A conjugated ring of unsaturated bonds, lone pairs, or empty orbitals which exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. This tag should also be applied to antiaromatic compounds. This tag should not be applied to general questions about ...

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How is spiro[4.4]nonatetraene antiaromatic

How is spiro[4.4]nonatetraene antiaromatic? I know that spiro compounds exhibit homoaromaticity, but how do they exhibit antiaromaticity?
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41 views

Why doesn't benzene undergo electrophilic addition?

A clear explanation would be helpful. Thank you.
2
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1answer
34 views

Why is cyclooctatetraene non planar but the cyclooctatetraenide anion planar?

I was reading some organometallics and I came upon the preparation of uranocene. It has two cylcooctatetraenide anions as ligands with a Uranium atom inbetween. The author has mentioned that the ...
4
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0answers
32 views

Is the para-position of anisoles more reactive than ortho in electrophilic substitutions?

In my group’s seminar last Friday, we discussed the total synthesis of 6-demethyl-6-deoxytetracycline 1 by Woodward et al.[1] One intermediate of their synthesis is meta-substituted anisole 2 that ...
4
votes
1answer
35 views

Activity of different positions in phenol with respect to electrophilic aromatic substitution

Which of the statements below is correct? a) The ortho and para positions are more active than the meta position. Or b) The ortho and para positions are activated while the meta position is ...
3
votes
1answer
41 views

Why do we need to add FeBr3 for bromination of anisole, but not for bromination of phenol?

I understand that we need to add $\ce{FeBr3}$ while brominating benzene in order to polarize the bromine molecule. However, we do not need to add such a Lewis Acid in the case of phenol, because it is ...
5
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0answers
82 views

Is the following molecule aromatic?

Is the following molecule aromatic? It does seem like it will be aromatic because it is similar to furan. I am confused because of the positive charge on the $\ce{N}$.
10
votes
1answer
122 views

Phenyl group in proton NMR

Suppose you have this spectrum and the molecular formula of $\ce{C10H12O}$ The structure is My problem is with the peak at ~7 which is an H-Benzene signal, with quartet splitting and a relative ...
15
votes
1answer
368 views

Why isn't the Silicon analogue of Benzene flat?

Why isn't the Silicone analogue of Benzene flat? As far as I understand, Silicon and Carbon make similar structures and it doesn't make sense that it's benzene analogue should be substantially ...
4
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1answer
44 views

hydrogen environments of benzenephenone

The hydrogen in $\ce{C4}$, $\ce{C6}$, $\ce{C10}$ and $\ce{C8}$ belong to same hydrogen environment. The hydrogen in $\ce{C3}$, $\ce{C1}$, $\ce{C11}$ and $\ce{C13}$ belong to the another hydrogen ...
7
votes
2answers
93 views

Is the conjugate base of trinitromethane aromatic (What is Y-aromaticity)?

The wikipedia article on trinitromethane claims that: There is some evidence that the anion (which obeys the 4n+2 Hückel rule) is aromatic. Unfortunately the citation is behind a paywall so I ...
7
votes
1answer
143 views

Thermodynamic vs Kinetic Sulphonation of Naphthalene

The left hand isomer is clearly the kinetically favoured product and the right hand isomer is the thermodynamically favoured product. However, I have no idea why. Can you explain?
1
vote
1answer
24 views

Can 4-pyridones be synthesised analogously to 2-pyridones?

I understand that 2-pyridone derivatives can be synthesized by oxidizing an N-methyl pyridinium salt with $\ce{[Fe(CN)6]^3-}$ under basic conditions. Can a similar method be used to produce ...
13
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1answer
85 views

Interlocked Cyclic Compounds

Being new to chemistry, there may ought to be some properties I couldn't understand fully. One of them being cyclic compounds. One particular question about this is, whether these cyclic compounds, ...
6
votes
2answers
71 views

Is the resonance depiction of benzene typically portrayed incorrectly?

I can understand that the carbon atoms in benzene have delocalized p electrons that are shared amongst all 6 of the carbons in a cloud on either side of the ring. I also understand why this could be ...
4
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0answers
42 views

Different elution profiles of carvacrol and thymol

I have identified carvacrol and thymol via thin-layer-chromatography and via gas chromatography On a normal silica plate the thymol has a higher Rf-value then carvacrol. The explanation for this would ...
6
votes
2answers
181 views

Is nitrogen of aniline sp² or sp³ hybridized? [duplicate]

I found a thread which discussed this which totally confused me. (refer to the part of the link which talks about $\ce{sp^2/sp^3}$) The question "How to rationalise the resonance structures and ...
13
votes
1answer
153 views

What is the justification for Hückel's Rule?

