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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16
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1answer
54k views

What is the mechanism for oxidation of ketones by the Popoff's rule?

Ketones are relatively much harder to oxidise, but they do undergo oxidation reactions at extreme temperatures. Our teacher also told us about Popoff's rule which states that, on oxidation of ...
3
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2answers
62 views

Acidic strength comparison of squaric acid and rhodizonic acid

These two are dibasic acids with the following structures (squaric acid and rhodizonic acid in order). Empirical evidence proves that squaric acid is more acidic than rhodizonic acid. It is a ...
2
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0answers
46 views

When do the Wolff-Kishner Reduction and Clemmensen Reduction not take place for carbonyl compounds?

I came across some examples of organic compounds with acidic groups that didn't undergo the Clemmensen reduction. So, I was wondering which types of compounds the two reagents cannot reduce. Also, why?...
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0answers
41 views

During of Formation of aldol why Enolate ion react from carbon double bond end even though carbonyl group is a hard electrophile

When we are reacting 2 moles of an aldehyde /ketone ( with alpha H ) with OH- as base to form aldol first step is formation of Enolate ion by reaction of OH- with acidic alpha H, second step is ...
1
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0answers
87 views

IUPAC name for compound with various carbonyl groups

I found this question on a resource video for IUPAC Nomenclature for a competitive exam. It would be great if someone provided the approved IUPAC approved name for this compound. Source of the ...
3
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2answers
76 views

How can you qualitatively tell when the hydrolysis of aspirin is over?

I'm doing an experiment on the effect of temperature on the time taken to produce acetic acid and salicylic acid. Are there any qualitative observations I can make about when the reaction has finished?...
0
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1answer
52 views

Mesylation of cyanohydrins [closed]

Is it possible to add methane sulfonyl chloride to benzaldehyde cyanohydrin, or add toluene sulfonyl chloride to form the tosylate group on the alcohol and then perfom a grignard reaction on the ...
1
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0answers
683 views

Why is the hydrogen atom adjacent to the carbonyl carbon of aldehyde not acidic?

In $\ce{H^a-CH_2-CO-H^b}$, why is $\ce{H^a}$ more acidic than $\ce{H^b}$ ? From what I know, $\alpha$ hydrogen ($\ce{H^a}$) is highly acidic and is easily abstracted in presence of base $\ce{OH^-}$. ...
3
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1answer
168 views

Do all α-hydroxy ketones give Tollens’ test?

It is well known that terminal α-hydroxy ketones give Tollens’ test, via tautomerisation. Also, α-hydroxy ketones flanked by aromatic groups give Tollens’ test, such as benzoin. But do all α-hydroxy ...
1
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1answer
163 views

Why doesn't H₄CO₄ exist as a stable compound?

Why doesn't $\ce{H4CO4}$ exist as a relatively stable compound? Its heavier homologue $\ce{H4SiO4}$ seems to exist although it is unstable to some extent but new methods have been able to stabilise ...
15
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2answers
22k views

Does Br2/H2O oxidize all aldehydes including carbohydrates?

In many books, it is mentioned that aldehydes are easily oxidized even by mild oxidizing agents. However, I have never seen bromine water explicitly mentioned. But in the carbohydrates chapter, it is ...
12
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1answer
6k views

Why do alpha-hydroxy ketones respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests?

I learnt from a certain textbook that aldehydes and formic acid respond positively to Tollens', Fehling's, Benedict's, Schiff's and HgCl2 tests. However, in another textbook I read that even alpha-...
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0answers
72 views

Etard's reaction

My textbook says the following on Etard's reaction: Now, if the alkyl group attached to benzene is an unsymmetrical or branched alkyl group, such as this: What will be the reaction product(s)? Which ...
3
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1answer
203 views

Mechanism of decarboxylation of alpha-keto carboxylic acid

What is the probable mechanism for the following reaction? $\alpha$-Keto acids on heating with conc.$\ce{H2SO4}$ undergo decarboxylation to give monocarboxylic acids: Also, which of the two carbons (...
5
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1answer
260 views

Possible dehydration after nucleophilic addition

Here is the question: My reasoning was the following: The ethoxide ion first abstracts a proton from the $\mathrm{sp^3}$ carbon of the cycloalkene. This carbon then attacks the electrophilic carbonyl ...
1
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0answers
48 views

A problem on Intramolecular Cannizzaro's Reaction

My textbook has the following reaction given as a special case of Intramolecular Cannizzaro reaction: As far as I understand, here one Phenyl group migrates (instead of hydride ion) from the carbonyl ...
2
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0answers
46 views

Why aren't both alpha-carbons halogenated when acetone reacts with chlorine under UV?

