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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3
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1answer
166 views

Equation for the equilibrium constant for the hydration of carbonyls using UV spectroscopy

I was looking through the literature when I found a paper by Greenzaid et al. [1] which states that the equilibrium constant $K_\mathrm{hyd}$ is: $$K_\mathrm{hyd} = [\text{hydrate}]/[\text{carbonyl}...
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2answers
412 views

Mechanism with hypohalite in haloform reaction

The haloform reaction is usually done in a solution of NaOH and $\ce{I2}$ (or indeed, any halogen). Now the first part of the reaction mechanism in the wikipedia page and in the most organic books ...
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1answer
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Oxidation of ascorbic acid (Vitamin C)

What would you suggest me to use for oxidation of vitamin C to dehydroascorbic acid instead of bromine water?
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Why does formic acid give positive Fehling's test?

$$\ce{HCOOH ->[\text{Fehling's solution}] CO2 + H2O}$$ The points discussed in a previous question do not account for the fact that formic acid also gives positive Fehling's test since it is not ...
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1answer
3k views

Cram's rule for nucleophilic addition to carbonyl groups

I recently heard about Cram's rule for predicting the stereoselectivity in nucleophilic additions to carbonyl groups. Can anybody explain what this is and whether it is an accurate rule?
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1answer
59 views

Which of the following isomers of 2,3‐dihydroxy‐4‐methoxy‐4‐oxobutanoic acid are identical?

Which of the following are identical? A and B are identical A and B are diastereomers A and C are enantiomers A and B are enantiomers What I know is that when we rotate a ...
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2answers
120 views

Why acidity of p-methoxybenzoic acid is more acidic than p-hydroxybenzoic acid?

I know +M effect of $\ce{OCH3}$ is more than $\ce{OH}$, but in my book (ALLEN General organic chemistry), it is given that $\mathrm{p}K_\mathrm{a}$ of para-substituted benzoic acid containing $\ce{...
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45 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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60 views

What should be IUPAC name of given compound (see image)? [closed]

I think the name should be 1-carbamoylpentane-3-sulphonic acid, but the answer sheet mentions it as 2-carbamoylpentane-3-sulphonic acid: Can anyone please explain why the chain starting with methyl ...
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2answers
306 views

What's the reason for the instability of ethylene dione?

Ethylene dione, with a chemical formula $\ce{C2O2}$ and an IUPAC name of ethene-1,2-dione, is an oxocarbon. The Wikipedia page says: The existence of $\ce{OCCO}$ was first suggested in 1913. ...
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1answer
220 views

Inductive vs conjugation effects in ester hydrolysis

I just came across the following problem about alkaline ester hydrolysis: Since all of the substituents are in the para position, I immediately thought about the ability of those substituents to ...
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2answers
6k views

In the condensation reaction of an aldehyde with a hydroxyl amine, why is an oxime formed and not an amide?

Condensation reactions are those that involve removal of a water molecule. When you analyze the reaction between an aldehyde and hydroxyl amine, I don't understand why it's not possible for the acidic ...
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1answer
116 views

Energy cost of C−N rotation in hydroxamate group

I am looking for a literature reference on the energetic cost of C−N rotation in hydroxamate group such in LC5 in water. I have been googling for a while.
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LiOH hydrolysis of methyl 2,2-dimethoxyacetate not giving product?

I am forming 2,2-dimethoxyacetic acid from its methyl ester, and below is the experimental protocol I am following (from Tetrahedron 2016, 72 (3), 420–430): 2,2-Dimethoxy Acetic Acid Formation ...
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613 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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2answers
4k views

Dehydration of amide with PCl5

Can $\ce{PCl5}$, phosphorus pentachloride, react with an amide? I saw a reaction where the corresponding cyanide was formed in this process. What other reagents could do the same?
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Esterification of a carboxylic acid and the production of water

In an esterification reaction between a carboxylic acid and an alcohol, a carboxylate ester and water is produced. I found the following diagram online, and my textbook has a similar one as well ...
7
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3answers
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Why amino acids (Zwitterion) become either negative or positive at low and high pH solutions?

The amino acids are Zwitterions. In neutral pH, an Amino acid's amino group has a postive charge and Carboxyl group has negative charge. They cancel each others charge thanks to the $Hydrogen$ that's ...
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2answers
150 views

Orbital size of Carbon and Oxygen in Methanal

I was given an introductory question into Carbonyl chemistry today and I wanted to ask a question about Methanal. The following picture was shown below of Methanal: and I noted that the orbital ...
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2answers
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Will cinnamaldehyde undergo self-aldol condensation?

Will cinnamaldehyde undergo self-aldol condensation? My book says it won't, but since it has an α-hydrogen, I'm confused.
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1answer
266 views

On the mechanism of the nitrogen-removal step of the Wharton olefin synthesis

In today’s reaction seminar, the Wharton transposition made an appearance. In our practice case it started from the epoxide as in scheme 1 below as on Wikipedia; Kürti/Czakó (page 482) begin from the ...
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1answer
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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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70 views

Confusion with IUPAC naming of Morphine

I'm having trouble understand what sections of the molecule morphine relate to what sections of its corresponding IUPAC name of (4R,4aR,7S,7aR,12bS)-3-methyl-2,4,4a,7,7a,13-hexahydro-1H-4,12-...
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Do alpha hydroxy ketones give iodoform test

So, we know that alpha hydroxy ketones give tollens test as the tautomerise into their enol form and the then have an equilibrium between the 2 keto forms. So going ahead with the same logic. Do ...
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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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1answer
60 views

Fluorination of Carbonyl Compounds using Molybdenum Hexafluoride

What is the mechanism of halogenation of carbonyl compounds using molybdenum hexafluoride? How does it work? Here's a reaction I came across: Can we use it for all carbonyl compounds? Are there ...
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1answer
287 views

Protonating/basic site and Brønsted basicity orders of beta, gamma, and delta lactams

Consider the three cyclic amides: $\beta$-lactam $\gamma$-lactam $\delta$-lactam My question What is the basic site (site of protonation) for these three lactams? And what should be their Brønsted ...
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3answers
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Which compound reacts faster in the Cannizzaro Reaction?

