Question

Write the structure and IUPAC name of the following compounds.
(i) $\alpha$-chloropropionaldehyde
(ii) $\beta$-hydroxybutyraldehyde
(iii) isobutyraldehyde
(iv) $\beta$-methyl valeraldehyde
(v) isopropyl methyl ketone
(vi) diisopropyl ketone
(vii) m-bromobenzaldehyde
(viii) dibenzyl ketone
(ix) divinyl ketone
(x) allyl methyl ketone
(xi) ethyl phenyl ketone
(xii) n-butyrophenone

Answer 1

$\alpha {\text{ and }}\beta$ shows the relative positions of the substitutions from the main carbon. If the main carbon is given first number, then $\alpha$ position shows second number position and $\beta$ position shows third number position.

Complete Step-by-Step Solution:
We will give IUPAC name and chemical structure to the given compounds one by one.
(i) $\alpha$-chloropropionaldehyde :
- Here, $\alpha$ shows the next carbon to the number 1 carbon in the compound. So, it is the place where the chloro group is attached. So, its structure can be given as

- We know that we use –al suffix for aldehydes. So, its IUPAC name will be 2-chloropropanal.
(ii) $\beta$-hydroxybutyraldehyde :
- $\beta$ shows that the hydroxyl group is at third carbon of aldehyde. So, its chemical structure will be

- The IUPAC name of this compound will be 3-chloropropanal
(iii) isobutyraldehyde
- iso- prefix indicates that there is a methyl group at the second last carbon of the chain. So, its structure can be given as

- We can name give IUPAC name of this compound as 2-methyl propanal
(iv) $\beta$-methyl valeraldehyde
- Valera- prefix shows the presence of a total five carbons in the chain. So, the structure can be given as

-The IUPAC name of this compound is 3-methyl pantanal
(v) isopropyl methyl ketone
- There is an isopropyl and methyl group attached to the carbonyl group. Its structure can be given as

- In IUPAC nomenclature of ketones, we can use –one suffix. So, the IUPAC name of this compound will be 3-methyl butan-2-one.
(vi) diisopropyl ketone
- Here, two isopropyl groups are there. So, its structure is

- The IUPAC name of this compound is 2,4-dimethyl pentan-3-one.
(vii) m-bromobenzaldehyde
- m shows meta position and it corresponds to 3-position in the benzene ring. So, its structure is

- The IUPAC name of this compound is 3-Bromo benzaldehyde
(viii) dibenzyl ketone
- Here, two benzyl groups are attached to the carbonyl group. The structure can be given as

- The IUPAC name of the compound will be 1,3-diphenyl propanone
(ix) divinyl ketone
- Two vinyl groups are attached to carbonyl carbon here. It structure can be given as

- The IUPAC name of this compound can be given as pentan-1,4-diene-3-one.
(x) allyl methyl ketone
- Here one allyl group and one methyl group is there. It structure can be given as

- The IUPAC name of this compound can be given as pentan-1-ene-4-one.
(xi) ethyl phenyl ketone
- Here, one ethyl and one phenyl group is there. So, its structure can be given as

- The IUPAC name of this compound is 1-phenyl propan-1-one.
(xii) n-butyrophenone
- It is a simple ketone involving a butyl group and one phenyl group. Its structure can be given as

- Its IUPAC name can be given as 1-phenyl butan-1-one.

Note: Remember that in the common names of ketones, if ‘ketone’ word is not there, then the substituent group contains the carbonyl carbon. We can take the other functional groups present in the compound as substituent.