My book shows the following reaction: Why is only one alpha carbon halogenated? I googled, but couldn’t find anything on it.
5
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2answers
292 views

Can Mg/ether reduce carbonyl groups?

One of the ways of preparing Grignard reagent is: $\ce{R-X ->[Mg/ether] R-MgX}$ However let's assume that a carbonyl group is present along with a halide in the substrate. Will $\ce{Mg/ether}$ ...
9
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1answer
422 views

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 ...
1
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1answer
94 views

Can a Lindlar catalyst reduce aldehydes, nitriles, and carbonitriles?

The major product obtained in the following reaction is: Question source: JEE Main 2019 The molecule shown as product is the official answer given by JEE from the given options. I have written the ...
10
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2answers
6k views

Why is in the reaction of cyclic unsaturated aldehydes with hydrazine and hydrogen peroxide the aldehyde preserved?

Question What is the product of this reaction? The answer given: At first, I thought this was a typical Wolff-Kishner reduction, but then I saw the reagents didn't match up (no $\ce{OH-}$...
5
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1answer
185 views

Formation of tetrazoles from ketones in Schmidt reaction

Normally in Schmidt reaction of ketones, amides are formed however for some reason here further reaction takes place and a tetrazole is formed. Here is my try for this reaction mechanism (if my ...
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1answer
48 views

Does rearrangement occur in schmidt reaction? [closed]

I recently read about schmidt reaction in which a carboxylic acid is converted to an amine. While forming this, acyl carbocation $(\ce{RCO+})$ is formed, so does rearrangement takes place or reaction ...
8
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1answer
129 views

Why does LiAlH4 reduce the double bond of cinnamaldehyde, whereas it does not reduce the double bond in crotonaldehyde?

$\ce{LiAlH4}$ is a strong reducing agent capable of breaking the double bonds. It does break the double bonds in cinnamaldehyde. Shouldn't $\ce{LiAlH4}$ be able to break the double bond in ...
3
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0answers
49 views

Does the nucleophilic substitution in an acid chloride always proceed through a tetrahedral intermediate?

I am a beginner in organic chemistry and would like to ask for the mechanism for the nucleophilic substitution of carbonyl groups from acid chloride - especially regarding the tetrahedral intermediate?...
5
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0answers
137 views

Does periodic acid 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 ...
4
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0answers
57 views

2-Iodoxybenzoic acid oxidation reaction

I was thinking about using 2-Iodoxybenzoic acid to selectively oxidize primary alcohols to aldehydes. I've found papers using various solvents like acetone/water mixture1, 2-methyl-2-propanol2, DMSO ...
13
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1answer
52k views

How do you identify reducing / non-reducing sugar by looking at structure?

Identifying reducing / non-reducing sugar been confusing me for a while now , I know that reducing sugar contain aldehyde or ketone group . It's easy to identify them in monosaccharides but this ...
0
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2answers
67 views

Major product formed when 4-Methoxybenzil is reacted with a base

What will be the major product formed in the given reaction: I am not able to apply any of the reactions or mechanisms I know of in this case. The only thing I am able to predict is that the $\ce{OH-}...
2
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2answers
153 views

Decarboxylation of primary amino acids

Since primary amino acids like glycine, alanine can't be decarboxylated under oxidative conditions, what would be the best catalyst for this reaction? I was thinking about copying decarboxylases with $...
1
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1answer
78 views

Double bond or carbanion for nucleophillic attack [closed]

I came across this question: According to me the Hydride ion should take hydrogen from left (unsubstituted carbon) because carbanion will be more stable there and this carbanion will then act as a ...
2
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1answer
727 views

Reduction using hydrazine and glycol in alkaline medium

Question: This question was asked in my exam and I have done it properly until the third step. Unfortunately, although the last step looked like Wolff-Kishner reduction to me, I could not do it. My ...
1
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2answers
134 views

Chirality and number of sterioisomers

I have recently read that the number of sterioisomers in a compound having n chiral centres is $2^n$. (That is, if no meso form is present) The below question asks for the number of sterioisomers in ...
18
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1answer
6k views

Are groups other than carbonyl reduced by Clemmensen reduction?

