3-[2-Chloro-4-(trifluoromethyl)phenoxy]benzoic acid

Step A Extraction of 5-(2-chloro-alpha, alpha, alpha, -trifluoro-4-tolyloxy)-benzoic acid (CTTBA) from the Oxidation Reaction Mass Materials A 1 lb jar of the oxidation mass containing CTTBA was heated in a water bath to 95° C. to melt the contents of the jar. The molten contents were then charged to a 1 liter jacketed reaction vessel fitted with an anchor agitator, thermometer, Dean and Stark system with condenser and a nitrogen purge applied via a bubbler at the top of the condenser. The reactor had been pre-charged with warm water (475 ml at approx. 50° C.) which was agitated during the addition of the molten batch. The product began to solidify and EDC (175 ml) was charged at which point the deposited solid dissolved and partitioned between the two layers. The reactor contents were heated to approx. 77° C. by external water bath circulation (bath at 80° C.) for 30 minutes before stopping the agitation and allowing the reactor contents to separate. The upper aqueous layer was removed by suction and a warm water wash (506 ml) was charged to the reactor, stirred for 30 minutes and then settled before removing the upper aqueous layer as before. The reactor contents were then heated to reflux to remove residual water. After the system had been azeotropically dried a fixed 'balance' charge of EDC was made to dilute the CTTBA in EDC solution to the safe concentration for the following nitration stage.The above-mentioned 3-(2-amino-4-trifluoromethyl)phenoxybenzoic acid wet material was added to 40.5 g of 36percent concentrated hydrochloric acid, stirred, cooled to ° C, and slowly added 30.3 g 0.15m0) sodium nitrite 35percent of the aqueous solution, the temperature control within 5 ° C, after the drip insulation reaction 30min, adding 0.2g copper sulfate, slowly warming to 80-85 ° C, warming to 60 ° C Start dropping 10 g of 36percent concentrated hydrochloric acid, incubating at 80-85 ° C for 1-2 hours, cooling to 50-60 ° C Filtration, washing and drying to give 27.6 g of 98.1percent 3- (2-chloro- 4-trifluoromethyl) phenoxybenzoic acid in a total yield of 81.2percent (m-hydroxybenzoic acid).Acifluorfen A suspension of 40 g of 3-(chloro-4-trifluoromethylphenoxy)benzoic acid in 75 g of propionic acid at 20 C. is admixed with 35.9 g of propionic anhydride. The suspension rapidly becomes a cloudy solution with few solids. Addition of 3.6 g of sulfuric acid is followed by a temperature rise to 36 C. and formation of a dark red-brown solution which is cooled to 1-2 C. Then 8.8 g of concentrated nitric acid are metered in within 2 h and the mixture is stirred for a further 1 h. Then another 0.37 g of nitric acid is added, and the mixture is stirred at 10 C. for 1 h. The reaction mixture is discharged into 194.3 g of boiling water. This forms a brown clear solution which is cooled to 5 C. within 45 minutes. The precipitate is filtered off with suction and washed 3 times with 48.6 g of water. This gives 42.2 g of moist solid, which is converted to 35.4 g of dry solid in a vacuum drying cabinet. Acifluorfen is obtained with 76.1% yield, and contains, for 100 parts of active ingredient, 5 parts of 2-nitro isomer and 0.7 part of 6-nitro isomer.(B) 5-(2-Chloro-4-trifluoromethylphenoxy)-2-nitrobenzoic acid. 3-(2-Chloro-4-trifluoromethylphenoxy)benzoic acid (275.9 g, 0.935 mole), acetic anhydride (276 g, 2.7 mole), glacial acetic acid (276 g, 4.6 mole) and conc. H2 SO4 (44 g) were charged into a three-neck 5 liter flask equipped with a mechanical stirrer, thermometer and an addition funnel. Nitric acid (90percent, 91.7 g, 1.3 mole) was added at 15°-25° C. over 0.5 hr. The cooling bath was substituted with a water bath and the reaction was stirred for 1.5 hrs. at 30° C. The reaction was quenched with 1250 ml of water (at 30° C.), stirred for 0.25 hr. The resultant yellow precipitate was filtered and washed with 2 liters of water. Recrystallization from toluene (750 ml) afforded 271.6 g of 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoic acid; m.p. 120°-121° C.a. Esterification of 3-(2-Chloro-4-trifluoromethylphenoxy)benzoic acid To a 300 ml, 3-necked flask equipped with a stirrer, gas bubbling tube, condenser, thermometer and drying tube is charged anhydrous methanol (100 ml) and METHOD 1 To a flask is charged concentrated sulfuric acid (40 ml) and ethylene dichloride (25 ml), which is then cooled (ice/salt bath) to 0° C. at which tie Method 2 To a 300 ml, 3-necked flask equipped with a condenser, stirrer, drying tube and thermometer is charged dimethylsulfoxide (100 ml), anhydrous potassium carbonate (30 g. >0.20 mole), 3, 4-dichlorobenzotrifluoride (21.5 g., 0.10 mole), pinacol (10 g.) and 3-hydroxybenzoic acid (13.8 g., 0.10 mole). The reaction temperature is then taken slowly to 140°-5° C. while stirring vigorously and maintained as such for 4 days. The reaction mixture is then cooled to room temperature and the inorganic solids removed by filtration prior to pouring the filtrate into water (1200 ml). The aqueous solution is then triturated with CCl4 (2 * 200 ml), decanted and then acidified to pH1 (conc. HCl) to give a tan colored solid, 25, 6 g., mp 114°-17° C. This solid is further purified by dissolving in CCl4 (500 ml) and drying with anhydrous MgSO4. The CCl4 solution is reduced in vacuo to give 19.6 g. (62percent) of a yellow solid, mp 116°-19° C. Recrystallization of the yellow solid from hexane gives a tan colored solid,

Molecular Weight:316.66
XLogP3:4.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:6
Rotatable Bond Count:3
Exact Mass:316.0114063
Monoisotopic Mass:316.0114063
Topological Polar Surface Area:46.5
Heavy Atom Count:21
Complexity:375
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes