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1,2-Cyclopentanedione
1,2-Cyclopentanedione is the organic compound with the formula (CH2)3(CO)2. It is one of two isomeric cyclopentanediones, the other being 1,3-cyclopentanedione. It was first prepared by base-induced condensation of di ethylglutarate with diethyloxalate, followed by hydrolysis of the resulting diketodiester followed by decarboxylation. The enol is predicted to be about 1-3 kcal/mol more stable than the diketo form. The enol structure has been confirmed by X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles .... Structurally related to 1,2-cyclopentanedione is 2-hydroxy-3-methyl-2-cyclopenten-1-one is a flavor additive, also called cyclotene. References {{DEFAULTSORT:Cyclopentanedione, 1, 2- Diketones Cyclic ketones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Hydroxy-3-methyl-2-cyclopenten-1-one
2-Hydroxy-3-methyl-2-cyclopenten-1-one is an organic compound related to 1,2-cyclopentanedione. It is the enol tautomer of the diketone 3-methylcyclopentane-1,2-dione. Being an enol, the compound is often called methylcyclopentenolone. It is a colorless solid. Synthesis and structure The compound is prepared by base-catalyzed condensation of 1‐hydroxyhexane‐2,5‐dione, a derivative of hydroxymethylfurfural. The structure has been confirmed by X-ray crystallography. Quantum calculations also indicate that the enol is strongly favored relative to the diketo tautomer. Furthermore, the enolization occurs at the methyl-substituted carbon. Use and occurrence It is one of many products from the pyrolysis of lignocellulose. It is used in flavors and perfumery for its maple- or caramel-like odor. It contributes to the flavor or odor of many foods including wines, coffee, paprika, and salmon. It is sometimes called maple lactone because it occurs in maple syrup (it is not, ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-Cyclopentanedione
1,3-Cyclopentanedione is an organic compound with the formula (CH2)3(CO)2. It is one of two isomeric cyclopentanediones, the other being 1,2-cyclopentanedione. The enol is predicted to be about 1-3 kcal/mol more stable than the diketo form. The enol structure has been confirmed by X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles .... Preparation The compound is prepared by hydrogenation of 2-cyclopentene-1,4-dione using zinc/acetic acid. References {{DEFAULTSORT:Cyclopentanedione, 1, 3- Diketones Cyclic ketones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diketones
In organic chemistry, a dicarbonyl is a molecule containing two carbonyl () groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls are in close enough proximity that their reactivity is changed, such as 1,2-, 1,3-, and 1,4-dicarbonyls. Their properties often differ from those of monocarbonyls, and so they are usually considered functional groups of their own. These compounds can have symmetrical or unsymmetrical substituents on each carbonyl, and may also be functionally symmetrical (dialdehydes, diketones, diesters, ''etc.'') or unsymmetrical (keto-esters, keto-acids, ''etc.''). 1,2-Dicarbonyls 1,2-Dialdehyde The only 1,2-dialdehyde is glyoxal, . Like many alkyldialdehydes, glyoxal is encountered almost exclusively as its hydrate and oligomers thereof. These derivatives often behave equivalently to the aldehydes since hydration is reversible. Glyoxal condenses re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Oxalate
Dimethyl oxalate is the organic compound with the formula (CO2CH3)2. It is the dimethyl ester of oxalic acid. Dimethyl oxalate is a colorless or white solid that is soluble in water. Production Dimethyl oxalate can be obtained by esterification of oxalic acid with methanol using sulfuric acid as a catalyst: :\rm 2\ CH_3OH + (CO_2H)_2\ \xrightarrow\ (CO_2CH_3)_2 + 2\ H_2O Oxidative carbonylation route The preparation by oxidative carbonylation has attracted interest because it requires only C1 precursors: :\rm 4 \ CH_3OH + 4 \ CO + O_2 \xrightarrow\ 2 \ (CO_2CH_3)_2 + 2 \ H_2O The reaction is catalyzed by Pd2+.E. Amadio''Oxidative Carbonylation of Alkanols Catalyzed by Pd(II)-Phosphine Complexes'' PhD Thesis, Ca’Foscari University Venice, 2009 The synthesis gas is mostly obtained from coal or biomass. The oxidation proceeds via dinitrogen trioxide, which is formed according to (1) of nitrogen monoxide and oxygen and then reacts according to (2) with methanol forming methyl ni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enol
In organic chemistry, alkenols (shortened to enols) are a type of reactive structure or intermediate in organic chemistry that is represented as an alkene ( olefin) with a hydroxyl group attached to one end of the alkene double bond (). The terms ''enol'' and ''alkenol'' are portmanteaus deriving from "-ene"/"alkene" and the "-ol" suffix indicating the hydroxyl group of alcohols, dropping the terminal "-e" of the first term. Generation of enols often involves removal of a hydrogen adjacent (α-) to the carbonyl group—i.e., deprotonation, its removal as a proton, . When this proton is not returned at the end of the stepwise process, the result is an anion termed an enolate (see images at right). The enolate structures shown are schematic; a more modern representation considers the molecular orbitals that are formed and occupied by electrons in the enolate. Similarly, generation of the enol often is accompanied by "trapping" or masking of the hydroxy group as an ether, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
