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3,5-dihydroxybenzoic Acid
3,5-Dihydroxybenzoic acid (α-resorcylic acid) is a dihydroxybenzoic acid. It is a colorless solid. Preparation and occurrence It is prepared by disulfonation of benzoic acid followed by hydrolysis of the disulfonate. It is a metabolite of alkylresorcinols, first identified in human urine and can be quantified in urine and plasma, and may be an alternative, equivalent biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ... of whole grain wheat intake. References Dihydroxybenzoic acids Phenolic human metabolites {{phenol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallic Acid
Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. It is a white solid, although samples are typically brown owing to partial oxidation. Salts and esters of gallic acid are termed "gallates". Isolation and derivatives Gallic acid is easily freed from gallotannins by acidic or alkaline hydrolysis. When heated with concentrated sulfuric acid, gallic acid converts to rufigallol. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, respectively. Biosynthesis Gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3,5-didehydroshikimate. This latter compound aromatizes. Reactions Oxidation and oxidative coupling Alkaline solutions of gallic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-Hydroxybenzoic Acid
4-Hydroxybenzoic acid, also known as ''p''-hydroxybenzoic acid (PHBA), is a monohydroxybenzoic acid, a phenolic derivative of benzoic acid. It is a white crystalline solid that is slightly soluble in water and chloroform but more soluble in polar organic solvents such as alcohols and acetone. 4-Hydroxybenzoic acid is primarily known as the basis for the preparation of its esters, known as parabens, which are used as preservatives in cosmetics and some ophthalmic solutions. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin, and with 3-hydroxybenzoic acid. Natural occurrences It is found in plants of the genus ''Vitex'' such as '' V. agnus-castus'' or '' V. negundo'', and in ''Hypericum perforatum'' (St John's wort). It is also found in '' Spongiochloris spongiosa'', a freshwater green alga. The compound is also found in '' Ganoderma lucidum'', a medicinal mushroom with the longest record of use. ''Cryptanaerobacter phenolicus'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloroglucinol
Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isomers are hydroxyquinol (1,2,4-benzenetriol) and pyrogallol (1,2,3-benzenetriol). Phloroglucinol, and its benzenetriol isomers, are still defined as "phenols" according to the IUPAC official nomenclature rules of chemical compounds. Many such monophenolics are often termed "polyphenols" by the cosmetic and parapharmaceutical industries, which does not match the scientifically accepted definition. Synthesis and occurrence In 1855, phloroglucinol was first prepared from phloretin by the Austrian chemist Heinrich Hlasiwetz (1825–1875). A modern synthesis of involves hydrolysis of benzene-1,3,5-triamine and its derivatives. Representative is the following route from trinitrobenzene. : The synthesis is noteworthy because ordinary aniline derivatives are unre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroxybenzoic Acid
Dihydroxybenzoic acids (DHBA) are a type of phenolic acids. There are six main compounds, having all the same molecular formula C7H6O4. Those are: * 2,3-Dihydroxybenzoic acid (2-Pyrocatechuic acid or hypogallic acid) * 2,4-Dihydroxybenzoic acid (β-Resorcylic acid) * 2,5-Dihydroxybenzoic acid (Gentisic acid) * 2,6-Dihydroxybenzoic acid (γ-Resorcylic acid) * 3,4-Dihydroxybenzoic acid (Protocatechuic acid) * 3,5-Dihydroxybenzoic acid 3,5-Dihydroxybenzoic acid (α-resorcylic acid) is a dihydroxybenzoic acid. It is a colorless solid. Preparation and occurrence It is prepared by disulfonation of benzoic acid followed by hydrolysis of the disulfonate. It is a metabolite of alky ... (α-Resorcylic acid) Orsellinic acid is also a dihydoxybenzoic acid having an extra methyl group. {{Chemistry index Dihydroxybenzoic acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonation
Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. Aryl sulfonic acids are used as detergents, dye, and drugs. Stoichiometry and mechanism Typical conditions involve heating the aromatic compound with sulfuric acid: :C6H6 + H2SO4 → C6H5SO3H + H2O Sulfur trioxide or its protonated derivative is the actual electrophile in this electrophilic aromatic substitution. To drive the equilibrium, dehydrating agents such as thionyl chloride can be added. :C6H6 + H2SO4 + SOCl2 → C6H5SO3H + SO2 + 2 HCl Chlorosulfuric acid is also an effective agent: :C6H6 + HSO3Cl → C6H5SO3H + HCl In contrast to aromatic nitration and most other electrophilic aromatic substitutions this reaction is reversible. Sulfonation takes place in concentrated acidic conditions and desulfonation is the mode of action in a dilute hot aqueous acid. The reaction is very useful in protecting the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoic Acid
Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source. Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. Salts of benzoic acid are used as food preservatives. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. The salts and esters of benzoic acid are known as benzoates . History Benzoic acid was discovered in the sixteenth century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and then by Alexius Pedemontanus (1560) and Blaise de Vigenère (1596). Justus von Liebig and Friedrich Wöhler determined the composition of benzoic acid. These latter also investigated how hippuric acid is related ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolite
In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). A primary metabolite is directly involved in normal "growth", development, and reproduction. Ethylene exemplifies a primary metabolite produced large-scale by industrial microbiology. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc. Some antibiotics use primary metabolites as precursors, such as actinomycin, which is created from the primary metabolite tryptophan. Some sugars are metabolites, such as fructose or glucose, which are both p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkylresorcinol
Alkylresorcinols, also known as resorcinolic lipids, are phenolic lipids composed of long aliphatic chains and resorcinol-type phenolic rings. Natural sources of alkylresorcinols Alkylresorcinols are relatively rare in nature, with the main known sources being wheat, rye, barley, triticale (cereal grasses), quinoa, the fruit of ''Ginkgo biloba'' Bilobol, a mollusc and some species of bacteria. DB-2073 is an antibiotic isolated from the broth culture of ''Pseudomonas'' sp. They are also the main constituents of the outer shell of the cyst of ''Azotobacter''. Occurrence in cereals Alkylresorcinols are present in high amounts in the bran layer (e.g. pericarp, testa and aleurone layers) of wheat and rye (0.1-0.3 % of dry weight). 5-Alkylresorcinols can also be found in rice, though not in the edible parts of the rice plant. They are only present in very low amounts in the endosperm (the part of cereal grain that is used to make white flour), which means that alkylresorcinols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. as cited in Biomarkers are used in many scientific fields. Medicine Biomarkers used in the medical field, are a part of a relatively new clinical toolset categorized by their clinical applications. The three main classes are molecular biomarkers, cellular biomarkers or imaging biomarkers. All three types of biomarkers have a clinical role in narrowing or guiding treatment decisions and follow a sub-categorization of being either predictive, prognostic, or diagnostic. Predictive Predictive molecular, cellular, or imaging biomarkers that pass validation can serve as a method of predicting clinical outcomes. Predictive biomarkers are used to help optimize id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroxybenzoic Acids
Dihydroxybenzoic acids (DHBA) are a type of phenolic acids. There are six main compounds, having all the same molecular formula C7H6O4. Those are: * 2,3-Dihydroxybenzoic acid (2-Pyrocatechuic acid or hypogallic acid) * 2,4-Dihydroxybenzoic acid (β-Resorcylic acid) * 2,5-Dihydroxybenzoic acid (Gentisic acid) * 2,6-Dihydroxybenzoic acid (γ-Resorcylic acid) * 3,4-Dihydroxybenzoic acid (Protocatechuic acid) * 3,5-Dihydroxybenzoic acid (α-Resorcylic acid) Orsellinic acid Orsellinic acid, more specifically ''o''-orsellinic acid, is a phenolic acid. It is of importance in the biochemistry of lichens, from which it can be extracted. It is a common subunit of depsides. Chemistry It can be prepared by the oxi ... is also a dihydoxybenzoic acid having an extra methyl group. {{Chemistry index Dihydroxybenzoic acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
