18
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Why are lactones more acidic than esters?
Overview
The only interesting thing about lactones is that if the ring size is relatively small, they necessarily adopt the (E) conformation. Therefore, the question essentially boils down to: for a ...
- 71.9k
16
votes
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What is the name origin of ester?
The term "Essigäther" is actually the German name for ethyl acetate i.e Essig = "vinegar" + Äther = "ether". "vinegar" becomes acetic, hence ethyl acetate ...
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11
votes
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Unusual hydrolysis of methyl 2,4,6‐trimethylbenzoate
In the typical reaction of hydroxide ion with a methyl ester, the hydroxide attacks the carbonyl carbon of the ester, resulting ultimately in elimination of methoxide. Given the basic conditions, the ...
- 10.4k
10
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Why are peroxides unstable but disulfide bridges considered stable? Why are esters stable but thiolesters are unstable?
Some hard data: bond enthalpies (in $\pu{kJ mol-1}$)
$$\begin{array}{c|c|c|c} \text{Bond} & \text{Enthalpy} &
\text{Bond} & \text{Enthalpy} \\ \hline
\ce{C-C} & 350 & \ce{Si-...
- 21.9k
10
votes
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On the use of hexane in the organic reduction by DIBAL-H
Unlike other reducing metal hydrides (e.g., $\ce{NaBH4}$ and $\ce{LiAlH4}$), diisobutylaluminum hydride (DIBAL-H) is a liquid at room temperature and dissolve in many hydrocarbons such as toluene and ...
- 42.1k
8
votes
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Are there amide versions of lactides and lactones?
Amide analogue of lactons are lactams, their tautomeric forms are lactims. Citing from the IUPAC Nomenclature of Organic Chemistry (Preferred names 2013):
P-66.1.5.1 Lactams and lactims
...
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8
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Why do amides require much harsher conditions for hydrolysis than esters?
Dimethyl acetamide (DMA) is less susceptible to hydrolysis than ethyl acetate (EA). This statement is true for aqueous acid or base. The infrared (IR) frequency for the carbonyl group of DMA is 1662 ...
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7
votes
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Finding the mystery ester strucuture using NMR
Prediction software always has its limitations, and there is always a degree of error in the calculation. For the ChemDraw predictions, you will see that for the 3 aromatic environments, it has done 3 ...
- 12.1k
7
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Retrosynthesis of a lactone
The key to this synthesis should be — in my opinion — how to generate the two hydroxy functions with anti stereoselectivity starting from at least one achiral reagent. Most of the time you would ...
- 68.7k
7
votes
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Which side of the C-O-C bond breaks in esters during hydrolysis in basic medium?
To answer this,Think about how an ester is formed.
In the formation of an ester, wherin you react an alcohol with an acid in presence of conc.$\ce{H2SO4}$
$\ce{RCOOH + R'OH -> RCOOR' + H2O}$
Now ...
- 1,337
7
votes
Sulphuric Acid in Esterification Reaction
The esterification is not the only thing catalysed by sulphuric acid. Basically, it’s catalytic activity is protonation of whatever feels happy enough to be protonated. In your desired esterification ...
- 68.7k
7
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What happens on heating an ester?
This is an example of a Thermal syn elimination. The Wikipedia article is a good place to start: here
image from here
From ref 2
Unsymmetrical Acetate and xanthate esters yield a mixture of all the ...
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7
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FTIR Spectra: Did I synthesize ethyl gallate from gallic acid?
The short answer: consider a technique complementary to IR spectroscopy, for instance $\ce{^1H}$-NMR spectroscopy.
Your have good luck, as the public AIST spectral database holds records of IR spectra ...
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6
votes
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Why doesn't self condensation occur in acetoacetic ester synthesis
Self-condensation is typically not an issue with 1,3-dicarbonyl compounds, such as the one in your question. Why? Due to their acidity ($\mathrm{p}K_\mathrm{a}$ around 9 to 11), most 1,3-dicarbonyls ...
