Novel fluoro-substituted benzo- and benzothieno fused pyrano[2,3-c]pyrazol-4(1H)-ones

A series of mono- and difluoro-substituted chromeno[2,3-c]pyrazol-4(1H)-ones were synthesized in two steps starting from appropriately substituted 2-pyrazolin-5-ones and di- or trifluorobenzoyl chlorides. Detailed NMR spectroscopic investigations (1H, 13C, 15N, 19F) with the obtained compounds were undertaken.