I know that experimentally, the rule has been verified but I am having trouble understanding why it works. I see no reason why equivalent cyclic structures can undergo resonance and be just as stable. ...
3
votes
1answer
75 views

Basicity Alteration Due To Ortho Effect In Methoxy Aniline System

I wanted to ask something more in reference to this question Ortho-effect in substituted aromatic acids and bases Suppose instead of toluidine, 2-methoxy aniline and 3-methoxy aniline are ...
3
votes
1answer
39 views

Why are esters meta directors? Can't the carbonyl donate electrons into the ring?

I'm having trouble understanding why an ester is a meta directing/deactivating group. I'm not talking about an ester with its oxygen bound to the ring, like an acylated phenol. I mean the R group is ...
5
votes
1answer
95 views

Acidity of unsaturated five membered ring relative to seven membered analogue

Which of the following is more acidic? The most acidic proton is positioned on the carbon that is at the top of the above drawings (the methylene hydrogens) on each of the two species as ...
2
votes
1answer
62 views

Why is acetylsalicylic acid still more acid than benzoic acid?

In this question, it is explained why salicylic acid is a stronger acid than benzoic acid. So, why acetylsalicylic acid (aspirin), whose conjugate base cannot hydrogen bond since there is no hydrogen, ...
5
votes
1answer
184 views

Nitration of pyrrole

Would 2,5-dinitropyrrole be a product of nitration of pyrrole with $\ce{H2SO4/HNO3}$ ? It seems from this paper that it is not formed using acetic anhydride/nitric acid. Is this just because of the ...
5
votes
1answer
227 views

Determining aromaticity of compounds

Which of the following planar structures would be aromatic? Could someone help me determining the aromaticity of the compounds? My Attempt: (i) Not an aromatic compound since it only has 4 ...
8
votes
1answer
72 views

Naproxene syntheses: electrophilic aromatic substitution on activated naphthalene

I am studying Syntex's naproxene syntheses and I came across a couple of electrophilic substitutions whose mechanism I can't understand. The first one is a Friedel-Crafts acylation: the products are ...
3
votes
1answer
92 views

Are these aromatic?

I believe these are all aromatic, as they all follow Huckel's rule of 4n+2 pi electrons. Is the last molecule also aromatic?
2
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0answers
24 views

What mass of fragrances does a cubic meter of air contain on average? [closed]

What mass of fragrance are airborne in scented environments for example in a perfume deparment? What is the minimum g/m3 of fragrance that a human can detect, and how much is present when it ...
2
votes
1answer
77 views

How can I deduce the structure of my compound from this NMR spectra?

I have no idea how to determine the substituents on the aromatic ring from this NMR spectra. There is (or ‘might be’) a triplet on my NMR around $7.59 - 7.65\,\mathrm{ppm}$ which has 4 hydrogens ...
2
votes
1answer
153 views

NMR: Magnetic and chemical equivalence in benzene

According to my textbook, all the protons in $\ce{^{12}C_6{}^{1}H_6}$ are magnetically equivalent, but those in $\ce{^{13}C_6{}^{1}H_6}$ are not. I understand that for two nuclei to be magnetically ...
3
votes
1answer
167 views

Resonance of Aromatic compounds

I have a confusion... Do compounds like tropolone, furan and thiophene which are aromatic show resonance? If yes then what are the resonating structures ? Also do all aromatic compounds show ...
0
votes
1answer
55 views

What is the reasoning behind the resonating structure of halo-benzene? [closed]

Can anyone explain the resonating structure of halo-benzene? How does the transfer of an electron from the halogen atom to the α-carbon and from there to ß-carbon and so on take place?
1
vote
1answer
141 views

Why aryl halides are very less reactive towards nucleophilic substitution reactions? [duplicate]

I've often herd that aryl halides are very less reactive towards nucleophilic substitution reactions. One of the reasons for this I found was that there is resonance effect in the compound, but how is ...
3
votes
3answers
93 views

When does nitrogen contribute its electrons to aromaticity?

