2,3,5,6-Tetrafluorobenzoic acid

white to light yellow crystal powder

50 g (0.258 mol) of 1. At room temperature, 194.1 mg (1.0 mmol) of C0 'was dissolved in 5 mL of SOCl2 and refluxed at 80 CShould 5h, the reaction solution was concentrated under reduced pressure to give a light yellow liquid F ', used directly for the next reactionExample 3 100 g of 2, 3, 5, 6-tetrafluoroterephthalodinitrile were mixed with 140 ml of 70% strength by weight sulfuric acid in an enamelled autoclave and heated for 6 hours at 150 C. 260 ml of water were then added and the mixture was heated for 8 hours at 140 C. After the work-up of the reaction mixture, as specified in Example 1, 78.5 g of 99.5% strength by weight (c) 434 g of 20% strength oleum and 216 g of the product obtained according to (b) were mixed in a glass vessel and heated to the reflux temperature (103 C.) with stirring. When the reflux subsided, the internal temperature was increased slowly to 120 C. After 3 hours, the reaction mixture was cooled to 3 C., and 200 g of ice-water were stirred in with cooling, the temperature being kept below 30 C. The suspension forming was cooled to 3 C., and the precipitate was filtered off, washed with a little ice-water and dried. 166 g of 2, 3, 5, 6-tetrafluoro-benzoic acid having a melting point of 148 C. were obtained, which corresponds to 97% of theory. The purity of the General procedure: Compound 2 (3g, 9.58mmol) was dissolved in anhydrous dichloromethane (30mL), and then trifluoroacetic acid (5mL) was added dropwise under an ice bath. The mixture was stirred overnight at room temperature. After the solvent and trifluoroacetic acid were removed, dissolve the obtained mixture in 50mL dichloromethane and adjust the pH of the solution greater than 7 by dilute ammonia. The organic layer was dried over anhydrous Na2SO4 for 6h, and then concentrated under reduced pressure. The crude product was used without further purifying. Subsequently, dissolve the crude product (1.2 equivalent), Fluorobenzoic acids (FBAs) or benzoic acid (BA) (1 equivalent), 1-hydroxybenzotriazole (HOBt) (1 equivalent) and triethylamine (1 equivalent) in 50mL dichloromethane, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) (1.2 eq.) dissolved in 30mL dichloromethane was added dropwise under an ice bath. The mixture was stirred overnight at room temperature. After the reaction, the solution was washed with saturated NaHCO3 (2×50mL) and brine (50mL). Then the organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (PE: EA=1:1, v/v) to give compound 3a-g.

It is an important intermediate for the preparation of fluoroquinolone antibacterial drugs such as ofloxacin, etc. It can also be used in the preparation of pesticides, liquid crystals, etc.

Molecular Weight:194.08
XLogP3:2
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:6
Rotatable Bond Count:1
Exact Mass:193.99909195
Monoisotopic Mass:193.99909195
Topological Polar Surface Area:37.3
Heavy Atom Count:13
Complexity:197
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes