Question

Question #15359

Answer 1

3-methylpentanal

Explanation:

Assume that the structure is `CH_3CH_2CH(CH_3)CH_2CHO`.
This is a kind of aldehyde.

IUPAC names an aldehyde by replacing -e to -al in the name of corresponding alkane.
http://www.ivyroses.com/Chemistry/Organic/Naming-Aldehydes.php

For example, the IUPAC name for `CH_3CHO`(acetaldehyde) is ethanal.

`CH_3CH_3` ethan`color(red)"e"`
`CH_3CHO` ethan`color(red)"al"`

[What is the name of this compound?]
If the compound has no branch, i.e. `CH_3CH_2CH_2CH_2CHO`, its name is pentanal the corresponding alkane is pentane(`CH_3CH_2CH_2CH_2CH_3`).

This compound has a `CH_3-` branch in the third place, counting `-CHO` as the first carbon.

Therefore, the IUPAC name is 3-methylpentanal.
https://pubchem.ncbi.nlm.nih.gov/compound/3-methylpentanal