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Table 1 Optimization of the reaction conditions for the synthesis of 4-(4-chlorophenyl)-3,5-dimethyl-1,4,7,8-tetrahydrodipyrazolo[3,4-b:4′,3′-e]pyridine
figure b

From: Catalyst-free synthesis of tetrahydrodipyrazolopyridines via an one-pot tandem and green pseudo-six-component reaction in water

Entry Solvent Conditionsa Time (min) Yield (%)b
1 EtOH r.t 180
2 EtOH Reflux 120 23
3 H2O Reflux 60 53
4 H2O r.t 45 98 [This work]
  1. aThe molar ratio of hydrazine hydrate (2 mmol), ethyl acetoacetate (2 mmol),4-chlorobenzaldehyde (1 mmol) and ammonium acetate (4 mmol) is equal to 2:2:1:4
  2. bIsolated yields