In organic chemistry, an acetonide is the functional group composed of the cyclic ketal of a diol with acetone. The more systematic name for this structure is an isopropylidene ketal. Acetonide is a common protecting group for 1,2- and 1,3-diols. [1] The protecting group can be removed by hydrolysis of the ketal using dilute aqueous acid.
The acetonides of small di- and triols, as well as many sugars and sugar alcohols, are common. [2] The hexaol mannitol reacts with 2,2-dimethoxypropane to give the bis-acetonide, which oxidizes to give the acetonide of glyceraldehyde: [3] [4]
An example of its use as a protecting group in a complex organic synthesis is the Nicolaou Taxol total synthesis. It is a common protecting group for sugars and sugar alcohols, a simple example being solketal.
The acetonides of corticosteroid are used in dermatology, because their increased lipophilicity leads to better penetration into the skin. [5] [6]
In organic chemistry, a ketone is an organic compound with the structure R−C(=O)−R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group −C(=O)−. The simplest ketone is acetone, with the formula (CH3)2CO. Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids, and the solvent acetone.
In organic chemistry, an acetal is a functional group with the connectivity R2C(OR')2. Here, the R groups can be organic fragments or hydrogen, while the R' groups must be organic fragments not hydrogen. The two R' groups can be equivalent to each other or not. Acetals are formed from and convertible to aldehydes or ketones and have the same oxidation state at the central carbon, but have substantially different chemical stability and reactivity as compared to the analogous carbonyl compounds. The central carbon atom has four bonds to it, and is therefore saturated and has tetrahedral geometry.
Transesterification is the process of exchanging the organic functional group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. Strong acids catalyze the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile. Bases catalyze the reaction by removing a proton from the alcohol, thus making it more nucleophilic. The reaction can also be accomplished with the help of other enzymes, particularly lipases.
Glyceraldehyde (glyceral) is a triose monosaccharide with chemical formula C3H6O3. It is the simplest of all common aldoses. It is a sweet, colorless, crystalline solid that is an intermediate compound in carbohydrate metabolism. The word comes from combining glycerol and aldehyde, as glyceraldehyde is glycerol with one alcohol group oxidized to an aldehyde.
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis.
Oleyl alcohol, or cis-9-octadecen-1-ol, is an unsaturated fatty alcohol with the molecular formula C18H36O or the condensed structural formula CH3(CH2)7−CH=CH−(CH2)8OH. It is a colorless oil, mainly used in cosmetics.
Biphenyl is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one hydrogen may use the prefixes xenyl or diphenylyl.
The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal. It was first reported by Louis Bouveault and Gustave Louis Blanc in 1903. Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol. Modified versions of which were subsequently refined and published in Organic Syntheses.
2,2-Dimethoxypropane (DMP) is an organic compound with the formula (CH3)2C(OCH3)2. A colorless liquid, it is the product of the condensation of acetone and methanol. DMP is used as a water scavenger in water-sensitive reactions. Upon acid-catalyzed reaction, DMP reacts quantitatively with water to form acetone and methanol. This property can be used to accurately determine the amount of water in a sample, alternatively to the Karl Fischer method.
The Danishefsky Taxol total synthesis in organic chemistry is an important third Taxol synthesis published by the group of Samuel Danishefsky in 1996 two years after the first two efforts described in the Holton Taxol total synthesis and the Nicolaou Taxol total synthesis. Combined they provide a good insight in the application of organic chemistry in total synthesis.
Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding four hydrogens. In 2013, its preferred IUPAC name was established as oxane. The compound is a colourless volatile liquid. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and 3,4-dihydropyran are commonly used as protecting groups in organic synthesis. Furthermore, a tetrahydropyran ring system, i.e., five carbon atoms and an oxygen, is the core of pyranose sugars, such as glucose.
Glycol cleavage is a specific type of organic chemistry oxidation. The carbon–carbon bond in a vicinal diol (glycol) is cleaved and instead the two oxygen atoms become double-bonded to their respective carbon atoms. Depending on the substitution pattern in the diol, these carbonyls will be ketones and/or aldehydes.
The Sharpless oxyamination is the chemical reaction that converts an alkene to a vicinal amino alcohol. The reaction is related to the Sharpless dihydroxylation, which converts alkenes to vicinal diols. Vicinal amino-alcohols are important products in organic synthesis and recurring pharmacophores in drug discovery.
The Schotten–Baumann reaction is a method to synthesize amides from amines and acid chlorides:
In organic chemistry, a methoxymethyl ether is a functional group with the formula ROCH2OCH3, abbreviated MOM. It is a kind of chloroalkyl ether and, like its congeners, often employed in organic synthesis to protect alcohols. They are usually derived from 2-methoxymethyl chloride. Closely related to MOM ethers are methoxyethoxymethoxy (MEM) protecting groups, introduced using 2-methoxyethoxymethyl chloride. The MEM protecting groups are more easily installed and more easily removed.
In organic chemistry, the Malaprade reaction or Malaprade oxidation is a glycol cleavage reaction in which a vicinal diol is oxidized by periodic acid or a periodate salt to give the corresponding carbonyl functional groups. The reaction was first reported by Léon Malaprade in 1928. Amino alcohols are also cleaved.
Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate is an anion with chemical formula [{3,5-(CF3)2C6H3}4B]−, which is commonly abbreviated as [BArF4]−, indicating the presence of fluorinated aryl (ArF) groups. It is sometimes referred to as Kobayashi's anion in honour of Hiroshi Kobayashi who led the team that first synthesised it. More commonly it is affectionately nicknamed "BARF." The BARF ion is also abbreviated BArF24−, to distinguish it from the closely related BArF−
20, [(C6F5)4B]−. However, for a small group of chemists, the anion is abbreviated as TFPB otherwise, short for Tetrakis[3,5-bis(triFluoromethyl)Phenyl]Borate.
Diethyl chlorophosphate is an organophosphorus compound with the formula (C2H5O)2P(O)Cl. As a reagent in organic synthesis, it is used to convert alcohols to the corresponding diethylphosphate esters. It is a colorless liquid with a fruity odor. It is a corrosive, and as a cholinesterase inhibitor, highly toxic through dermal absorption. The molecule is tetrahedral.
Isopropenyl acetate is an organic compound, which is the acetate ester of the enol tautomer of acetone. This colorless liquid is significant commercially as the principal precursor to acetylacetone. In organic synthesis, it is used to prepare enol acetates of ketones and acetonides from diols.
In organic chemistry, a benzylidene acetal is the functional group with the structural formula C6H5CH(OR)2 (R = alkyl, aryl). Benzylidene acetals are used as protecting groups in glycochemistry. These compounds can also be oxidized to carboxylic acids in order to open important biological molecules, such as glycosaminoglycans, to other routes of synthesis. They arise from the reaction of a 1,2- or 1,3-diols with benzaldehyde. Other aromatic aldehydes are also used.
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