4-Aminobenzoic acid

Chemical Description

4-aminobenzoic acid is a starting material used to synthesize small-molecule mimetics of K5.

Preparation

4-Aminobenzoic acid synthesis method: add 38.0g of p-nitrobenzoic acid, 200mL of water, 20mL of tetrahydrofuran, 0.4g of sodium dodecyl sulfonate and 1.9g of Raney nickel to the autoclave, nitrogen replacement Three times, fill with hydrogen, adjust the pressure to 0.9±0.1MPa, adjust the temperature to 100±2°C, and keep the reaction under pressure for 4h to complete. After the reaction, the catalyst was recovered by filtration, left to stand for stratification, the water layer was directly applied mechanically, the tetrahydrofuran layer was distilled and recovered and applied mechanically, then 1.5 g of activated carbon was added to the 4-aminobenzoic acid mother liquor, and under nitrogen protection, heating and refluxing for decolorization for 20min, Filtration, cooling and crystallization of mother liquor, filtration, drying under vacuum at 80-85 °C to obtain 30.3 g of 4-aminobenzoic acid with a yield of 97.2%, a melting point of 187.1-187.6 °C, and a content of 100.2% (permanent stop titration method) .

Therapeutic Function

Sunscreen agent, Antirickettsial

Biological Functions

4-Aminobenzoic acid is one of the most important aromatic amino acids. It is an important part of the substances necessary for the growth and division of body cells. It has an irreplaceable role in the metabolism of life. It is used in yeast, liver, bran and malt. The content is very high. 4-Aminobenzoic acid can relieve anemia caused by lack of red blood cells, viral anemia, sprue and anemia during pregnancy. 4-Aminobenzoic acid is a high-efficiency nutritional product with the main ingredient - vitamin B-100, which can effectively improve the three major metabolisms of the human body, comprehensively combat fatigue and relieve stress. The compatibility of 4-aminobenzoic acid with penicillin or streptomycin can effectively improve the bacteriostatic effect.

Synthesis Reference(s)

Synthesis, p. 285, 1971Tetrahedron, 47, p. 8587, 1991 DOI: 10.1016/S0040-4020(01)82402-9

Reactivity Profile

4-Aminobenzoic acid is incompatible with ferric salts and oxidizing agents.

Hazard

Questionable carcinogen.

Flammability and Explosibility

Nonflammable

Safety Profile

Moderately toxic by ingestion and intravenous routes. Ingesting large doses can cause nausea, vomiting, skin rash, methemoglobinemia, and possibly toxic hepatitis. Experimental reproductive effects. Mutation data reported. Questionable carcinogen. Combustible. When heated to decomposition it emits toxic fumes of NO,. A topical sunscreen.

Purification Methods

Purify p-aminobenzoic acid by dissolving it in 4-5% aqueous HCl at 50-60o, decolorising with charcoal and carefully precipitating it with 30% Na2CO3 to pH 3.5-4 in the presence of ascorbic acid. It can be recrystallised from water, EtOH or EtOH/water mixtures. [Beilstein 14 IV 1126.]

Industrial Applications

Used as pharmaceutical and dye intermediates, as well as analytical reagents and sunscreen agents. An essential nutrient for many human pathogens but dispensable for humans. It‘s derivatives exhibit various biological activities.

Pharmacological Activities

Exhibits antibacterial, antiviral, and antioxidant activities.
Used in sunscreens to protect against UVB irradiation and as cytoprotective agents and direct anticoagulants.
Shows potential in dermatologic disorders treatment such as scleroderma, dermatomyositis, and Peyronie’s disease.
Promotes resistance against plant bacterial and viral pathogens and has plant growth modulator properties.

Metabolic Pathways

Biosynthesized in organisms from chorismate by a reaction catalyzed by 4-amino-4-deoxychorismate synthase. Metabolized in the liver through N-acetylation or conjugation with glycine to produce 4-aminohippuric acid, which is then excreted in the urine.

Chemical Synthesis

Synthesized from aniline through acylation reaction with acetyl chloride and subsequent reaction with an iodine-containing sodium hydroxide solution. Various methods include esterification reaction, reduction reaction, and acidification reaction.

Definition

ChEBI: 4-aminobenzoic acid is an aminobenzoic acid in which the amino group is para to the carboxy group. It has a role as an Escherichia coli metabolite, a plant metabolite and an allergen. It derives from a benzoic acid. It is a conjugate acid of a 4-aminobenzoate.

Brand name

RVPaba Lipstick (ICN).

General Description

Colorless crystals that discolor on exposure to light and air.