Fig. 4: Substrate scope of indantriones and aldehydes for producing indenopyrazoles.

a General conditions: (1) In a 25 mL reaction tube, aldehyde 2 (2.1 mmol), p-toluenesulfonyl hydrazide 3 (2.1 mmol), R’OH solvent (20 mL), under ambient atmosphere (1 atm), stirred for 0.5–1 h. (2) indantrione 1a (1.0 mmol), Cs2CO3 (3.0 mmol), at 80 °C for 10 h. b The dr value was determined by 1H-NMR analysis of crude products. c Isolated yield based on 1a.