According to my textbook, Clemmensen reduction reduces only aldehydes and ketones to alkanes. But in this question: $\ce{Zn-Hg/HCl}$ has reduced both the ketonic and nitro group. Correct answer given ...
14
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1answer
5k views

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?
2
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1answer
134 views

Reaction of acyl chloride with excess Grignard reagent

I have a reaction to which I must find the majority organic product. I think I found the correct product but the fact that the reaction takes two moles of propylmagnesiumbromide confuses me a bit. I ...
6
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2answers
373 views

A possible reaction of heating Terephthalic acid

There is no reaction of terephthalic acid heating effect on the internet (at least Wikipedia). I have written the most probable reaction possible as per my knowledge. Please tell if it is spontaneous ...
3
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1answer
72 views

The dependency on electron density in the reactivity order of electrophilic and nucleophilic additions

It is well-known that for electrophilic addition across an alkene, the reactivity increases when intermediate carbocation is more stable (eg. addition of $\ce{HBr}$ or acid-catalyzed addition of $\ce{...
4
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2answers
286 views

What is the major product in the reaction between 4-chloropentanal and lithium aluminium hydride?

What would be the major product between 4-chloropentanal and $\ce{LiAlH4}$? After the reduction of the aldehyde, would the hydroxyl group formed at $\ce{C-1}$ attack $\ce{C-4}$ causing cyclization to ...
11
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1answer
488 views

Does folic acid contain a benzyl or a phenyl group?

I'm studying for my MCAT currently and I stumbled upon this question. It gives the structure of a folic acid molecule and asks what functional groups can be found within the molecule. I understand ...
-2
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1answer
74 views

D and L configuration of monosaccharides

I got this question in the last week's test from Organic Chemistry. I am a bit confused in assigning D and L configuration. Help me understand the topic of D and L configuration and help with this ...
7
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3answers
14k views

Does DIBAL-H reduce carboxylic acids?

Diisobutylaluminium hydride(DIBAL-H) reduces only carboxylic acid, ester or both? The answer given was that it only reduces ester. Is it correct that under any condition carboxylic acids are not ...
1
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0answers
105 views

Does formaldehyde and ethylene glycol give positive Fehling's test?

Fehling's test follows a single electron transfer mechanism, with electron transfer form the substrate to $\ce{Cu^2+}$, which forms $\ce{Cu^1+}$finally giving reddish brown precipitate of $\ce{Cu2O}$. ...
5
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1answer
606 views

Why is para-aminobenzoic acid more acidic than ortho-aminobenzoic acid?

Compare the acidic strength of o-, m-, p-aminobenzoic acids. I got that meta will be the most acidic as it won't be able to show R+ effect of $\ce{NH2}.$ But among the other two, i.e. ortho and para, ...
4
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1answer
78 views

Why does a methyl shift occur during the pinacol-pinacolone rearrangement?

Why does a methyl shift occur during the pinacol-pinacolone rearrangement? I was told that methyl shift is done to stabilise the carbocation but here we are shifting the ...
17
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3answers
69k views

Why are the boiling points of aldehydes less than those of ketones?

Both aldehydes and ketones have a carbonyl group, but since the carbonyl group of ketone is between alkyl groups, wouldn't it be more difficult for it to form hydrogen bonds than aldehydes? Why then, ...
0
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0answers
26 views

Trend in Boiling Points of Aldehydes vs Ketones

Up until 2-pentanone/3-pentanone and pentanal, the boiling points of unbranched ketones are higher than those of unbranched aldeyhdes that have equal number of carbons as explained by "matt_black&...
3
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1answer
10k views

Oxidation of Unsymmetrical Ketones using Selenium Dioxide

I have searched the whole internet but I could only see examples where the authors of the article took $\ce{R1}$ and $\ce{R2}$ as the alkyl groups around the carbon. This is regarding the oxidation of ...
0
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1answer
66 views

ketone and amine condensation

My question is quite easy to solve. The question simply asked to find the final product of the reaction shown below, which I did. But the my question lies in the catalyst. What is the role of the ...
-2
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1answer
44 views

Nucleophilic comparison of epoxides and ketones [closed]

Why does $\ce{H+}$ attack on epoxide and not on the double bonded oxygen?

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