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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39 views

Why don't dicarboxylic acids show hydrogen bonding in spite of the fact that carboxylic acids exist usually as dimers in polar aprotic solvent?

I have seen several examples: The fact that maleic acid is more soluble in water than fumaric acid in spite of the fact that it must be able to show intramolecular hydrogen bonding. trans-...
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1answer
612 views

Alcohol or Carbonyl - Which is more reactive towards PCl5?

We're aware that ketones and alcohols both react with phosphorus pentachloride, to produce geminal dichlorides and alkyl chlorides respectively. What happens in the compound shown below, when ...
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3answers
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How to predict the outcome of a crossed Cannizzaro reaction?

My question is, how do we predict the products of a cross-Cannizzaro disproportionation in presence of a concentrated base? i.e, How to judge which of the aldehydes (both don't have any alpha hydrogen)...
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Why is enol content higher in non-polar solvents?

Apparently, for keto-enol tautomerism, the enol content of a given carbonyl compound increases when in a non-polar solvent. What is the reason for this?
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665 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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1answer
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Acidity of aldehydes and ketones and enolate formation

In most academic courses you'd learn that aldehydes are more acidic (lower $\text{p}K_\text{a}$) than ketones due to the lower electron donating effect of the proton compared to the alkyl group of the ...
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52 views

Help with mechanism similar to Robinson Annulation

I need to figure out a mechanism for this reaction. All I know is that it is supposed to have a similar mechanism to Robinson Annulation. This is the best I could come up with, but I've been told it ...
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What about the Methanal having Alkyl? [closed]

In my book, there is a question which mentions formula $$HCHO$$ of Methanal and asks to tell the functional group and alkyl radical. I am confused because its clear that functional group is aldehyde ...
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Reaction Of Grignard's Reagent with Acyl Chloride

My organic chemistry book says that Grignard reagents react with acyl chloride just as hydride reagents. Further in an in-text question now using above theory, my answer is But Answer in Solution ...
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1answer
62 views

Why doesn't propynal give cannizzaro reaction?

Cannizzaro reaction is a disproportionation reaction which is given by aldehydes and ketones having no α-H, forming alcohol (reduction) and carboxylic acid (oxidation) as its products. The compound, ...
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What is reaction between isopropyl alcohol and acetone?

What would be the probable reaction between acetone, $\ce{(CH3)2CO}$, and isopropyl alcohol, $\ce{CH3CHOHCH3}$, at room temperature without any catalyst in different concentrations?
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2answers
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Reduction of hemiaminal by triethylsilane / boron trifluoride

I was trying to understand how the following reaction occurs (taken from a synthesis of homopipecolic acid[1]): I thought that triethylsilane, $\ce{Et3SiH}$, would reduce the ester to an aldehyde. ...
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Mechanism of homologation of aldehyde to alkyne: Ohira–Bestmann reaction

This reaction was part of an organic scheme I was doing, and I was wondering what the mechanism of the reaction would be. I tried first forming a carbene by letting $\ce{N2}$ leave from the ...
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1answer
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Reaction of carboxylic acid with phosphorus trichloride

The reaction of carboxylic acid $\ce{RCOOH}$ with $\ce{PCl5}$/ $\ce{SOCl2}$ / $\ce{PCl3}$ yields an acyl chloride $\ce{RCOCl}$. With $\ce{PCl5}$ and $\ce{SOCl2}$ the reaction is quite simple utilizing ...
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Reagent to reduce aliphatic aldehyde to alcohol while protecting double bond

I have a straight chain, aliphatic aldehyde (liquid) with a double bond in it. I want to reduce the terminal carbonyl group to an alcohol but without touching the C=C double bond. The double bond is ...
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40 views

Fate of compounds after radioactive decay [duplicate]

Let us say there is a $\ce{CO2}$ molecule containing $\ce{^{14}C}$ isotope. $\ce{^{14}C}$ undergoes decay to form $\ce{^{14}N}$. What happens to the molecule?Does it form $\ce{NO2}$? How are the ...
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Why aren't the hydrogen bonds in carboxyllic acids like this?

Why don't carboxylic acids form H-bonds in this formation with the red dots (diagonal) instead of the black dots (horizontal)? I was always taught that H-bonds formed between partially negative and ...
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1answer
110 views

Reaction of 2,3-dichlorobutanoate with a decarboxylating agent followed by hydrochloric acid and then aq. potassium hydroxide

Question $$\ce{CH3-CH(Cl)-CH(Cl)-COO- ->[-CO2]A->[HCl]B->[aq KOH]C}$$ Product C is: a) $\ce{CH3-CH2-CHO}$ b) $\ce{CH3-CH(OH)-CH2-CH2-OH}$ c) $\ce{CH3-CHO}$ d)$\ce{CH3-C(=O)-CH3}$ Answer My ...
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1answer
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Reaction of acyl chlorides with diazomethane and silver(I) oxide

$$\ce{R-COOH ->[SOCl2,CH2N2][Ag2O/CH3OH] X}$$ While solving Carboxylic derivatives recently, I came across this. so following the reagents one by one- $\ce{SOCl2}$ will form acid chloride. $\ce{...
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87 views

Product of the reaction of ethyl acetoacetate with alkaline benzoyl chloride followed by addition of ammonium chloride

What does this β-keto ester give when reacted with $\ce{PhCOCl/NaOH}$ followed by $\ce{NH4Cl(aq)}?$ According to me, the $\ce{PhCOCl}$ should react with $\ce{NaOH}$ forming benzoic acid which should ...
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2k views

How can this ketone show Cannizzaro reaction?

