Trifluoroacetic acid → 6-[(2S,5R)-2,5-dimethylpiperazin-1-yl]-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-b]pyridazine

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Reaction Steps

(2R,5S)-tert-Butyl 2,5-dimethyl-4-[3-(trifluoromethyl)-[1,2,4]triazolo[4,3-b]pyridazin-6-yl]piperazine-1-carboxylate (6.01 g, 15 mmol) was added in portions to stirred TFA (25 mL) over 5 minutes. There was a moderate exotherm and the reaction mixture was allowed to stir for a further 15 minutes. The bulk of the TFA was evaporated and the residue was basified with 1M aqueous K2CO3. It was extracted thoroughly with DCM (4×200 mL) and the combined organic phase was dried over MgSO4 and evaporated to give an oil which rapidly crystallised. The solid was collected by filtration and dried under vacuum to give 6-[(2S,5R)-2,5-dimethylpiperazin-1-yl]-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-b]pyridazine (3.52 g, 78%) as a white crystalline solid.

Provenance & Evidence