4- Amino-3-hydroxybenzoic acid

By feeding [7- C]3-amino -hydroxybenzoic acid (3,4-AHBA) 242 to liquid cultures of S. nodosus ssp. asukaensis ATCC 29757 and also to S. parvulus Tii 64, intact incorporation of 242 into the manumycins was observed, which showed that 3,4-AHBA indeed serves as the polyketide starter unit for the formation of the lowei chain. 

Mesalamine. Rowasa, Asacol, and Pentasa are trade names for mesalamine [89-57-6] (5-ASA, 5-amino-2-hydroxybenzoic acid). It is a white to pinkish crystalline substance that is slightly soluble in cold water and alcohol, more soluble in hot water, and soluble in hydrochloric acid. It may be prepared by the reduction of y -nitrobenzoic acid with zinc dust and HCl. 

Amino-2-hydroxybenZOiC acid. This derivative (18) more commonly known as 4-aminosa1icy1ic acid, forms white crystals from ethanol, melts with effervescence and darkens on exposure to light and air. A reddish-brown crystalline powder is obtained on recrystallization from ethanol —diethyl ether. The compound is soluble ia dilute solutioas of nitric acid and sodium hydroxide, ethanol, and acetone slightly soluble in water and diethyl ether and virtually insoluble in benzene, chloroform or carbon tetrachloride. It is unstable in aqueous solution and decarboxylates to form 3-amiaophenol. Because of the instabihty of the free acid, it is usually prepared as the hydrochloride salt, mp 224 °C (dec), dissociation constant p 3.25. 

Amino-2-hydroxybenzoic acid is manufactured by carboxylation of 3-amiaophenol under pressure with ammonium carbonate at 110 °C (182) or with potassium bicarbonate and carbon dioxide at 85—90°C (183) with subsequent acidification. 

The ansa-chain of the ansamycins streptovaricins (4), rifamycins (263), geldanamycin (4), and herbimycin (32) has been shown to be polyketide in origin, being made up of propionate and acetate units with the 0-methyl groups coming from methionine. The remaining aromatic C N portion of the ansamacroHdes is derived from 3-amino-5-hydroxybenzoic acid (264—266) which is formed via shikimate precursors. Based on the precursors of the rifamycins and streptovaricins isolated from mutant bacteria strains, a detailed scheme for the biosynthesis of most of the ansamacroHdes has been proposed (95,263). 

Aminosalicylic acid (5-amino-2-hydroxybenzoic acid) [89-57-6] M 153.1, m 276-280 , 283 (dec), pK 2.74 (CO2H), pK 5.84 (NH2). Cryst as needles from H2O containing a little NaHS03 to avoid aerial oxidation to the quinone-imine. The Me ester gives needles from C6H6, m 96°, and the hydrazide has m 180-182° (From H2O). [Fallab et al. Helv Chim Acta 34 26 1951, Shavel J Amer Pharm Assoc 42 402 1953.]... 

Chemical Name 4-amino-2-hydroxybenzoic acid Common Name —... 

Therapeutic Function Antibacterial (Tuberculostatic) Chemical Name 4-Amino-2-hydroxybenzoic acid phenyl ester Common Name Fenamisal Structural Formula cc... 

Figure 11.5 3-Amino-5-hydroxybenzoic acid as a precursor to the porfiromycin C quinone. 

Figure 11.6 The aminoshikimate pathway to 3-amino-5-hydroxybenzoic acid.

CN 5 [[4-[[(2-carboxyethyl)amino]carbonyl]phenyl]azo]-2-hydroxybenzoic acid disodium salt ( )-free acid... 

Replacement of the hydroxyl group on the phenyl ring with a carboxyl group forms a molecule of benzoic acid. Addition of a hydroxyl at the 2-position on a benzoic acid molecule forms 2-hydroxybenzoic acid or salicylic acid. The slightly more complex phenylpropanoid skeleton contains a linear three-carbon chain (the propanoic group) added to the benzene ring (the phenyl group). Addition of ammonia to carbon 2 of this three-carbon side chain yields the amino acid phenylalanine (Fig. 3.3). Phenylalanine... 

The choice of a matrix tailored for a particular kind of polymer sample is cmcial for successful characterization of the sample. Therefore, it is useful to discuss the properties of some common matrices [4—6], 3-Amino-4-hydroxybenzoic acid and POPOP need high laser power, since they possess a high threshold. Alpha-cyanocynnamic acid is... 

Amino-2-hydroxybenzoic acid, 2 668-669 physical properties of, 2 666t 2-Amino-2-(hydroxymethyl)-1,3-propanediol... 

The mixed anhydride method was used with diaminoethane to give a free amino group that was subsequently reacted with 4-hydroxybenzoic acid to provide an aromatic ring to allow iodination with [ ] to increase sensitivity of the assay compared with labelled radioactive tracers. This reaction could also be used to prepare fluorescent compounds for cell-biology studies. 

The shikimate pathway was identified through the study of ultraviolet light-induced mutants of E. coli, Aerobacter aerogenes, and Neurospora. In 1950, using the penicillin enrichment technique (Chapter 26), Davis obtained a series of mutants of E. coli that would not grow without the addition of aromatic substances.4 5 A number of the mutants required five compounds tyrosine, phenylalanine, tryptophan, p-aminobenzoic acid, and a trace of p-hydroxybenzoic acid. It was a surprise to find that the requirements for all five compounds could be met by the addition of shikimic acid, an aliphatic compound that was then regarded as a rare plant acid. Thus, shikimate was implicated as an intermediate in the biosynthesis of the three aromatic amino acids and of other essential aromatic substances.6 7... 

The method is often important in the preparation of hydroxy derivatives of compounds the groups in which render them difficult to prepare by more direct means. m-Hydroxybenzoic acid is such a compound. It is obtained by nitration of benzoic acid followed by reduction to m-amino-benzoic and application of the present reaction (see below). 

Kim C-G, Kirschning A, Bergon P, Zhou P, Su E, Sauerbrei B, Ning S, Ahn Y, Breuer M, Leistner E, Floss HG (1996) Biosynthesis of 3 -Amino-5 -hydroxybenzoic Acid, the Precursor of mCyN Units in Ansamycin Antibiotics. J Am Chem Soc 118 7486... 

Amino-4-hydroxybenzoic acid First matrix to be developed specifically for carbohydrates (free glycans) found to be useful for the analysis of glycoprotein A-glycans31... 

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