What is a synthetic route in organic chemistry?

A substitution reaction is a reaction in which an atom or group of atoms in a molecule is replaced by a different atom or group of atoms.

When designing a synthesis, if the target molecule contains .......... carbon atoms than the starting material, one method to extend the chain is to introduce a .......... group via nucleophilic substitution, which adds .......... carbon atom(s).

When designing a synthesis, if the target molecule contains more carbon atoms than the starting material, one method to extend the chain is to introduce a nitrile (–CN) group via nucleophilic substitution, which adds one carbon atom(s).

True or False? A synthesis route with more steps is always preferred because it allows for greater control over the product.

False. Fewer steps are preferred because each additional step wastes materials and energy and reduces overall yield. Efficiency and sustainability are key principles of green chemistry.

State the reagents and conditions to convert a halogenoalkane into a primary amine.

Concentrated ammonia (NH 3 ), heated under pressure. The mechanism is nucleophilic substitution.

To convert a primary alcohol to a carboxylic acid, the reagent is .......... under .......... conditions. The alcohol is first oxidised to an .......... and then oxidised further.

To convert a primary alcohol to a carboxylic acid, the reagent is K 2 Cr 2 O 7 / H 2 SO 4 under heat under reflux conditions. The alcohol is first oxidised to an aldehyde and then oxidised further.

True or False? Aromatic nitration uses concentrated HNO 3 and H 2 SO 4 at temperatures below 55°C via an electrophilic substitution mechanism.

True. Cold concentrated H 2 SO 4 protonates HNO 3 to generate the nitronium ion (NO 2 + ), which acts as the electrophile in the electrophilic substitution reaction. The temperature is kept below 55°C to prevent di-nitration.

What are the reagents and conditions to reduce a nitrile to a primary amine?

LiAlH 4 in dry ether, with heat. This is a reduction reaction that converts –CN into –CH 2 NH 2 .

A LevelChemistryAQAFlashcardsAdvanced Organic ChemistryOrganic Synthesis

Organic Synthesis (AQA A Level Chemistry): Flashcards

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What is a synthetic route in organic chemistry?

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What is a synthetic route in organic chemistry?
A substitution reaction is a reaction in which an atom or group of atoms in a molecule is replaced by a different atom or group of atoms.
When designing a synthesis, if the target molecule contains .......... carbon atoms than the starting material, one method to extend the chain is to introduce a .......... group via nucleophilic substitution, which adds .......... carbon atom(s).
When designing a synthesis, if the target molecule contains more carbon atoms than the starting material, one method to extend the chain is to introduce a nitrile (–CN) group via nucleophilic substitution, which adds one carbon atom(s).
True or False?
A synthesis route with more steps is always preferred because it allows for greater control over the product.
False.
Fewer steps are preferred because each additional step wastes materials and energy and reduces overall yield. Efficiency and sustainability are key principles of green chemistry.
State the reagents and conditions to convert a halogenoalkane into a primary amine.
Concentrated ammonia (NH₃), heated under pressure.
The mechanism is nucleophilic substitution.
To convert a primary alcohol to a carboxylic acid, the reagent is .......... under .......... conditions. The alcohol is first oxidised to an .......... and then oxidised further.
To convert a primary alcohol to a carboxylic acid, the reagent is K₂Cr₂O₇ / H₂SO₄ under heat under reflux conditions. The alcohol is first oxidised to an aldehyde and then oxidised further.
True or False?
Aromatic nitration uses concentrated HNO₃ and H₂SO₄ at temperatures below 55°C via an electrophilic substitution mechanism.
True.
Cold concentrated H₂SO₄ protonates HNO₃ to generate the nitronium ion (NO₂⁺), which acts as the electrophile in the electrophilic substitution reaction. The temperature is kept below 55°C to prevent di-nitration.
What are the reagents and conditions to reduce a nitrile to a primary amine?
LiAlH₄ in dry ether, with heat.
This is a reduction reaction that converts –CN into –CH₂NH₂.

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