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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Hybridization of nitrogen in a ring [on hold]

Is there a well defined way to discern the hybridization of a nitrogen atom in ring, like pyrrole? How can you know whether the nitrogen's lone pair are in the conjugated system or not?
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27 views

Nitration of p-nitrotoluene [on hold]

Why the p-nitrotoluene on further nitration gives o,p-nitrotoluene not the m,p-nitrotoluene . According to me in m,p-nitrotoluene there is +M NO2
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15 views

Ortho para or meta directing [duplicate]

As we know CH3 is ortho para directing . Then why the following rection gives meta directing .
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2answers
66 views

Is ciprofloxacin acidic or basic?

I would expect an aqueous solution of ciprofloxacin to be basic for the following reasons: The carboxyl group has pKa = 6.09 and the secondary amino group has pKa = 8.74. Because 8.74 is further ...
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678 views

Why is pyrimidine less basic than pyridine?

From Wikipedia's article on pyrimidine: Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile. But why is pyrimidine less basic than ...
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1answer
70 views

Why is the lone pair of pyridine's nitrogen atom not part of the aromatic ring?

In pyrrole, the lone pair of electrons belonging to the nitrogen is part of the aromatic ring. However, in pyridine it is part of an sp2-hybridized orbital. Why can't it be in the p-orbital and take ...
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41 views

Which substituent in the benzene ring activates it most towards electrophilic substitution?

I came across the following question in my textbook: Which of the following gives electrophilic substitution reactions most easily? Phenol Chlorobenzene Benzene Methylbenzene I tried drawing ...
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2answers
82 views

Why can't oxygen in furan be sp-hybridized?

From ChemWiki's article on Huckel's Rule: So far, you have encountered many carbon homocyclic rings, but compounds with elements other than carbon in the ring can also be aromatic, as long as ...
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77 views

How much steric hindrance does a phenyl group offer?

I've come across a question in my revision in which I am asked to compare the steric hindrance provided by a number of substituents. Those relating to phenyl are ranked relatively low, despite it ...
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1answer
60 views

Why are anti aromatic compounds unstable?

Just like aromatic compounds, anti aromatic compounds have several resonance structures and some of them are also conjugated ( 1,3-cyclobutene). Why is it that just having 4n electrons makes them ...
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27 views

Resonance in phenoxide anion [duplicate]

Why is resonance possible in phenoxide anion as when the electron pair of oxygen is involved in conjugation we have 4 pairs of electrons in resonance which should imply that the ring has become anti ...
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23 views

Mesomeric structures in aromatic compounds

Can electrons be transferred to a neutral atom as in resonance of C6H5OH. here double bond transfers electrons to c of ch and c gets negative charge. while in other compounds of benzene rigs electrons ...
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1answer
64 views

Friedel-Crafts alkylation of five-membered heterocycles

The five-membered heterocycles pyrrole, furan, and thiophene undergo Friedel-Crafts acylation, but I have not seen them undergoing a simple Friedel-Crafts alkylation reaction with a Lewis acid such as ...
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33 views

Basicity of heterocyclic compounds

Pyrrol, furan or thiophene don't have any bond pair electrons free to release which is why they shouldn't be basic, but the lecturer of organic chemistry is saying that they are basic as they react ...
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1answer
64 views

Synthesis of indigo from anthranilic acid - reaction not taking place

I was trying to synthesise indigo via the Heumann indigo synthesis (II.), which involves heating antrhanilic acid and chloroacetic acid, both dissolved in isopropanol. After heating up, a hydroxide or ...
3
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1answer
49 views

Formation of Tropylium carbocation

I've read that Tropylium carbocation is formed by the ring expansion of benzyl carbocation. But in benzyl carbocation, the $\ce{C}$ atoms in the benzene ring are $sp^2$ hybridized i.e. $120^\circ$ is ...
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2answers
77 views

Most acidic compound amongs the following unsaturated ketones?

In the given picture, I know that the most acidic will be (a), because of potential of ring expansion. I tried a few times but wasn't able to get a satisfactory six membered ring. I think (a) is the ...
3
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1answer
77 views

Why does selenophene not undergo aromatic substitution?

