4-Amino-3-methylbenzoic acid

beige or light buff to orange

To a solution of 3-methyl-4-nitrobenzoic acid (100 g, 552.04 mmol) in methanol (2000 mL) was added Palladium carbon (5.0 g) at room temperature under an atmosphere of hydrogen. After stirring for 24 h at room temperature, the solids were filtered out. The filtrate was concentrated under vacuum to afford 4-amino-3- methylbenzoic acid as a light yellow solid (80 g, 96percent).In a reaction flask equipped with a reflux condenser, a thermometer and a stirrer, 3-methyl-4-nitrobenzoic acid is added36.0 g (0.2 mol) of tetrabutylammonium bromide 0.9 g (0.0028 mol) and 300 ml of water are stirred well, then 16.8 g (0.3 mol) of reduced iron powder, 3.0 g (0.056 mol) of ammonium chloride, and concentrated hydrochloric acid are added. 2 ml, heated to 110°C with stirring, refluxThe reaction was carried out for 2 hours until the reaction of 3-methyl-4-nitrobenzoic acid was complete;Cool down to 35 °C, add sodium carbonate and activated carbon to decolorize for 0.5 hours, add sodium carbonate and activated carbonThe mass of 3-methyl-4-nitrobenzoic acid is 1.5percent and the pH is alkaline. Filtrate iron mud, wash twice with 5percent sodium carbonate solution, mixCombined filter mother liquor and cleaning solution, light yellow solution;Add the above pale yellow solution to sulfuric acid, adjust the pH to slightly acidic, precipitate a white precipitate, filter and wash the filter cake.Two times, the filter cake was vacuum dried in a vacuum oven at 70°C to obtain 27.3 g of 3-methyl-4-aminobenzoic acid.The product obtained in was analyzed by liquid chromatography. The purity of the product was 99.5percent. The melting point analyzer was used to analyze the product.The melting range was 169-172°C, and the molar yield of the product was calculated to be 90.1percent based on the raw material 3-methyl-4-nitrobenzoic acid.In a 1000 ml beaker, 36.2 g (0.2 mol) of 3-methyl-4-nitrobenzoic acid and 300 ml of water were added, and the pH was adjusted with 25percent sodium hydroxide under stirring until the reaction liquid was basic;Then, the above solution was poured into a 1L autoclave, and 3.0 g of Raney nickel catalyst was added. The autoclave was capped with a locking bolt, stirring was started, nitrogen was injected into the autoclave to a pressure of 2.0 MPa, and the nitrogen inlet valve was closed. After 30 minutes, the inside pressure of the autoclave does not decrease, which proves that the autoclave is sealed intact, and each is replaced with nitrogen and hydrogen three times respectively, and the ammonia gas is charged for 2 minutes, and then pressurized with hydrogen to 3.50 MPa, at a pressure of 3.50-2.50 MPa, and a temperature of 140°C. The reaction was performed for about 5 hours until the hydrogen pressure did not decrease any more as the end point of the reaction and the reaction solution was obtained.After the reaction was completed, the temperature was lowered to room temperature, and the catalyst was filtered off. The filtrate was decolored by adding sodium carbonate and activated carbon for 0.5 hour. The amounts of sodium carbonate and activated carbon were respectively 1.5percent of the mass of 3-methyl-4-nitrobenzoic acid, and the activated carbon was filtered out. Sulfuric acid was added to the solution, the pH was adjusted to slightly acidic, a white precipitate was precipitated, and the filter cake was washed with water twice. The filter cake was vacuum dried at 70°C in a vacuum oven to obtain 27.4 g of 3-methyl-4-aminobenzoic acid.FIG. 1 is a nuclear magnetic hydrogen spectrum of 3-methyl-4-aminobenzoic acid prepared in of the present invention.As can be seen from FIG. 1 , 3-methyl-4-aminobenzoic acid was successfully prepared by the present invention.The product obtained in was subjected to liquid chromatography and sample analysis. The purity of the product was 99.5percent. The melting point was analyzed and the melting range of the product was 169-172°C. The molar content was calculated based on the raw material 3-methyl-4-nitrobenzoic acid. The yield was 90.3percent.Example 1a: 4-Amino-3-methyl-benzoic acid EPO

Molecular Weight:151.16
XLogP3:0.8
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:151.063328530
Monoisotopic Mass:151.063328530
Topological Polar Surface Area:63.3
Heavy Atom Count:11
Complexity:158
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes