Questions tagged [carbonyl-compounds]

For questions about compounds containing the carbonyl group, C=O, the carboxylic acid group (-COOH), or its derivatives (anhydrides/esters/amides/acid halides). For questions about complexes involving carbon monoxide as a ligand use [carbonyl-complexes] instead.

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Sulfonyl azides: diazo or azide transfer?

Sulfonyl azides, $\ce{RSO2N3}$, are capable of acting as sources of electrophilic azide ("$\ce{N+3}$"), but are also capable of effecting diazo transfer, as shown in the scheme below, taken from ref 1:...
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1answer
3k views

Reaction of glucose with 2,4-dinitrophenylhydrazine (DNPH)

In its open-chain form, glucose possesses an aldehyde group; however, glucose does not test positive with 2,4-dinitrophenylhydrazine (which typically forms a yellow/orange/red precipitate with ...
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How can I solve this synthesis?

I have this task to do: My solution: Is that possible? Can you please help me with the steps 2 and 3? This is what I did, but my teacher told me I should make the diketone (compound no. 5) from ...
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What can we say about the dipole moment of terephthalic acid?

The dipole moment of quinol is not zero because it can exist in two different energetically favourable conformations. The weighted average is calculated to arrive a dipole moment of 1.6 D. According ...
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2answers
7k views

Why does adipic acid give a cyclic ketone on heating while glutaric acid and succinic acid give a cyclic anhydride?

Why does adipic acid give cyclic ketone on heating while glutaric and succinic acid give cyclic anhydride?
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53 views

Can a per-acetylated sugar anomerize?

So I have a question concerning a reaction mechanism for the reaction below. I know for certain that I get the alfa anomer, but I can't explain it. When I draw out the mechanism it doesn't make sense ...
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230 views

pKa of different sites of butanone

From what I can tell, deprotonation of the central hydrogen leads to the more thermodynamically stable product (most substituted double bond. i.e. most stabilization by hyperconjugation). Therefore, ...
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236 views

Stability of extended enolates

I'd expect an extended enolate to be more stable than a normal enolate, when both can form, but my textbook suggests otherwise. What is the stability of an extended enolate compared with a normal ...
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414 views

Why does the keto tautomer of guanine have lower energy?

Looking at the keto and enol forms of guanine, it would seem as if the enol form is more stable, due to the fact that aromaticity is established with the enol form. However, according to a question on ...
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1answer
3k views

Protonation of Carbonyl oxygen in Fischer Esterification

In the Fischer Esterification, why is it the acid's carbonyl oxygen getting protonated and not the hydroxyl oxygen? This protonation occurs in Step 1 of the mechanism below. I read in some textbooks ...
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106 views

Reagents for synthesis of ethyl 2-(2,3-dihydrobenzofuran-2-yl)acetate from naphthalen-1(4H)-one

The following conversion can be performed in a few steps. Show key intermediates and reagents (detailed mechanisms are not required). So I've been looking at this for a while and I can't seem ...
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66 views

An unconventional decarboxylation to form bullatenone

I recently had an assessment which required me to draw the mechanism of decarboxylation of a $\beta$-ketoacid. However, it is slightly peculiar because there is the presence of $\alpha$, $\beta$-...
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261 views

Reaction of alpha hydroxyketone with KOH

What happens when 2-hydroxycyclohexan-1-one (an alpha hydroxyketone) reacts with aqueous $\ce{KOH}$? I tried something like Favorskii rearrangement, but it's wrong because OH isn't a good enough ...
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319 views

Regioselectivity of the Beckmann rearrangement

It seems to be that the Beckmann rearrangement is a nice way to prepare secondary amines. This can be achieved by removal of oxygen via the use of $\ce{HI}$/$\ce{P}$. However, if ketones are used, ...
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1answer
598 views

Does acid anhydride give a positive iodoform test?

I thought that acetic anhydride $\ce{CH3COOCOCH3}$ would give a positive Iodoform test because it has a $\ce{CH3-(CO)}-$ group.But it is given that this does not happen. Is this true? If so, can ...
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257 views

Does alcohol hydrogen in the enol tautomer of a β-dicarbonyl have sp² character?

My reasoning for the somewhat implausible "$\mathrm{sp^2}$" character of the hydrogen between these two oxygens on the enol structure of the right comes from recognizing that if it were, then we would ...
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267 views

What is the average chain length of a glutaraldehyde crosslink between primary amines?

Imagine I'm performing a primary amine to primary amine (i.e. PA to PA) crosslinking reaction at $37~^{\circ}\mathrm{C}$ in phosphate-buffered saline (pH $\approx 7.4$) with glutaraldehyde drawn from ...
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1answer
1k views

Why are acid catalysed reactions of carbonyl compounds reversible?

I am currently studying aldehydes and ketones and their reactions. I've noticed that acid catalysed reactions are represented with reversible arrows, while base catalysed reactions are shown with ...
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58 views

How does a cyclization occur with a carboxylic acid and (CF3CO)2O?

The product of the reaction below is unsaturated, bicyclic ketone, but I'm confused as to how (CF3CO)2O reacts with it to cause the cyclization. There is no base involved so I don't know how the ...
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Will phosphorous Ylide participate in carbene generation and insertion?

The following question was sent to me . The answer for this question was given to me as option b I attempted it as following , recognizing the first step as a ylide reaction with a carbonyl compound....
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1answer
182 views

Specific reduction of certain functional groups

Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$. For example consider- Now consider the operations: $\ce{1. (A) + (i)BH3/THF (ii) H+}$ $\ce{2. (A) + H2/Pt}$ ...
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94 views

Claisen-like condensation with acid chloride

In the Claisen condensation, an ester enolate attacks an ester, with an alkoxide anion leaving subsequently to give a $\beta$-keto ester. Is it possible for a typical enolate of an aldehyde or ketone ...
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542 views

Why does the proton transfer from the oxygen to the nitrogen atom in imine formation not occur through an intramolecular process?

In my book Organic Chemistry by David Klein, 2nd edition, the book shows that the oxygen atom first takes a proton from an acid, then, the conjugate base of the acid takes a proton from the nitrogen ...
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1k views

Which enolate of butanone is more stable?

Consider butanone (A) and its two possible enolates B & C. Which of the two enolates will be more stable? B because of the more stable primary carbanion, or C because of more stable enolate (...
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99 views

How can the ketone in a β-ketoester be protected during hydride reduction?

I am supposed to find what X is. I know that $\ce{LiAlH_4}$ will convert all carbonyl groups to alcohols, and the ester group is being reduced. The only way of ending up with a ketone that I can think ...
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1k views

Why do electronegative heteroatoms increase C=O stretching frequency (bond strength)

Why does a more electronegative heteroatom (i.e. $\ce{Cl}$ or $\ce{O}$) increase the stretching frequency of a carbonyl? I'd suspect it's that they donate their lone pairs and we end up with a ...
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1answer
540 views

Mechanism for conversion of imide to ester with NaH

What is the mechanism of this reaction? My proposed mechanism is shown below, would it work?
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57 views

Why aren't nitriles very good electrophiles?

I was wondering why nitriles do not react as electrophiles like carbonyl unless they have to, given that the C-N triple bond is still pretty polarized. The LUMO will be higher in energy than a ...
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35 views

Why doesn't HIO4 cleave acetals?

Recently, I started reading about the cleavage reactions done by $\ce{HIO4}$.I came across a statement which read $\ce{HIO4}$ can't cleave acetals but it can cleave hemiacetals. But when I tried to ...
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63 views

What is the product of following iodoform reaction?

Question Attempt I think the product A would be as I have attempted below, but I am getting the answer as A but book says D. Where am I wrong? Please help.
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50 views

Bond strength of carbon compounds

I read online that C=O is more stronger than C=N and the reason behind this was, 'Since bond between C and O is more polar hence it will have a slightly higher ionic nature than C and N. As we know ...
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44 views

Steric inhibition of resonance in substituted benzoic acid

Why does attaching an $\ce{-NO2}$ group at the ortho position of benzoic acid cause $\ce{-COOH}$ to become perpendicular to the plane of the benzene ring? Why doesn't the nitro group get pushed out ...
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59 views

Reaction of diamines with carboxylic acids to form imidazole

I've recently came across this reaction and my guess is that firstly an amide forms that later reacts with the second amine group. Is this a general reaction? Does it matter if the compounds used are ...
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131 views

The use of silyl enol ethers over aza-enolates

I do not quite understand how alkylations using tertiary halides would work better with silyl enol ethers, compared with using the aza-enolate nucleophile. The following was mentioned in Clayden, ...
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42 views

What takes place in this transformation of the 1,3-dicarbonyl?

