozolo[3,4- b]quinolin-4-ones ( 4 ) in 65–80% overall yields.