2251-54-9Relevant academic research and scientific papers
Process improvements in the synthesis of 2,4,5-trifluorobenzoic acid. selective hydrodefluorination of tetrafluorophthalimides
Fertel, Lawrence B.
, p. 111 - 115 (2013/09/08)
An improved preparation of the fluoroquinolone antibacterial intermediate 2,4,5-trifluorobenzoic acid is described. A combination of a selective hydrodefluorination and hydrolysis reaction of 3,4,5,6-tetrafluoro-N-methylphthalimide leading to 3,5,6-trifluorophthalic acid was key to the success of the process. In addition the development of a two-step, one-pot imidization/ halogen exchange from tetrachlorophthalic anhydride to 3,4,5,6-tetrafluoro-N-methylphthalimide in sulfolane solvent is detailed.
Process for the preparation of salts of substituted or unsubstituted phthalic acids
-
, (2008/06/13)
The present invention relates to a process for the preparation of salts of substituted or unsubstituted phthalic acids, by reacting a compound of the formula STR1 in which R1, R2, R3 and R4 are identical or different and are H, F, Cl, Br, CF3, OH, an alkoxy or alkyl radical in each case having 1 to 4 carbon atoms, or a radical --NR7 R8, in which R7 and R8 are identical or different and are H, an alkyl radical having 1 to 4 carbon atoms, or a phenyl radical, R5 and R6 are identical or different and are H, a --CO-- alkyl group having 1 to 6 carbon atoms in the alkyl radical, or a benzoyl group, or R5 and R6 together form a radical of the formula STR2 in which R9, R10, R11 and R12 are identical or different and are H, F, Cl, Br, CF3, OH, an alkoxy or alkyl radical in each case having 1 to 4 carbon atoms, or a radical --NR7 R8, in which R7 and R8 are identical or different and are H, an alkyl radical having 1 to 4 carbon atoms, or a phenyl radical, with water, a water-soluble base, and an oxidizing agent at a temperature of -10° to 150° C. in the presence or absence of a water-insoluble solvent inert under the reaction conditions.
Preparation of 3,4,6-trifluorophthalic acid
-
, (2008/06/13)
3,4,6-trifluorophthalic acid is prepared in high yield by reaction of a 3,4,6-trichloro-N-substituted phthalimide with potassium fluoride at temperatures in the range of 200° to 270° C. in the absence of a catalyst to form the corresponding trifluoro-N-su
Process for the preparation of 3,4,6-trifluorophthalic acid and the anhydride thereof
-
, (2008/06/13)
Process for the preparation of 3,4,6-tetrafluorophthalic acid of the formula (1) STR1 or the anhydride thereof in good yields and in an advantageous manner, by dehalogenating tetrafluorophthalic anhydride of the formula (2) STR2 or tetrafluorophthalic aci
Tetrafluoro-N-phenylphthalimide
-
, (2008/06/13)
Chlorinated phthalic anhydrides are converted to fluorinated phthalic acids without dilactone formation by reacting an anhydride with a primary amine under anhydrous conditions to form the corresponding chlorinated-N-substituted phthalimide which in turn is reacted with a fluorinating agent under anhydrous conditions to form the corresponding fluorinated phthalimide which is hydrolyzed to form the corresponding fluorinated phthalic acid. In a preferred embodiment tetrachlorophthalic anhydride is refluxed with aniline in the presence of glacial acetic acid for 5 to 10 hours to form tetrachloro-N-phenylphthalimide which is reacted with KF in sulfolane in the presence of tributylhexadecylophosphonium bromide under nitrogen at 140° C. to 160° C. for 10 to 15 hours to form tetrafluoro-N-phenylphthalimide which in turn is hydrolyzed by refluxing with 50% H2 SO4 for 15 to 25 hours. The tetrafluoro-N-phenylphthalimide is a novel compound. The fluorinated phthalic acid products are intermediates for the corresponding fluorinated phthalic anhydrides, fluorinated benzoic acids and fluorinated benzenes.
