Table 3. Synthesis of Tetrahydrospiro[pyrazolo[3,4-g]quinolines 6(a–e)^a,b.

^aReaction conditions: 5 (1.0 mmol), 2 (1.0 mmol), and 3 (2.0 mmol) in ethanol/water (1:1 v/v) (5 mL) at room temperature (25–30 °C) for—1 h.

^bIsolated yields of the product; the diastereomeric ratio were determined by ¹H NMR analysis.