2-Chloro-4-fluorobenzoic acid

Powder or crystalline or flakes

2-Chloro-4-fluorobenzoic acid was used in the preparation of 2-(2-chloro-4-fluorophenyl)-benzothiazole.

2-Chloro-4-fluorobenzoic acid can be used as:
(1) Studies on the preparation, luminescence and thermal properties of lanthanide complexes of 2-chloro-4-fluorobenzoic acid.
(2) Preparation, crystal structure, thermal and fluorescence property studies of rare earth complexes composed with 2,2':6′,2″-tripyridine.
(3) Analysis of charge density of intermolecular interactions between isohalogen (Cl--F) and homohalogen (F--F) molecules in molecular crystals. Attractive intermolecular Cl--F interactions (type II interactions) in 2-chloro-4-fluorobenzoic acid.

2-Chloro-4-fluorobenzoic acid is synthesized from m-chloroaniline in four steps. 1) m-Chloroaniline reacts with 2-(trimethylsilyl)ethoxymethyl chloride in the presence of potassium carbonate, potassium iodide, and ionic liquid to give N,N-bis(trimethylsilyl)ethoxymethyl-3-chloroaniline. 2) The product from step 1 reacts with titanium tetrachloride in ionic liquid to yield 4-bis(trimethylsilyl)ethoxymethylamino-2-chlorobenzaldehyde. 3) This aldehyde reacts with hydrogen peroxide and triphenylphosphine rhodium chloride in organic solvent, followed by pressurized hydrogenation with hydrogen. Work-up gives 4-amino-2-chlorobenzoic acid. 4) This acid reacts with hydrogen peroxide in ionic liquid. Potassium fluoride and phosphotungstic heteropoly acid ammonium salt are then added. Work-up yields 2-chloro-4-fluorobenzoic acid.