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The formation of acetals reduces the total number of molecules present (carbonyl + 2 alcohol → acetal + water) and therefore is generally not favourable with regards to entropy. One situation where it is not entropically unfavourable is when a single diol molecule is used rather than two separate alcohol molecules (carbonyl + diol → acetal ...
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, a ketone / ˈ k iː t oʊ n / 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)− (a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' is methyl), with the formula (CH 3) 2 CO ...
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.
Ethylene glycol protects a ketone (as an acetal) during an ester reduction, vs. unprotected reduction to a diol. 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.
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 ...
Acetoacetic ester synthesis is a chemical reaction where ethyl acetoacetate is alkylated at the α-carbon to both carbonyl groups and then converted into a ketone, or more specifically an α-substituted acetone. This is very similar to malonic ester synthesis. Acetoacetic ester synthesis equation
Similarly, 3-ketobutyraldehyde diethyl acetal led to the formation of ethyl 5-methylpyrrole-2-carboxylate. Both of these products resulted from the loss of the acetyl group from the inferred ethyl 2-aminoacetoacetate intermediate.