I was just looking at a particular synthesis method on the Organic Chemistry Portal when I saw a particularly puzzling step, involving a 1,3-dicarbonyl compound. The step which I am puzzled by is ...
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139 views

Why does gilman reagent react with acyl chlorides but not with other carbonyls?

According to HSAB (hard-soft acid-base) concept, a soft nucleophile preferentially reacts with soft electrophile and a hard nucleophile with a hard electrophile. Since $\ce {R2CuLi}$ is a soft ...
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901 views

Effect of H-bonding on o-nitrobenzoic acid

My argument here is regarding the acidity of o-nitrobenzoic acid being greater than p,m-nitrobenzoic acid. In o-nitrobenzoic acid, there is an intramolecular hydrogen bond which makes the bond ...
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65 views

How would one disassociate the carboxylic acid on the end of a perfluorooctanoic acid molecule?

This is what a perfluorooctanoic acid molecule looks like. The carboxylate head on the end would normally disassociate in water because carboxylic acids are weak, but because of the fluorocarbon tail, ...
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53 views

Reactivity of carbonyl adjacent to cyclopropyl group

We know that cyclopropyl, because of $\ce{sp^{\sim 5}}$, hybrid orbitals behaves much like a double bond. It even takes part in conjugation to stabilise positive charge on carbons adjacent to it. I ...
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87 views

Can an enol acetate be formed through Fischer esterification?

Since acetone is converted into its enol form under acidic conditions, could it participate in Fischer esterification to form an enol acetate? For example, would refluxing acetone, p-TSA, and acetic ...
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2k views

Reactions of Grignard Reagents with amides

Can Grignard reagents add to amides? It appears from the synthetic pathway shown below that there has been some form of nucleophilic substitution at the carbonyl group. Source: 49th IChO Preparatory ...
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What is the reason for colour in 2,4-Dinitrophenylhydrazine derivatives?

2,4-Dinitrophenylhydrazine is an important laboratory reagent for the detection of Carbonyl (C=O) group. It reacts with Carbonyl group by the typical Nucleophilic Addition-Elimination reaction and if ...
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824 views

Decarboxylation mechanism and stability of α,β-unsaturated and α-hydroxy acids

I was wondering why α,β-unsaturated and α-hydroxy acids undergo decarboxylation. Also, I'm aware of neither the products nor mechanism. All I know is that β-keto acids and α-nitro compounds have ...
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662 views

What should be the correct sequence of reagents to be used in this reaction?

The correct sequence of reagents for the following conversion will be (1) $\ce{CH3MgBr, H+/CH3OH, [Ag(NH3)2]+OH-}$ (2) $\ce{CH3MgBr, [Ag(NH3)2]+OH-, H+/CH3OH}$ (3) $\ce{[Ag(NH3)2]+...
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339 views

Ketal formation of ethyl acetoacetate

Why does the ketone carbonyl group react in preference to the ester carbonyl? Is it something to do with the resonance occurring into the ester carbonyl from the oxygen? but how does this make the ...
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0answers
409 views

How to explain the different regioselectivity of ketones/imines reacting with LDA?

When 1 equivalent of LDA is reacted with, for example, 2-pentanone, you get the thermodynamic (more substituted) product. But when you react butan-2-imine with 1.0 LDA, you receive the kinetic (less ...
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263 views

Primary amine versus phosphoramidate reactivity with succinate esters

I have posted two reactions below. The top reaction is well known and occurs readily and near quantitatively (e.g. in protein modification), while the bottom reaction to my knowledge does not exist in ...
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14 views

Stereoisomers of metaldehydye and paraldehyde

(1) In case of paraldehyde I see 3 similar chiral carbons. So I divided it into 2 subcases -two methyls above the plane and one below the plane -all three above the plane so, that makes it 2. When I ...
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17 views

Does -M Effect increases rate of hydration of aldehyde and ketone?

I saw somewhere written, the rate of hydration of carbonyl compounds depends on: -I group Steric hindrance Intramolecular H bonding Can -M effect also increases rate of hydration?
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Reaction of ketones with cyclic diols

Question In this reaction I am able to figure all reaction except first. What confuses me is the fact than in solution, the cyclic diol reacts only with the aldehydic group. But It can also react ...