Piperazine → 3-(Piperazin-1-YL)-1H-indazole

Participants

Reaction Conditions

Reaction Steps

A neat mixture of 3-chloroindazole (15.72 g, 0.103 mol) and piperazine (46.00 g, 0.534 mol) was heated at 250° C. for 14 h in a stainless steel sealed vessel Upon cooling to room temperature, the viscous residue was partitioned between 1.0 N aqueous NaOH and methylene chloride. The organic layer was dried over magnesium sulfate, filtered, and the filtrate treated with 4.1 N HCl in dioxane which resulted in the precipitation of both products as a greenish-yellow gummy residue. The gum was collected and taken up in water where it was observed that the disubstituted piperazine precipitated out of solution. The precipitate was filtered off and the filtrate was concentrated in vacuo to give exclusively the monosubstituted piperazine, 3-piperazin-1-yl-1H-indazole, as a green foam. Yield, 19.03 g (77%). MS (APCI): 203 [M+H]+, 201 [M-H]−.

Provenance & Evidence