2'-(Benzyloxy)-2-[4-(tert-butoxycarbonyl)piperazin-1-yl]-4'-fluoroacetophenone → 4-[1-(2-Benzyloxy-4-fluoro-benzoyl)-2-dimethylamino-vinyl]-piperazine-1-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsschritte

A solution of 2′-(benzyloxy)-2-[4-(tert-butoxycarbonyl)piperazin-1-yl]4′-fluoroacetophenone (270 mg, 0.63 mmol) in dimethylformamide dimethylacetal (1.5 mL) was heated in a sealed microwave tube at 200° C. for 15 minutes. A white precipitate formed. The mixture was evaporated to dryness in vacuo to give crude 4-[1-(2-benzyloxy-4-fluoro-benzoyl)-2-dimethylamino-vinyl]-piperazine-1-carboxylic acid tert-butyl ester. Ethanol (2 mL) and hydrazine hydrate (2.0 mL) were added and the mixture heated in a sealed microwave tube at 120° C. for 30 minutes. The crude mixture was loaded onto a dry pre-packed silica cartridge and dried overnight. The product was eluted with 2:1 hexane:EtOAc to give 4-[3-(2-benzyloxy-4-fluoro-phenyl)-1H-pyrazol-4-yl]-piperazine-1-carboxylic acid tert-butyl ester (95 mg, 33%) as a yellow gum; LCMS retention time 2.75 min, M+H+ 453.4.

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