48 Questions
Why does pyrrole tend to react by electrophilic substitution?
Due to protonation at C-2
What is the reason for electrophilic substitution normally occurring at carbon atoms instead of nitrogen in pyrrole?
Presence of a negative charge on carbon atoms due to delocalization
Why does electrophilic substitution preferentially occur at C-2 in pyrrole?
More stable intermediate from C-2 attack with three resonance structures
What is the result of pyrrole undergoing electrophilic substitution reaction at the 2nd position (C2)?
More stable intermediate
Why is C-2 attack in pyrrole considered more stable than C-3 attack?
Stabilized by three resonance structures
What type of reactions does pyrrole undergo with respect to reduction and oxidation?
Reduction and oxidation reactions
Why are the C-atoms of a pyrrole ring more electron-rich compared to benzene?
Resonance pushes electrons from the N-atom into the ring.
What evidence supports the aromatic character of pyrrole?
All ring bonds in pyrrole are double bonds.
What differentiates the acidic properties of pyrrole from other secondary amines?
Participation of the N lone pair in aromatic sextet.
Why is pyrrole sensitive to strong acids?
Protonation occurs at carbons, not at N.
How does pyrrole react with strong bases such as KOH?
To give salt-like compounds that can be used for alkylation or acylation.
What explains the exceptional lack of basicity in pyrrole compared to pyrrolidine?
Participation of N lone pair in pyrrole's aromatic sextet.
What is the commercial method for synthesizing Pyrrole from Furan?
Passing Furan over ammonia in the presence of Aluminium oxide catalyst at high temperature
How does the reactivity of Pyrrole compare to benzene in electrophilic substitution reactions?
Pyrrole is more reactive than benzene
Which type of reactions does Pyrrole undergo that benzene does not?
Diazotization and Reimer-Tiemann reactions
What effect does the presence of a strong acid have on Pyrrole?
Strong acids affect Pyrrole significantly
Why is Pyrrole considered aromatic?
Due to its cyclic structure with delocalized electrons
What is a unique feature of Pyrrole's reactivity compared to benzene?
Higher reactivity leading to easier substitutions
What is the major amino acid found in cartilage and important for maintaining youthful skin?
Proline
Which compound is used for smoking cessation to relieve withdrawal symptoms?
Nicotine
What is the role of Glycopyrrolate in medical use?
Used in Peptic ulcer
What property of Furan allows it to have a planar ring structure?
Aromaticity
How many non-bonding electrons are present in the furan molecule?
6
What is the hybridization of the carbon atoms in Furan that contributes to its planar structure?
sp2
Why does pyrrole have exceptionally strong acidic properties for a secondary amine?
As a result of the participation of N lone pair in aromaticity.
What characteristic of pyrrole makes it resemble the reactivity of benzene derivatives like phenols and amines?
Participation of N lone pair in aromatic sextet.
What ring bond characteristic in pyrrole contributes to its aromatic character?
Intermediate nature between single and double bonds.
How does resonance affect the electron distribution in pyrrole compared to benzene?
It pushes electrons towards the N-atom into the ring.
Why is pyrrole more reactive than benzene?
As a result of resonance pushing electrons into the ring.
What impact does strong acid have on pyrrole's protonation?
Protonation takes place primarily at the C-atoms.
Which reaction is used to synthesize pyrrole from furan commercially?
Passing furan over ammonia in the presence of an aluminum oxide catalyst at 480-490°C
Which of the following reactions does pyrrole undergo, while benzene does not?
All of the above
What is the major factor contributing to the increased reactivity of pyrrole compared to benzene in electrophilic substitution reactions?
The electron-rich nature of the carbon atoms in pyrrole
Which of the following statements best explains the acidic properties of pyrrole?
The delocalization of electrons in pyrrole stabilizes the conjugate base formed upon deprotonation
What is the effect of strong acids on pyrrole?
Pyrrole is protonated, disrupting its aromaticity
Which of the following reactions does pyrrole undergo with respect to reduction and oxidation?
Both a and c
Which of the following statements best explains why electrophilic substitution in pyrrole preferentially occurs at the C-2 position?
The C-2 position is stabilized by three resonance structures, while the C-3 position is stabilized by only two.
Which of the following reactions is most likely to occur when pyrrole is treated with a strong electrophile?
Electrophilic substitution at the C-2 position
In the electrophilic substitution reaction of pyrrole, what is the initial step that occurs?
Protonation of the C-2 position
Which of the following statements best explains why pyrrole is more reactive towards electrophilic substitution compared to benzene?
Pyrrole has a higher electron density due to the presence of the nitrogen atom.
What is the major product formed when pyrrole undergoes electrophilic substitution followed by further reaction with another pyrrole molecule?
Pyrrole trimer
Which of the following statements best explains why electrophilic substitution in pyrrole typically occurs at carbon atoms rather than at the nitrogen atom?
Substitution at the nitrogen atom would disrupt the aromaticity of the ring.
Which of the following statements about the reactivity of monosubstituted pyrroles is correct?
Monosubstituted pyrroles with electron-withdrawing groups undergo electrophilic substitution more readily than unsubstituted pyrrole.
Which of the following statements best explains the exceptional lack of basicity in pyrrole compared to pyrrolidine?
The lone pair of electrons on the nitrogen atom in pyrrole is delocalized into the aromatic ring system, reducing its availability for protonation.
Which of the following statements best explains why electrophilic substitution in pyrrole preferentially occurs at the 2-position (C-2)?
The 2-position is more electron-rich due to the resonance stabilization of the intermediate cation formed during electrophilic substitution.
Which of the following statements best explains the aromaticity of furan?
Furan follows Hückel's rule for aromaticity, with 6 delocalized π electrons in the ring system.
Which of the following statements best explains the reactivity of pyrrole towards strong acids?
Strong acids cause delocalization of the lone pair of electrons on the nitrogen atom, disrupting the aromaticity of pyrrole.
Which of the following statements best describes the role of the nitrogen atom in the reactivity of pyrrole towards electrophilic substitution?
The nitrogen atom modulates the reactivity of pyrrole towards electrophilic substitution by participating in resonance stabilization of the intermediate cation formed during the reaction.
Explore the synthesis, chemical properties, reactivity, aromatic character, and acidic properties of pyrrole. Learn about electrophilic substitution reactions, reduction, oxidation, and more related to heterocyclic compounds.
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