Name the following aldehydes and ketones:

SOLUTION:

Molecule 1.

1. Main chain: 5 carbons (pentane)
2. Numbering: Start at the aldehyde (functional group)
Functional group: aldehyde
3. Name: Pent-3-ynal

Molecule 2.

1. Main chain: 3 carbons (propane)
2. Numbering: lowest locant to aldehyde.
3. Functional group: aldehyde
4. Substituents: 2-methyl.
5. Name: 2-Methylpropanal


Aldehydes and ketones take precedence over alkenes and alkynes, and are numbered by giving them the lowest locant.

Molecule 3.

1. Main chain: 3 carbons (propane)
2. Functional group: aldehyde (dialdehyde)
3. Name: Propanedial

Molecule 4.

1. Main chain: 6 carbons (hexane)
2. Functional group: ketone
3. Numbering: Assign the smallest locant to the ketone
4. Substituents: 5-hydroxy.
5. Name: 5-Hydroxyhexan-2-one

Molecule 5.

1. Main chain: 4 carbons (butane)
2. Functional group: aldehyde
3. Numbering: Assign the smallest locant to the aldehyde
4. Name: But-3-ynal

Molecule 6.

1. Main chain: 5-membered cycle (cyclopentane)
2. Functional group: ketone
3. Numbering: start at the ketone and work your way up to the substituent
4. Substituents: 3 -methoxy .
5. Name: 3-Methoxycyclopentanone

Molecule 7.

1. Main chain: 6 carbons (hexane)
2. Functional group: aldehyde (dialdehyde)
3. Numbering: Start at the end that gives the phenyl the lowest locant.
4. Substituents: 3 -phenyl.
5. Name: 3-Phenylhexanedial

Molecule 8.

1. Main chain: 6 carbons (hexane)
2. Functional group: aldehyde
3. Numbering: Assign the smallest locant to the aldehyde
4. Substituents: 5-hydroxy and 4-oxo .
5. Name: 5-Hydroxy-4 -oxohexanal


Aldehydes take priority over ketones, which are renamed as substituents (oxo-)

Molecule 9.

1. Main chain: 6-membered cycle (cyclohexane)
2. Functional group: aldehyde (-carbaldehyde )
3. Numbering: minor locant to the -CHO group (this is not numbered)
4. Substituents: ketone ( oxo-) in 3
5. Name: 3-Oxocyclohexanecarbaldehyde

Molecule 10.

1. Main chain: 3 carbons (propane)
2. Functional group: aldehyde (dialdehyde)
3. Substituents: methyls at 2,2 .
4. Name: 2,2-Dimethylpropanedial

Molecule 11.

1. Main chain: 4 carbons (butane)
2. Functional group: aldehyde
3. Substituents: 3 -formyl
4. Name: 3-Formylbutanedial

Molecule 12.

1. Main chain: 4 carbons (butane)
2. Functional group: aldehyde
3. Numbering: Assign the smallest locant to the aldehyde
4. Substituents: 4-hydroxy and 3-oxo .
5. Name: 4-Hydroxy-3-oxobutanal