According to answer key, Cannizzaro reaction of 3-hydroxy-2,2-dimethyl-1-phenylpropan-1-one (a ketone) takes place but how is that possible when we know only aldehydes show Cannizzaro reaction?
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Equilibrium between hydroxides and ketones/aldehydes

In the reaction between hydroxides and ketones/aldehydes, an equilibrium will be established between the tetrahedral intermediate and the reactants. For aldehydes, significant amounts of the ...
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1answer
785 views

What is the most acidic proton of 2-methylcyclopent-2-en-1-one?

In an acid-base reaction of $\ce{HO-}$ with 2-methylcyclopent-2-en-1-one, which is the most acidic proton? I had assumed it was one of them coming off C-5 according to IUPAC numbering (the sp3 carbon ...
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3answers
1k views

Does acrolein give Fehling's test?

Aromatic aldehydes do not give Fehling's test, which makes me believe that for the same reason acrolein should not. It has a double bond conjugated with the carbon oxygen double bond as in ...
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Reactivity comparison between benzaldehyde and acetaldehyde [duplicate]

One of my teacher says that $\ce{Ph-CHO}$ is more reactive than $\ce{CH3-CHO}$ in performing nucleophillic addition reaction because $\ce{—Ph}$ is planar and thus offers less steric hindrance as ...
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1answer
391 views

Unusual hydrolysis of methyl 2,4,6‐trimethylbenzoate

Problem 223 from Conceptual Problems in Organic Chemsitry by Singh [1, p. 367]: The given answer is b and I don't get why. Usual ester hydrolysis would've given a. I somehow managed to know that the ...
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1answer
111 views

Nitro-substitution [closed]

Here I expected (b) to happen via nucleophilic substitution, but contrary to that (a) is the one occuring. What exactly is happening here?
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1answer
66 views

Tollen's Test with Salicylaldehyde

I have read that Tollens' test is given by aldehydes. The aldehyde is oxidised to a carboxylate ion and silver is deposited. My teacher had given me notes which pointed that salicylaldehyde does not ...
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1answer
90 views

Beckmann rearrangement v/s dehydration of Oximes

In the above question, A is an oxime, which is then reacted with phosphorus pentoxide. Now, phosphorus pentoxide is both a dehydrating reagent and a reagent used for Beckmenn rearrangement, but which ...
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Cleavage of C-C bond in 1,2-diketo compounds with periodic acid

Today we learned the Malaprade reaction in class. My teacher told me that a similar reaction can take place when the substrate is a 1,2-diketo or 1-keto-2-hydroxy or even 1-hydroxy-2-amino(in presence ...
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1answer
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Stereoisomers of metaldehyde 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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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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Comparison between hot conc. KMnO4 and cold KMnO4

Recently while solving carbonyl compounds I came across this. What all can cold KMnO4 do? Can it oxidize aldehydes too, along with oxidizing alkene to vicinal diols? (I need a thorough comparison in ...
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1answer
100 views

Priority order of attack of grignard reagents on functional groups

Recently I was solving carbonyl compounds and I came across this. Is there some priority order, or logic behind why alcohol reacts first with Grignard reagent and then ketone. Whereas ester could've ...
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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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1answer
29 views

Forming ester from amide using protonated alcohol as catalyst

In my level of understanding, if I want to make an amide from an ester, I should add: $\ce{H3O+}$ for hydrolysis to make carboxylic acid $\ce{SOCl2}$ to form acid chloride $\ce{ROH}$, pyridine to ...
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1answer
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How can benzaldehyde have a pKa of 14.9?

There are numerous websites out there which claim that the pKa of benzaldehyde – C6H5CHO – is 14.90. (Just do a Google search for benzaldehyde pka to see what I ...
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1answer
408 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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0answers
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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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1answer
116 views

Does acetoacetic ester give haloform test?

According to my class notes, acetoacetic ester doesn't give haloform test, but I feel that it should. I know that the methyl group on acetoacetic ester is not responsible for the haloform test. First, ...
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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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2answers
6k views

Mechanism for acylation of benzene with succinic anhydride [duplicate]

I've just started with EAS. I wanted to write down a mechanism for acylation of a cyclic anhydride (for some reason the formation of the carbocation is not given in my textbook). So I wish to know ...
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1answer
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What is the effect of conjugation of a carbonyl group in IR spectroscopy?

Doing an exchange term so I've missed some classes that the others have attended, and unfortunately we're getting contradictionary explanations, so I thought I'd try and ask you. Would be extremely ...
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Enamine Formation in a Diketone

I am trying to form an enamine, and I was trying to figure out if the following reaction is possible: Would this reaction terminate after the formation of the shown product, or will the other ...
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1answer
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Mesomeric effect in crotonaldehyde [closed]

I tried making structures using lone pair of oxygen but I am unable to achieve a structure which doesn't violate the octet rule.
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2answers
1k 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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53 views

In which condition CO uses the oxygen end for bonding?

Generally Metal Carbonyl complex are formed from Carbon end. Is it possible under some specific condition that the Oxygen end is used? (PS -I know about the structures of M-CO bonding)
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Reduction of carbonyl compound by LAH (in anhydrous ether) followed by reaction by acidic water

What will be the final product upon reaction of $\ce{CH2=CH-CH2-C6H4-CH=CH-CHO}$ with $\ce{LiAlH4}$ (in dry ether) followed by acidic water? LAH will reduce the carbonyl group to alcoholic group and ...
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1answer
22k views

How does sodium in ethanol reduce carbonyl compounds?

According to my teacher, Na in ethanol reduces carbonyl compounds (e.g. aldehydes and ketones) to alcohols. However, I can't see where the hydrogen needed for reduction comes from. How does the ...
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2answers
732 views

I am confused about the stability of carbanion III and IV in the image

I am confused about the stability of carbanion III and IV in the image, I think III is more unstable because of electron donating effect (+R) of $\ce{-OCH3}$ group but my book says III is more stable ...

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