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Ethyl-4-guaiacol
Guaiacol () is an organic compound with the formula C6H4(OH)(OCH3). It is a phenolic compound containing an methoxy functional group. Guaiacol appears as a viscous colorless oil, although aged or impure samples are often yellowish. It occurs widely in nature and is a common product of the pyrolysis of wood. Occurrence Guaiacol is usually derived from guaiacum or wood creosote. It is produced by a variety of plants. It is also found in essential oils from celery seeds, tobacco leaves, orange leaves, and lemon peels. The pure substance is colorless, but samples become yellow upon exposure to air and light. The compound is present in wood smoke, resulting from the pyrolysis of lignin. The compound contributes to the flavor of many substances such as whiskey and roasted coffee. Preparation The compound was first isolated by Otto Unverdorben in 1826. Guaiacol is produced by methylation of ''o''- catechol, for example using potash and dimethyl sulfate: :C6H4(OH)2 + (CH3O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methoxyphenol
Methoxyphenol or hydroxyanisole may refer to: * 2-Methoxyphenol (guaiacol, ''o''-methoxyphenol, methylcatechol, 2-hydroxyanisole) * 3-Methoxyphenol (''m''-methoxyphenol, ''m''-guaiacol, resorcinol monomethyl ether, 3-hydroxyanisole, ''m''-hydroxyanisole) * 4-Methoxyphenol Mequinol, MeHQ or 4-methoxyphenol, is a phenol used in dermatology and organic chemistry. Uses Dermatology Mequinol is a common active ingredient in topical drugs used for skin depigmentation. As a topical drug mequinol is often mixed with treti ... (mequinol, para-guaiacol, 4-hydroxyanisole) {{Chemistry index Phenol ethers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Unverdorben
Otto Unverdorben (13 October 1806 – 28 November 1873) was a German chemist and merchant who was born in Dahme/Marke. After completing his schooling in Dresden, he studied chemistry at Halle, Leipzig and Berlin. In 1826 at the age of 20, Unverdorben discovered aniline, which he obtained from the distillation of natural vegetable indigo Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m .... He called his discovery ''Crystallin''. Aniline is important in the manufacture of dyes, plastics, and pharmaceuticals. In 1829 he returned to his hometown of Dahme/Mark and became successful in the cigar industry. Today the ''Otto-Unverdorben Dahme-Oberschule'' is named in his honor. References * Biography from the Otto Unverdorben school [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coniferyl Alcohol
Coniferyl alcohol is an organic compound with the formula HO(CH3O)C6H3CH=CHCH2OH. A colourless or white solid, it is one of the monolignols, produced via the phenylpropanoid biochemical pathway. When copolymerized with related aromatic compounds, coniferyl alcohol forms lignin or lignans. Coniferin is a glucoside of coniferyl alcohol. Coniferyl alcohol is an intermediate in biosynthesis of eugenol and of stilbenoids and coumarin. Gum benzoin contains significant amount of coniferyl alcohol and its esters. It is found in both gymnosperm and angiosperm plants. Sinapyl alcohol and paracoumaryl alcohol, the other two lignin monomers, are found in angiosperm plants and grasses. Occurrence Coniferyl alcohol is produced from coniferyl aldehyde by the action of dehydrogenase enzymes. It is a queen retinue pheromone (QRP), a type of honey bee pheromone found in the mandibular glands. In ''Forsythia intermedia'' a dirigent protein was found to direct the stereoselective biosynthesis of (+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propenyl
In organic chemistry, 1-propenyl (or simply propenyl) has the formula CH=CHCH3 and 2-propenyl (isopropenyl) has the formula CH2=C-CH3. These groups are found in many compounds. Propenyl compounds are isomeric with allyl compounds, which have the formula CH2-CH=CH2. Chemicals with 1-propenyl groups * 2-chloropropylene *propenylbenzene (β-methylstyrene). Many phenylpropanoids and their derivatives feature derivatives of propenylbenzene: *Anethole * Asarone * Carpacin *Coniferyl alcohol *Isoeugenol *Isosafrole *Methyl isoeugenol *Pseudoisoeugenol Chemicals with 2-propenyl groups Several terpenes feature 2-propenyl substituents: *carvone *limonene See also * Propene * Functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ... References {{organic-chem-stub Alkenyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosperm
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσπερμος ( el, γυμνός, translit=gymnos, lit=naked, label=none and el, σπέρμα, translit=sperma, lit=seed, label=none), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in yew, ''Torreya'', ''Ginkgo''. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance “lignine”, which is derived from the Latin word '' lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose. Lignin constitutes 30% of non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor of plants and red algae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demethylation
Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms. The counterpart of demethylation is methylation. In biochemistry In biochemical systems, the process of demethylation is catalyzed by demethylases. These enzymes oxidize N-methyl groups, which occur in histones and some forms of DNA: :R2N-CH3 + O → R2N-H + CH2O One such oxidative enzyme family is the cytochrome P450. Alpha-ketoglutarate-dependent hydroxylases are active for demethylation of DNA, operating by a similar pathway. These reactions exploit the weak C-H bond adjacent to amines. In particular, 5-methylcytosines in DNA can be demethylated by TET enzymes as illustrated in the figure. TET enzymes are dioxygenases in the family of alpha-ketoglutarate-dependent hydroxylases. A TET enzyme is an alpha-ketoglut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazonium
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. General properties and reactivity Arenediazonium cations and related species According to X-ray crystallography the linkage is linear in typical diazonium salts. The bond distance in benzenediazonium tetrafluoroborate is 1.083(3) Å, which is almost identical to that for dinitrogen molecule (N≡N). The linear free energy constants σm and σp indicate that the diazonium group is strongly electron-withdrawing. Thus, the diazonio-substituted phenols and benzoic acids have greatly reduced p''K''a values compared to their unsubstituted counterparts. The p''K''a of phenolic proton of 4-hydroxybenzenediazonium is 3.4, versus 9.9 for phenol itself. In other words, the diazonium group lowers the p''K''a (enhances the acidity) by a million-fold. The stabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisole
Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. It is an ether. Anisole is a standard reagent of both practical and pedagogical value. It can be prepared by the Williamson ether synthesis; sodium phenoxide is reacted with a methyl halide to yield anisole. Reactivity Anisole undergoes electrophilic aromatic substitution reaction at a faster speed than benzene, which in turn reacts more quickly than nitrobenzene. The methoxy group is an ortho/para directing group, which means that electrophilic substitution preferentially occurs at these three sites. The enhanced nucleophilicity of anisole vs. benzene reflects the influence of the methoxy group, which renders the ring more electron-rich. The methoxy group str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
O-Anisidine
''o''-Anisidine (2-anisidine) is an organic compound with the formula CH3OC6H4NH2. A colorless liquid, commercial samples can appear yellow owing to air oxidation. It is one of three isomers of the methoxy-containing aniline derivative. Production and use It is prepared via methanolysis of 2-chloronitrobenzene: :NaOCH3 + ClC6H4NO2 → CH3OC6H4NO2 + NaCl The resulting ''o''-nitroanisole is reduced to ''o''-anisidine. ''o''-Anisidine is used in the manufacture of dyes. It is nitrated to give 4-nitroanisidine. It is also a precursor to ''o''-dianisidine. One special use is as a heartwood indicator. An acid solution of ''o''-anisidine is diazotized by adding a sodium nitrite solution. This mixture is applied to the wood and by reaction with polyphenols in the heartwood a reddish brown azo dye is formed. : Safety and environmental aspects ''o''-Anisidine is a dangerous pollutant from the production of dyes. It is listed as RCRA hazardous waste Hazardous waste is w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Sulfate
Dimethyl sulfate (DMS) is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as ( CH3)2 SO4 or Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agent in organic synthesis. Me2SO4 is a colourless oily liquid with a slight onion-like odour (although smelling it would represent significant exposure). Like all strong alkylating agents, Me2SO4 is extremely toxic. Its use as a laboratory reagent has been superseded to some extent by methyl triflate, CF3SO3CH3, the methyl ester of trifluoromethanesulfonic acid. History Dimethyl sulfate was discovered in the early 19th century in an impure form. J. P. Claesson later extensively studied its preparation. It was investigated as a candidate for possible use chemical warfare in World War I in 75% to 25% mixture with methyl chlorosulfonate (CH3ClO3S) called "C-stoff" in Germany, or with chlorosulfonic acid called "Rationite" in France. Product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Sulfate
Dimethyl sulfate (DMS) is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as ( CH3)2 SO4 or Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agent in organic synthesis. Me2SO4 is a colourless oily liquid with a slight onion-like odour (although smelling it would represent significant exposure). Like all strong alkylating agents, Me2SO4 is extremely toxic. Its use as a laboratory reagent has been superseded to some extent by methyl triflate, CF3SO3CH3, the methyl ester of trifluoromethanesulfonic acid. History Dimethyl sulfate was discovered in the early 19th century in an impure form. J. P. Claesson later extensively studied its preparation. It was investigated as a candidate for possible use chemical warfare in World War I in 75% to 25% mixture with methyl chlorosulfonate (CH3ClO3S) called "C-stoff" in Germany, or with chlorosulfonic acid called "Rationite" in France. Product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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