napstablook
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Why does this ring contraction take place in the following nucleophilic substitution?
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10 votes

This reaction should be leaning towards SN1 because the approach of $\ce{H2O}$ for a back attack to the ABMO of the $\ce{C-Br}$ is heavily hindered since the neighborhood is congested due to the small ...

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Mechanism of reaction of ketones with isoalkanes under conc. sulfuric acid and heat
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7 votes

This was going to be a comment but it got too long. TL;DR: - This is not an answer, rather a justification for why the question is (probably) wrong. This paper (linked by @Rishi) gives us ...

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Is there any specific conditions for Neighbouring group participation?
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7 votes

In the given compound the $\ce{-OH}$ group and the $\ce{-NH2}$ and later $\ce{N2^+}$ group are not in anti position with respect to each other. Equatorial positions in cyclohexane are not anti with ...

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

The problem in ortho-aminobenzoic acid is that the acidic hydrogen of carboxylic group is H-bonded with the lone pair of nitrogen in amino group. As a result it is more difficult to extract it ...

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Why is nitrate anion substituted but bromide anion is not in Von Richter reaction?
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6 votes

The Von-Richter reaction's accepted mechanism is given by- As you can see, this is not a simple case of say, removal of $\ce{NO2-}$ ion, instead it involves removal of $\ce{N2}$ which provides ...

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

α,β-Unsaturated carbonyl compounds, for the most stable intermediate with respect to $\ce{H-}$ ion prefer 1,4-addition. However, $\ce{LiAlH4}$ prefers 1,2-addition over 1,4-addition. This can be ...

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What is the reaction mechanism between acetophenone and ethyl phenylpropiolate to form a 2-pyrone?
5 votes

Your attempted mechanism is correct. There is an active $\ce{\alpha-H}$ in the your final intermediate ($2$ $\ce{-COOEt}$s are present on the carbon (well one of them is attached indirectly, but it ...

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Electrophillic susbtitution of bromine on styrene and cinnamic acid in the presence of FeBr3, a Lewis acid
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5 votes

In electrophilic aromatic substitution the activation energy is very high ( as it should be, since the aryl carbocation transition state is very unstable) The role of $\ce{FeBr_3}$ or any lewis acid ...

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When is Zaitsev product formed in pyrolytic elimination reaction?
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5 votes

Cope elimination is a pericyclic reaction that always prefers syn-elimination. Due to hydroxylamine being a poor leaving group, the reactions often tend to prefer hofmann products. However the reason ...

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Finding the major contributing tautomer of 1-(propan-2-yl)-1,2,3,5-tetrahydro-6H-pyrazolo[3,4-b]pyridin-6-one
5 votes

In keto-enol tautomerism, the equilibrium is mostly towards the keto form, as it should be, since $\ce{C=O}$ is a very strong and stable bond. In some cases however we find that the equilibrium ...

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Can't aluminium chloride do electrophilic substitution as an electrophile?
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4 votes

The reaction wouldn't happen because you forget that $\ce{Cl2}$ is also present in the solution (because $\ce{AlCl3}$ is a strong lewis acid). An acid-base reaction is way faster than an aromatic ...

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Why doesn't pure water conduct when it dissociates?
4 votes

Pure water does conduct as pointed out by the above comments. But it has very less dissociation hence there are very few ions to conduct electricity. you may have heard that $pH$ of pure water is 7. ...

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Why are Terminal Alkynes less reactive than internal alkynes?
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4 votes

The mechanism of hydration is an electrophilic addition and requires polarization of the carbon-carbon triple bond. This task is more difficult compared to case of alkene due to it having more %s ...

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Analysing reaction with chair conformation of substituted cyclohexane
3 votes

Why should we assume that the halogens are in equatorial position? As @Orthocresol pointed out there is probably enough reason (it should be still mentioned as any other conformer may still exist ...

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Mechanism of ring opening of amine combined with formylation
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3 votes

This reaction is very similar to Reimer-Tiemann reaction which also consists of the reagent $CHCl_{3}$ + $NaOH$. The mechanism of that reaction is believed to have dichlorocarbene intermediate too. A ...

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Comparing O−O bond length in hydrogen peroxide and dioxide(2−) ion
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3 votes

The way to tackle this is to look at the lone pair repulsions between the 2 molecules. It is known that $\ce{N-N};$ $\ce{O-O};$ $\ce{F-F}$ single bonds are quite unstable due to lone pair (lp) ...

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Attack of HClO4 to dipropylcycloprop-2-en-1-one
1 votes

Assuming that your end products are correct I think this reaction would proceed in a similar manner to the way it will proceed if you use hot $\ce{KMnO4}$ as a reagent. The reason I think that is ...

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Why is hydrogen peroxide acidic in aqueous solution?
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0 votes

The simple size comparison is not accurate. In hydra-acids you can often draw a correlation between the size and strength of $\ce{H-A}$ bond. However $\ce{H2O2}$ consists of only $\ce{O-H}$ bond with ...

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