Directing Groups Flashcards
What is the outcome of phenol undergoing an electrophilic substitution reaction with nitric acid?
Formation of 2-nitrophenol and 4-nitrophenol
These are the two isomers produced from the reaction.
How do substituted aromatic compounds compare to benzene in terms of electrophilic substitution?
Some undergo disubstitution more readily, while others require extreme conditions
This variation affects the reactivity of different substituted aromatic compounds.
What catalyst is required for bromine to react with benzene?
A halogen carrier catalyst
This is necessary for the electrophilic substitution reaction to occur.
How does phenylamine react with bromine compared to benzene?
Phenylamine reacts rapidly with bromine
This indicates that the -NH2 group activates the benzene ring.
What is the reactivity of nitrobenzene with bromine?
Reacts slowly, requiring a halogen carrier catalyst and high temperature
The -NO2 group deactivates the aromatic ring.
How does the -NH2 group affect the electrophilic substitution on the benzene ring?
It activates the ring, making it more reactive with electrophiles
This leads to a higher rate of reaction compared to benzene.
What effect does the -NO2 group have on the benzene ring?
It deactivates the ring, making it less reactive with electrophiles
This results in a slower reaction rate compared to benzene.
What differences exist between the rate and position of substitution in the examples of -NH2 and -NO2 groups?
Different rates of reaction and different positions of substitution
The -NH2 group leads to more rapid substitution compared to the -NO2 group.
What are the two types of directing groups in relation to a benzene ring?
Ortho and para-directors; meta directors
Ortho and para-directors are also known as 2- and 4-directing groups, while meta directors are referred to as 3-directing groups.
Which groups are considered activating groups?
2- and 4-directing groups, with the exception of halogens
Activating groups enhance the reactivity of the benzene ring towards electrophilic substitution.
What type of groups are 3-directing groups classified as?
Deactivating groups
Deactivating groups reduce the reactivity of the benzene ring towards electrophilic substitution.
In organic synthesis, why is the directing effect of substituent groups important?
It helps in planning the order of electrophilic substitution reactions
The correct order is essential to achieve the desired substitution pattern and final product.
True or False: All 2- and 4-directing groups are deactivating groups.
False
All 2- and 4-directing groups are activating groups, while all 3-directing groups are deactivating.
Fill in the blank: All 3-directing groups are _______.
[deactivating groups]
This classification indicates a reduced reactivity towards electrophilic substitution.
What must be considered when carrying out multiple electrophilic substitution reactions on an aromatic compound?
The order in which the reactions are carried out
This ensures the correct substitution pattern and the preparation of the required product.
2-4 directing groups
NH2
NHR
OR
R
C6H5
F Cl Br I
3 directing groups
RCOR
COOR
SO3H
CHO
COOH
CN
NO2
NR3+
