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Aldol
In organic chemistry, an aldol describes a structural motif consisting of a 3-hydroxy ketone or 3-hydroxyaldehyde. Aldols are usually the product of aldol addition. When used alone, the term "aldol" may refer to 3-hydroxybutanal. Stereochemistry Despite having only two functional groups, many aldols can have complicated structures arising from the relative positions of the OH group and the substituent between it and the carbonyl. Controlling reactions in order to favor the formation of one of these isomers is of great interest in the area of asymmetric synthesis. Reactions The chemistry of aldols is dominated by one reaction, dehydration: :RC(O)CH2CH(OH)R' → RC(O)CH=CHR' + H2O Hydroxypivaldehyde Hydroxypivaldehyde is the organic compound with the formula HOCH2(CH3)2CCHO. A colorless liquid, it is produced by condensation of formaldehyde and isobutyraldehyde: :CH2O + (CH3)2CHCHO → HOCH2(CH3)2CCHO The compound is a rare example of a ... is a rare example of a rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldol Reaction
The aldol reaction is a means of forming carbon–carbon bonds in organic chemistry. Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles-Adolphe Wurtz in 1872, the reaction combines two carbonyl compounds (the original experiments used aldehydes) to form a new β-hydroxy carbonyl compound. These products are known as ''aldols'', from the ''ald''ehyde + alcoh''ol'', a structural motif seen in many of the products. Aldol structural units are found in many important molecules, whether naturally occurring or synthetic. For example, the aldol reaction has been used in the large-scale production of the commodity chemical pentaerythritol and the synthesis of the heart disease drug Lipitor (atorvastatin, calcium salt). The aldol reaction unites two relatively simple molecules into a more complex one. Increased complexity arises because up to two new stereogenic centers (on the Alpha carbon, α- and β-carbon of the aldol adduct, mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldol2
In organic chemistry, an aldol describes a structural motif consisting of a 3-hydroxy ketone or 3-hydroxyaldehyde. Aldols are usually the product of aldol addition. When used alone, the term "aldol" may refer to 3-hydroxybutanal. Stereochemistry Despite having only two functional groups, many aldols can have complicated structures arising from the relative positions of the OH group and the substituent between it and the carbonyl. Controlling reactions in order to favor the formation of one of these isomers is of great interest in the area of asymmetric synthesis. Reactions The chemistry of aldols is dominated by one reaction, dehydration: :RC(O)CH2CH(OH)R' → RC(O)CH=CHR' + H2O Hydroxypivaldehyde Hydroxypivaldehyde is the organic compound with the formula HOCH2(CH3)2CCHO. A colorless liquid, it is produced by condensation of formaldehyde and isobutyraldehyde: :CH2O + (CH3)2CHCHO → HOCH2(CH3)2CCHO The compound is a rare example of a ... is a rare example of a rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are common and play important roles in the technology and biological spheres. Structure and bonding Aldehydes feature a carbon center that is connected by a double bond to oxygen and a single bond to hydrogen and single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The C=O bond length is about 120-122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes are more soluble in water, formaldehyde and acetaldehyde completely so. The volatile aldehydes have pungent odors. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-hydroxybutanal
3-Hydroxybutanal (acetaldol) is an organic compound with the formula CH3CH(OH)CH2CHO. It is classified as an aldol, formally the product of the dimerization of acetaldehyde. A colorless liquid, it is a versatile and valuable intermediate with diverse impacts. The compound is chiral although this aspect is not often exploited. Production Acetaldehyde dimerizes upon treatment with aqueous sodium hydroxide: :2CH3CHO → CH3CH(OH)CH2CHO + H2O Reactions and uses Dehydration of 3-hydroxybutanal gives crotonaldehyde. Distillation of 3-hydroxybutanal is sufficiently forcing to effect this conversion: :CH3CH(OH)CH2CHO → CH3CH=CHCHO + H2O Hydrogenation of 3-hydroxybutanal gives 1,3-butanediol: :CH3CH(OH)CH2CHO + H2 → CH3CH(OH)CH2CH2OH This diol is a precursor to 1,3-butadiene, precursor to diverse polymers. Polymerization of 3-hydroxybutanal is also spontaneous, but can be stopped with the addition of water. Former or niche uses It was formerly used in medicine as a hypno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehydes
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are common and play important roles in the technology and biological spheres. Structure and bonding Aldehydes feature a carbon center that is connected by a double bond to oxygen and a single bond to hydrogen and single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The C=O bond length is about 120-122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes are more soluble in water, formaldehyde and acetaldehyde completely so. The volatile aldehydes have pungent odors. Aldehy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxypivaldehyde
Hydroxypivaldehyde is the organic compound with the formula HOCH2(CH3)2CCHO. A colorless liquid, it is produced by condensation of formaldehyde and isobutyraldehyde: :CH2O + (CH3)2CHCHO → HOCH2(CH3)2CCHO The compound is a rare example of a distillable aldol (3-hydroxyaldehyde). Upon standing, it dimerizes reversibly to the dioxane derivative. Its main use, in terms of scale, is as a precursor to neopentyl glycol Neopentyl glycol (IUPAC name: 2,2-dimethylpropane-1,3-diol) is an organic chemical compound. It is used in the synthesis of polyesters, paints, lubricants, and plasticizers. When used in the manufacture of polyesters, it enhances the stability of ...: :HOCH2(CH3)2CCHO + H2 → (CH3)2C(CH2OH)2 It is also used in the industrial synthesis of vitamin B5.{{cite journal , doi=10.1002/anie.201205886 , title=One Hundred Years of Vitamins-A Success Story of the Natural Sciences , year=2012 , last1=Eggersdorfer , first1=Manfred , last2=Laudert , first2=Dietmar , las ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (included in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxy Ketone
In organic chemistry a hydroxy ketone (often referred to simply as a ketol) is a functional group consisting of a ketone flanked by a hydroxyl group. In the two main classes, the hydroxyl group can be placed in the alpha position (an alpha-hydroxy ketone RCR′(OH)(CO)R) or in the beta position (a beta-hydroxy ketone, RCR′(OH)CR2(CO)R). * An α-hydroxy ketone can consist of either a primary alcohol (e.g. hydroxyacetone) or a secondary alcohol; the latter are often broadly referred to as acyloins * Prominent β-hydroxy ketones are aldol adducts. * Only terminal α-hydroxy ketones can give positive Fehling's test In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone () functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' r .... References {{chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Synthesis
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer. Enantiomers are stereoisomers that have opposite configurations at every chiral center. Diastereomers are stereoisomers that differ at one or more chiral centers. Enantioselective synthesis is a key process in modern chemistry and is particularly important in the field of pharmaceuticals, as the different enantiomers or diastereomers of a molecule often have different biological activity. Overview Many of the building blocks of biological systems such as sugars and amino acids are produced exclusively as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
