Pyridine → 5-Chloro-1H-indole-2-carbonyl fluoride

Participants

Reaction Steps

A solution of 5-chloro-1H-indole-2-carboxylic acid (10.0 g, 51.1 mmol) and pyridine (33.1 mmol) in acetonitrile was added to a solution of cyanuric fluoride (2.76 g, 20.4 mmol) in acetonitrile (total 340 mL) at 25° C. The reaction was followed by TLC on aliquots quenched with butylamine and appeared nearly complete at 1 hour. The mixture was poured onto ice, extracted with ether, dried (Na2SO4), and concentrated giving a solid which was used without purification (10.0 g, 99%). TLC of a butylamine-quenched aliquot showed some 5-chloroindole-2-carboxylic acid and the less polar N-butylamide. A sample was purified by chromatography on silica gel eluting with ethyl acetate-hexanes (50-100%) for characterization (16368-130-1).

Provenance & Evidence