Methanesulfonic Acid → 4-Chloro-2-methyl-fluoren-9-one

Participants

Reaction Conditions

Reaction Steps

To a mixture of phosphorus pentoxide (150 g) and methanesulfonic acid (1500 ml) was added 2′-chloro-4′-methyl-biphenyl-2-carboxylic acid (153 g), and the mixture was stirred at 80° C. for 2 hr. The reaction mixture was cooled to 0° C. While keeping the temperature of the reaction mixture at 90° C. or below, water (1500 ml) was added dropwise, and the mixture was further stirred at room temperature for 2 hr. This suspension was filtered, and the obtained solid was washed with water (1000 ml). The solid was suspended in 50 v/v % ethanol-water (1500 ml), and the slurry was stirred at room temperature for 2 hr, and filtered. The obtained solid was air-dried for 1 hr and dried under reduced pressure at 80° C. to give the title compound (140.12 g, 99%).

Provenance & Evidence