Which reacts faster in the Cannizzaro Reaction? a) $\ce{OHC-C6H4-NO2}$ b) $\ce{OHC-C6H4-OCH3}$ Obviously, a better hydride releasing group will react faster. Therefore my answer was b, as $\ce{-...
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2answers
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Can an amide nitrogen be a hydrogen bond acceptor?

Can $\ce{N}$ (i.e. main chain $\ce{NH}$s of recognised residues in a peptide or protein) be a hydrogen bond acceptor? It is a well known fact that the main chain $\ce{NH}$s can be a hydrogen bond ...
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0answers
125 views

Mechanism of decarboxylation of cyclohexane-1,2-dicarboxylic acid

According to FIITJEE's Sankalp Test-II answer key, it was given that the following compound decarboxylates on heating: Then, I read Why are beta-ketoacids better at decarboxylation than gamma or ...
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27 views

Diketone intramolecular reaction question

I realize that one of the methyl groups on either carbonyl compound will become deprotonated and then it will attack the other carbonyl to form a pentane ring. However, with the methyl group in the ...
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0answers
25 views

Is the 1,4-adduct of carbonyl compounds ever a major product over the 1,2-adduct?

If, say, propenal undergoes nucleophilic addition of hydrazine, will the 1,2- adduct or the 1,4-adduct be preferred? Why? There is an obvious reasonace structure with an electrophilic beta carbon so ...
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1answer
128 views

Is there a systematic naming system to name carbonyl derivatives?

I had asked a question earlier about how the “$\ce{-COOCl}$” functional group would be named. I had received a satisfactory answer that helped me completely understand how that compound was named. ...
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Sources of carbon monoxide in dwellings

I am doing some research on indoor environmental quality and come across a number of spikes in CO in a dwelling. This is a dwelling in central London with no gas-fired equipment: electric cooker and ...
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0answers
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Why do carbonyl groups lower antibonding orbital energies of conjugated systems?

In the chapter on conjugation in Organic Chemistry by Clayden, Greeves, Warren and Wothers, there's a brief discussion of pigments with conjugated systems that includes the following paragraph (first ...
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0answers
255 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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Rearrangements of α-aminoketones in Clemmensen reduction

What is the possible mechanism for this reaction? Activated zinc in presence of concentrated hydrochloric acid is used for Clemmensen reduction, that is conversion of ketone group to methylene group. ...
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0answers
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Heating of cyclic dicarboxylic acid [closed]

How do we predict the products formed when we heat cyclic dicarboxylic acids? I know that in case of aliphatic dicarboxylic acids we apply Blanc's rule and predict the product formed based on the ...
5
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1answer
175 views

Intramolecular lactonisation in an unsaturated carboxylic acid

I am having some trouble figuring out how this reaction proceeds: Attempt 1: The most obvious thing to do is deprotonate the acid group. I tried using the carboxylate group to attack the alkene, ...
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1answer
62 views

Are all fatty acids monocarboxylic acids?

The answer to this question might solve a multiple choice in my previous chemistry exam, which caused an argument with my teacher. We know that fatty acids form fats and oil due to their carboxylic ...
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2answers
411 views

How do α,β-unsaturated acids undergo decarboxylation?

I know the concerted mechanism for β-keto acids, but neither could I figure out, nor was I able to find out the mechanism for α,β-unsaturated acids. Any help is appreciated.
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60 views

Why are carbonyl groups so important [closed]

The most important are π orbitals as they are lower in energy than σ orbitals and the carbonyl group (C=O) is the most important of these—indeed it is the most important functional group of all. ~...
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Difference between base-promoted and base-catalysed

Why is halogenation of ketones in base described as being "base-promoted" and not "base-catalysed"? If the reaction is not "catalyzed" then how is the base used up?
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Why do carbonyl compounds undergo nucleophilic and not electrophilic addition?

Why aldehydes and ketones undergo nucleophilic addition reactions and not electrophilic addition? Alkenes show electrophilic addition because of pi bond, which is also present in aldehydes and ...
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What causes the blackening of light bulbs

in 1878, Thomas Edison (or rather William Joseph Hammer) added an anode in a light bulb in order to catch the flux of electrons coming out from the carbon filament and reduce the phenomenon of ...
3
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1answer
93 views

Grignard alkene on a carbonyl

I was given the following mechanism to prove today post-lecture: and my attempt is given below. Now, when the negative charge on the alkene attacks the carbonyl, the electrons are pushed onto the ...
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2answers
717 views

Reaction of coumarin with phenylmagnesium bromide

I came across this problem.. I thought that the Grignard reagent, PhMgBr, would cleave the lactone and then subsequently add to the ketone formed, giving an allylic tertiary alcohol after aqueous ...
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83 views

Acidity order of carboxylic compounds [duplicate]

Arrange the following acids in decreasing order of acidity: (a) X > Z > Y (b) X > Y > Z (c) Z > X > Y (d) Z > Y > X I arrived at option (c) according to -I effect, but the answer ...