1571-72-8

beige-grey to brown crystalline powder

3-Amino-4-hydroxybenzoic acid is the first matrix to be used specifically for carbohydrates. The other most commonly used matrices are α-cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid, and sinapinic acid. Matrix and sample solutions are mixed prior to laser exposure, spotted on a solid metallic surface, and allowed to dry before submitting them to MALDI. These matrices are characterized by high absorptivity of the laser radiation and the capability of forming fine crystalline solids during sample/matrix drying. In general, the more fine-grained and homogeneous the morphology of crystals formed with the analyte/matrix mixture, the more intense the MALDI mass spectrum of the analyte. 3-Amino-4-hydroxybenzoic acid produced [M+Na]+ ions from as little as 1 pmol of dextran hydrolysate and N-linked glycans released from glycoproteins.

3-Amino-4-hydroxybenzoic acid is used to produce 4-acetoxy-3-acetylamino-benzoic acid with acetic acid anhydride at temperature of 0 - 20°C. This reaction will need reagents aq. HCl and NaOAc.

ChEBI: A monohydroxybenzoic acid that is 4-hydroxybenzoic acid carrying an additional amino substitutent at position 3.

The Journal of Organic Chemistry, 54, p. 3740, 1989 DOI: 10.1021/jo00276a044

reaction type: solution phase peptide synthesis

The general procedure for the synthesis of 3-amino-4-hydroxybenzoic acid from 4-hydroxy-3-nitrobenzoic acid was as follows: tin(II) chloride (207 mg, 1.09 mmol), 12 N hydrochloric acid (1.5 mL), and 4-hydroxy-3-nitrobenzoic acid (100 mg, 0.55 mmol) were sequentially added to the reaction system at 0 °C. The reaction mixture was heated to reflux for 1 hour. After completion of the reaction, water was added to the mixture and the pH was adjusted to 1 with 2 N sodium hydroxide solution. the precipitate was collected by filtration and washed with distilled water. The filtrate was concentrated under vacuum and methanol was added to the residue. The precipitate formed was filtered again and the filtrate was concentrated under vacuum. Finally, the residue was purified by silica gel column chromatography using dichloromethane and methanol (5:1, v/v) as eluent to afford the target compound 3-amino-4-hydroxybenzoic acid (82 mg, 98% yield) as a brown solid. Its 1H NMR (500 MHz, DMSO-d6) data were as follows: δ 11.30 (brs, 1H), 9.42 (brs, 3H), 7.79 (s, 1H), 7.60 (d, 1H, J = 8.0 Hz), 7.07 (d, 1H, J = 8.0 Hz).

[1] Bioorganic and Medicinal Chemistry Letters, 2018, vol. 28, # 4, p. 684 - 688
[2] Patent: KR2018/117068, 2018, A. Location in patent: Paragraph 0084; 0283; 0286; 0288; 0289
[3] Patent: WO2013/97773, 2013, A1. Location in patent: Paragraph 0267
[4] Chemische Berichte, 1896, vol. 29, p. 1758
[5] Zeitschrift fuer Chemie, 1866, p. 648