Triethylamine → 6-fluoro-1H-indazol-3-yl 4-phenylpiperazine-1-carboxylate

Participants

Reaction Steps

200 mg (1.315 mmol) of 6-fluoro-1H-indazol-3-ol were dissolved in 5 ml of pyridine. Addition of 365 μl (2.63 mmol) of triethylamine and 355 mg (1.56 mmol) of 4-phenyl-piperazine-1-carbonyl chloride was followed by stirring at room temperature for 3 h. Addition of 730 μl of triethylamine and 177 mg of 4-phenylpiperazine-1-carbonyl chloride was followed by stirring for a further 20 h. The reaction mixture was concentrated and mixed with water and ethyl acetate, and the organic phase was separated off, concentrated and purified by preparative HPLC (PR18, acetonitrile/water 0.1% TFA). Yield: 12 mg (2%), M+H+: 529.34, 6-fluoro-1-(4-phenylpiperazine-1-carbonyl)-1H-indazol-3-yl 4-phenylpiperazine-1-carboxylate; 30 mg, (4%), M+H+: 529.40, 6-fluoro-1,2-bis(4-phenylpiperazine-1-carbonyl)-1,2-dihydroindazol-3-one. It was additionally possible to isolate 6-fluoro-1H-indazol-3-yl 4-phenylpiperazine-1-carboxylate as compound not of the invention.

Provenance & Evidence