I've been told that this molecule is aromatic. As it has four obvious pi electrons (in the double bonds), I assumed that it was anti-aromatic as opposed to aromatic. I've been operating under the ...
5
votes
1answer
213 views

Electrophilic substitution of pyrrole (regioselectivity)

Why when pyrrole participates in an EAS, the alpha position is so much preferred over the beta position?
2
votes
1answer
63 views

Why isn't this a compound?

I don't know what to call it I'll just provide a link. From what I can tell it is impossible, but why? http://www.chemicalize.org/structure/#!mol=structureId%3A1609384473364&source=calculate
6
votes
2answers
408 views

Why is a hydroxyl group more activating than a methoxy group in electrophilic aromatic substitution?

Why is phenol more reactive towards electrophilic substitution than methoxybenzene? Isn't the lone pair on the methoxy group oxygen more available for participating in resonance into the ring than the ...
3
votes
1answer
89 views

Why do the two methylene protons in ethylbenzene have a chemical shift at 2-2.9?

The data sheet does not have any chemical shifts in this range for compounds containing only carbon and hydrogen
6
votes
1answer
39 views

Aromatic ring substitution: how are MNT and DNT further nitrated if nitro groups deactivate benzene rings?

This is probably a common question because it involves TNT precursors, but if an $\ce{NO2}$ group deactivates benzene rings toward electrophilic aromatic substitution reactions, then how can toluene ...
2
votes
1answer
52 views

Friedel-Crafts synthesis - How is HCl produced?

In the mechanism for the acetylation of bromobenzene, how is $\ce{HCl}$ gas produced? The reactants are acetic anhydride, bromobenzene, $\ce{AlCl3}$ and dichloromethane. Initially, ...
4
votes
1answer
151 views

Acetylation reaction

In the Friedel - Crafts acetylation of bromobenzene, how is it possible to obtain a black-coloured product? When the acetic anhydride was slowly added to the reactants - $\ce{AlCl3}$, DCM, ...
2
votes
2answers
227 views

Resonance structure of cyclobutadiene?

I studied cyclobutadiene as an anti-aromatic compound. But I am unable to draw the resonance structures for cyclobutadiene. Can anyone help me? What is the driving force for the resonance to start? ...
4
votes
2answers
195 views

What is the resonance structure of nitro-aminobenzene with a broken aromaticity?

According to my course of organic chemistry, nitro-aminobenzene has to break his aromaticity to delocalize the electrons of the amino-group in the nitro-group. I don't really see this, when I draw the ...
0
votes
1answer
67 views

Electrophilic aromatic substitution with fluorine

Why don't we usually use diatomic fluorine in electrophilic aromatic substitution? Is it because fluorine is a potent oxidizer and will react with the carbons? What might happen if we reacted ...
3
votes
2answers
397 views

why is benzoic acid stronger acid than 3-aminobenzoic acid?

why is m-aminobenzoic acid weaker acid than benzoic acid? obviously at m-position only -I effect will be shown but how doeas that make it a weaker acid than benzoic acid??
4
votes
1answer
931 views

Is the Nitrogen in pyridine electron withdrawing and what effect does this have on electrophilic substitution?

If I were to attempt to nitrate Pyridine (essentially benzene but with one carbon replaced with Nitrogen) would I get substitution at the Ortho-, Meta- or para position? Also why is this? I can only ...
2
votes
2answers
123 views

Extended conjugation in cyclic ketone

This is a continuation of Aromaticity of cyclic ketone So, I'm looking at the molecule that does have the carbonyl double-bond. Is this resonance structure considered aromatic? Would the electrons ...
5
votes
3answers
313 views

How are Phenols made?

What are the equation and condition for the synthesis of Phenols? Would it work if we added NaOH to Benzene and then reflux?
6
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2answers
246 views

Role of Alcohols(EtOH,MeOH) in nitro reduction used for Metal(Sn,Fe)

I'm trying to reduce an aryl nitro group. I understand that these reactions are radical reactions by the metal, but I don't understand why alcohols are used as the solvent. Are they used as a ...
5
votes
1answer
749 views

Structure of carbon fiber

What is the structure of carbon fiber? Wikipedia doesn't give much insight. The atomic structure of carbon fiber is similar to that of graphite, consisting of sheets of carbon atoms (graphene ...
2
votes
1answer
348 views

Difference between any arene and an aromatic compound?

I can't seem to find what the difference between these two is. In my text book, it says that 'arenes are aromatic hydrocarbons containing one or more benzene rings' which to me suggests that arenes ...