Other derivatives like thiophene, pyrrole give electrophilic substitution but why not selenophene? Is it because selenophene does not have enough electron donating effect and not having its electrons ...
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131 views

Are graphite and boron nitride aromatic

Are graphite and boron nitride aromatic? Graphite has a planar network of $6$-membered rings with each carbon connected to three other carbons. Since the valency of carbon is not satisfied, there ...
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29 views

Determining where a group will direct an addition

I'm looking at a phenol with a ketone in one of the meta positions being treated with $$ \frac{Cl_2}{AlCl_3} $$ I know the Alcohol is the stronger activator because ketone is a deactivator. I'm ...
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21 views

Which catalyst should I use? [closed]

What is the catalyst should I use in the reaction of halogenation " electrophilic substitution reaction" of Benzene? Fecl3 or FeBr3 ? And why?
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2answers
242 views

Comparing the reactivity towards aromatic electrophilic substitution reaction

In the following pairs of molecules, which is more reactive towards electrophilic substitution reaction? 1) 1,4-dinitrobenzene or 1,3-dinitrobenzene (don't consider the ortho isomer) 2) ...
6
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1answer
111 views

Why is imidazole considered an electron deficient heterocycle?

The paper I'm looking at mentions electron deficient heterocycles such as (di)azines, benzothiazole and imidazole. Can you tell me the criteria to determine whether a heterocycle is electron ...
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2answers
77 views

How is it possible that meta xylene exists?

Methyl group is ortho para directing so it should direct the second methyl group to ortho or para position giving rise to ortho or para xylene but how can meta xylene be formed?
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44 views

Numbering in chlordiazepoxide

The IUPAC name of chlordiazepoxide is given as : 7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine-4-oxide, but when I started numbering the structure, I am unable to find chlorine on 7th carbon, ...
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2answers
137 views

Synthesising Complex Aromatic Compound

I have to synthesis the above compound using only toluene as the carbon source. I have never done something like this before and I have no clue on how to start. I am even more confused by the fact ...
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1answer
60 views

Simpler synthesis?

I have to obtain 1-nitro-2,4,5-triaminobenzene from 1,3-dichlorobenzene. I have thought of: Reaction with $\ce{Mg}$ Rc with $\ce{CO2}$, then $\ce{H2O}$. By this point I have izophthalic acid. ...
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1answer
215 views

IUPAC nomenclature for an interesting looking organic compound

How can I name this organic compound while adhering to the IUPAC standards? Excuse me for the terribly hand-drawn hexagons. (Here, the hexagon with the circle in it is essentially a phenyl ...
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1answer
50 views

Aromatic Apparent Substituion Reaction Mechanism

The first molecule reacts with $\ce{NaOH}$ to form the second molecule. I am told that it does't undergo via a substitution mechanism. I am asked to draw the mechanism for it. I am thinking ...
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61 views

Are we wrong about Bakelite formation mechanism?

In the reaction of phenol with acetyl chloride the oxygen of the phenol attacks the acetyl chloride. In Bakelite formation we know that pi electrons attack the carbonyl carbon of formaldehyde.My ...
3
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1answer
57 views

O-carboxylation in the Kolbe-Schmitt reaction

In the Kolbe-Schmitt reaction, we know that the pi electrons of the benzene ring attack the carbon in carbon dioxide, but why doesn't the reaction occur on oxygen instead (as shown in the diagram ...
8
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1answer
85 views

Bromination of Benzene Based Molecule

Using two equivalents of $\ce{Br2}$ and catalytic $\ce{FeBr3}$ compound A can be converted into B. In the same reaction vessel but in multiple steps the conversion of B into C ($\ce{C11H12Br3I}$) ...
3
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1answer
81 views

Zero dipole moment of p-dinitrobenzene

Why is $\mu=0$ for p-dinitrobenzene ? How can the dipole moments of the two Nitro groups exactly cancel each other ? Shouldn't it have a non-zero, albeit feeble, dipole moment ?
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55 views

Question about Anti-Aromatic and Non-Aromatic compounds

Why can't just all anti-aromatic systems loose planarity (and hence conjugation) and be non-aromatic like cyclooctatetraene ? ...
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1answer
54 views

A question about preparation of chlorobenzene

The best method (as I have read) for preparation of chlorobenzene is by reacting it with $\ce{Cl2}$/$\ce{FeCl3}$. Why its not the best practice to react phenol with $\ce{PCl5}$ ?
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1answer
62 views

How do I convert 4-(Methylthio)benzaldehyde to 4-(thioacetate)benzaldehyde?

