A facile and consecutive approach to trifluoromethylated spirochromeno[2,3-c]-6H-Pyrazol-2′,5-dione derivatives

•MCRs synthesis of trifluoromethylated spiroheterocycles was described.•A more consecutive approach was achieved.•The p-TSA played dual roles in the conversion.•A plausible reaction mechanism was proposed.

A facile and consecutive one-pot, multi-component reaction for synthesis of trifluoromethylated spirochromeno[2,3-c]-6H-pyrazol-2′,5-dione derivatives by the reaction of isatin, cyclohexane-1,3-dione and 1-aryl-3-(trifluoromethyl)-1H-pyrazol-5(4H)-one in the presence of p- toluenesulfonic acid (p-TSA) with good yields was reported. Compared with the stepwise reactions, the p-TSA played dual roles as both catalyst and dehydrating agent in the conversion. The structures of new compounds were determined by spectroscopic methods and X-ray diffraction analysis. In addition, a possible mechanism for the formation of compound 5 was presented.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideA facile and consecutive one-pot three-component reaction for preparation of trifluoromethylated spirochromeno[2,3-c]−6H-pyrazol-2′,5-dione derivatives in the presence of p-TSA is described.