- 10.8k
6
votes
What is the name origin of ester?
Just to add another resource besides the excellent find by Nilay, in Organic Chemistry, The Name Game, it mentions
ester from German Essigäther (acetic ether) an early name for ethyl
acetate
The ...
- 42.6k
6
votes
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Reaction of methyl triphenylbenzoate with concentrated sulphuric acid
The conditions are concentrated sulfuric acid so there is no water present to hydrolyse the ester. If it was dilute sulfuric then you would get the hydrolysis. This reaction proceeds by protonation of ...
- 22.9k
6
votes
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How to name an ester with an alkene or alkyne as the R group?
According to the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), the names of esters are generally formed by placing the alcoholic ...
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6
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FTIR Spectra: Did I synthesize ethyl gallate from gallic acid?
In determining whether you successfully synthesized ethyl gallate from your gallic acid precursor, let's go over what differences between the two you should expect in your spectra.
Ethyl gallate (...
- 6,802
5
votes
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Residual catalyst leaching from PETE
Let's ignore the safety aspect here, and focus on the 'if i bathe the jug in water so that all the antimony can leach into the water and wash the jug one more time, can all the antimony be removed ...
- 12.1k
5
votes
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Can citric acid create a polyester?
The esterification of carboxylic acids with tertiary alcohols usually occurs by an SN1 mechanism wherein the oxygen of the alcohol is protonated and a tertiary carbocation is formed. It in turn reacts ...
- 17.5k
5
votes
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Naming alkyl groups of an ester
You are going about naming them incorrectly, try breaking it into two parts: the conjugate base of a carboxylic acid and an alkyl group.
$\hspace{5.9cm}$
Combining the two, we get:
$\hspace{6.9cm}$
...
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5
votes
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Which electronic effects are responsible for the reduction of nucleophilicity of a hydroxy group orthogonal to an ester?
If we focus on the 2-oxo-3s-hydroxy-tetrahydrofuran the electronic effects present are the hyperconjugation and the dipole minimization. "Both effects contribute to the preferred (Z)-conformation of ...
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5
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selective hydrolysis problem
If you use methanol as a solvent and add a suitable base, you should end up with the correct product, since any MeOH attacking the protecting group you want to keep will simply re-form the methyl ...
- 17.2k
5
votes
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Is the reaction between a carboxylic acid and alcohol endothermic?
When in doubt, go find data. Here is a typical such reaction - the esterification of ethanol and acetic acid to make ethyl acetate.
$$\ce{CH3CH2OH + CH3CO2H -> CH3CO2CH2CH3 + H2O}$$
The following ...
- 43.2k
5
votes
Retrosynthesis of a lactone
The first idea that comes to mind is an aldol, as you pointed out too:
The only thing left to figure out is what aldol conditions to use to achieve enantioselectivity and the enantioselective ...
- 2,804
5
votes
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Hydrolysis under basic medium
Going by the mechanism of hydrolysis under basic medium, the lone pair of hydroxide ion will attack on C=O carbon.
Due to the negative mesomeric (-M/-R) effect and negative inductive effect of the ...
- 395
5
votes
Naming ester as a substituent to carboxylic acid
As you have correctly stated in the question, the $\ce{-COOH}$ group has higher priority than the $\ce{-COOR}$ group. In fact, the $\ce{-COOH}$ group has the highest priority (excepting cations) in ...
- 2,925
5
votes
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Nitration vs Nitrolysis
Tert-butyl esters are routinely cleaved by anhydrous acid conditions by loss of the tBu+ cation. TFA in DCM is a common system for this. Neat formic acid, HBr/AcOH and PTSA in refluxing benzene or ...
- 22.9k
5
votes
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Synthesis of diethyloxalate from ethene
Conversion 1
Convert ethene to ethanol.
Ethene is mixed with steam and passed over a catalyst consisting of solid silicon dioxide coated with phosphoric(V) acid. The temperature used is 300 °C and ...
- 26.8k
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