Animated Solution for Chemistry - Organic Chemistry: The IUPAC name of the following compound is

Imagine you are a detective trying to identify a suspect. In organic chemistry, the IUPAC nomenclature system is our fingerprinting tool. The very first step in naming any organic compound is to identify all the functional groups present in the molecule.

Looking at our given structure, we can spot two distinct functional groups: a carboxylic acid group ($-\text{COOH}$) on the far right, and a hydroxyl group ($-\text{OH}$) attached to the middle of the carbon chain.

Priority Rules

Now, we have a conflict. Which functional group gets to dictate the suffix of the parent name? This is where the IUPAC priority order comes into play. According to the rules, the carboxylic acid group ($-\text{COOH}$) sits at the very top of the priority list, outranking almost all other functional groups, including the hydroxyl group ($-\text{OH}$).

Therefore, $-\text{COOH}$ becomes our principal functional group, and it will determine the suffix of our compound. The $-\text{OH}$ group, having lost the battle, is demoted to a mere substituent and will be indicated by the prefix "hydroxy".

With our principal functional group identified, the next step is to find the longest continuous carbon chain. However, there is a strict condition: this chain must include the carbon atom of the principal functional group.

Starting from the carbon of the $-\text{COOH}$ group and tracing along the longest path, we count exactly 5 carbon atoms. A 5-carbon chain gives us the word root "pent". Since all the carbon-carbon bonds in this chain are single bonds, our primary suffix is "-an".

Now, we need to number our carbon chain. The golden rule here is to give the lowest possible locant (number) to the principal functional group. Thus, we assign the number 1 to the carbon atom of the $-\text{COOH}$ group and continue numbering towards the left:

1. ${\text{C}}_1$: $-\text{COOH}$ carbon 2. ${\text{C}}_2$: $-{\text{CH}}_2-$ 3. ${\text{C}}_3$: $-\text{CH}(\text{OH})-$ 4. ${\text{C}}_4$: $-\text{CH}({\text{CH}}_3)-$ 5. ${\text{C}}_5$: $-{\text{CH}}_3$

Let's locate our substituents on this numbered chain. We have a hydroxyl group at position 3 and a methyl group at position 4.

Finally, we assemble the complete IUPAC name. When writing the prefixes for the substituents, we must list them in alphabetical order. Comparing "hydroxy" and "methyl", 'h' comes before 'm'.

So, our prefix becomes 3-hydroxy-4-methyl.

Combining this with our word root ("pent"), primary suffix ("-an"), and secondary suffix ("-oic acid"), we get the final, elegant name: