Search results
Results from the WOW.Com Content Network
Generic structure of acetals. In organic chemistry, an acetal is a functional group with the connectivity R 2 C(OR') 2.Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments not hydrogen.
Acid catalyzed acetal formation from the corresponding hemiacetal. Acetals, as already pointed out, are stable tetrahedral intermediates so they can be used as protective groups in organic synthesis. Acetals are stable under basic conditions, so they can be used to protect ketones from a base. The acetal group is hydrolyzed under acidic conditions.
In organic chemistry, an acetyl group is a functional group denoted by the chemical formula −COCH 3 and the structure −C(=O)−CH 3. It is sometimes represented by the symbol Ac [5] [6] (not to be confused with the element actinium). In IUPAC nomenclature, an acetyl group is called an ethanoyl group.
The inversion of polarity between R'(H)C δ+ =O δ− and R'CLi(SR) 2 is referred to as umpolung. The reaction is commonly performed using the 1,3-dithiane . The lithiated intermediate can be used for various nucleophilic bond-forming reactions, and then the dithioketal hydrolyzed back to its carbonyl form.
Particularly common spiro compounds are ketal (acetal) formed by condensation of cyclic ketones and diols and dithiols. [15] [16] [17] A simple case is the acetal 1,4-dioxaspiro[4.5]decane from cyclohexanone and glycol. Cases of such ketals and dithioketals are common.
The latter reagent in itself is an acetal and therefore the reaction is actually a cross-acetalisation. Kinetic reaction control results from 2-methoxypropene as the reagent. D-ribose in itself is a hemiacetal and in equilibrium with the pyranose 3. In aqueous solution ribose is 75% pyranose and 25% furanose and a different acetal 4 is formed.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Two acetyl-CoA molecules condense to form acetoacetyl-CoA, which gives rise to the formation of acetoacetate and β-hydroxybutyrate. [16] Acetoacetate, β-hydroxybutyrate, and their spontaneous breakdown product acetone [ 18 ] are frequently, but confusingly, known as ketone bodies (as they are not "bodies" at all, but water-soluble chemical ...