Tetrafluoroboric acid → Methyl 2-chloro-5-fluorobenzoate

Participants

Reaction Steps

A solution of NaNO2 (3.69 g, 53.4 mmol in 50 mL water) was added dropwise to a stirred suspension of methyl 5-amino-2-chlorobenzoate (9 g, 48.5 mmol) in HCl (10%, 90 mL), keeping the temperature between 0-5° C. The reaction mixture was stirred for 10 min. and a solution of fluoroboric acid (70%, excess) was added to the mixture. The precipitate of diazonium fluoroborate salt was filtered, washed with water and dried. The pyrolysis of this salt was then carried out at 140° C. for 15-20 min. The residue was purified using a silica gel column and 10% CHCl3 in petroleum ether (60-80° C.) as an eluant to furnish the title compound.

Provenance & Evidence