Sorry if I have the incorrect name of the final product. I'm trying to acylate the methyl mercaptan substituent to a thioester (thioacetate). I appreciate any help!
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Kinetic Isotopic Effect in EAS

It is observed that rate of reaction of two isotopologues of benzene, $\ce{C6D6}$ and $\ce{C6H6}$, is the same for electrophilic aromatic reactions, as the deprotonation is not the rate limiting step. ...
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1answer
59 views

Aromaticity & delocalization of electrons

Are these Anti aromatic/aromatic or non aromatic? 1. Here, if we were to consider the resonating structure(s) with charge separation One ring is aromatic and other is anti aromatic, and ...
4
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1answer
171 views

How to identify the number of pi electrons in a conjugated system to calculate the HOMO-LUMO gap with the particle in the box approach?

It's my understanding that for a particle in a 1-D box, the change in energy from the HOMO to LUMO can be approximated with the following equation: $$\Delta E=\frac{h^2 ( N + 1 )}{8 m_\mathrm{e} ...
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114 views

Stability of the phenoxide ion

The phenoxide ion is more stable than the phenol itself because of its more stabilized resonance structures. On the other hand, however, we say phenoxide ions are more susceptible to electrophilic ...
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1answer
92 views

Pyridine-N-oxide - Removal of oxygen

Under what condition do the reaction proceed with sole removal of oxygen in contrast with the product also ending up with chlorine substituent? I'm familiar with both reaction mechanism, but can't ...
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2answers
79 views

Halogen and inductive effect

background : As proved by rate of EAS, mesomeric or simply conjugated resonance is weaker for halogens than inductive and make them electron taking, with fluorine almost doing nothing due to ...
0
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1answer
61 views

Is chloronitrobenzene and nitrochlorobenzene same?

Is it 2-chloronitrobenzene or 2-nitrochlorobenzene? If we take nitro group as the substituent, it will be 2-chloronitrobenzene. But if we take chloro group as the substituent, it is ...
0
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1answer
27 views

What is exactly ortho effect in Reimmer-Timmer reaction? [duplicate]

In the Reimmer-Timmer reaction cho group is added to only at ortho position not at para position , I got the answer for this as ortho effect. So what is exactly ortho effect.
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116 views

The naming of benzene

Why is benzene not called as a cyclo triene? Wikipedia says benzene is a IUPAC name, but isn't it a common name?
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2answers
339 views

Does Friedel-Crafts Reaction fail with Benzoic acid?

I know that Friedel-Crafts reaction (Either alkylation or acylation) fails with phenol and aniline due to formation of a coordinate bond between lewis acid catalyst and lone pairs of them. But I ...
4
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1answer
98 views

Nucleophilic substitution mechanisms in aromatic compounds

I was reading nucleophilic substitution in Aromatic halides and it suggests two different mechanisms namely - SNAr and benzyne mechanism. However, I am confused between which one to use when trying to ...
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1answer
130 views

What is the use of “pyro” in the naming of organic compound?

Recently I asked a question on the naming of polyhydroxy phenols. One of them was pyrogallol (1,2,3-Trihydroxybenzene) which is synthesized from gallic acid obtained from oak galls. (BEWARE- not a ...
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657 views

Why is this compound named resorcinol?

Substituted phenols or polyhydroxy phenols have their general name apart form IUPAC names. The general names comes from the source it is found like:- Catechol (1,2-dihydroxybenzene)- obtained from ...
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Suggestions for reaction conditions to prepare methyl 2,4,6-trimethylbenzenesulfonate

I'm a beginner in organic chemistry and I wish to produce methyl 2,4,6-trimethylbenzenesulfonate. My reactants are 2,4,6-trimethylbenzenesulfonyl chloride (solid crystals) and methanol (solvent as ...