Question

The IUPAC name for $C{{H}_{3}}C{{H}_{2}}CH(OH)CH=C{{H}_{2}}$
A. 2-methyl butyl alcohol
B. 2-methyl butanol-1
C. Pent-1-ene-3-ol
D. 2-methyl butanol and -2-ol

Answer 1

Recollect the rules of IUPAC Nomenclature. Start by drawing the structure of the given compound. Then mark the longest chain of carbon atoms. Identify the functional groups present in the compound. Then check if the compound is saturated or unsaturated and if there are any substituents present. Finally club all the parts in the order, substituents as prefix followed by root/parent name then saturation/unsaturation and at last, functional group as suffix to get the answer.

Complete step by step answer:
The IUPAC nomenclature of organic compound is a method of organic compounds as commended by the International Union of Pure and Applied chemistry. Every possible organic compound should have a name from which structural formula can be generated. There are some basic principles for naming organic compounds which are as follows:
1. Identification of the parent hydrocarbon chain or root of the compound.

Here, the parent hydrocarbon chain consists of all five carbon atoms. So the root of this compound is ‘pent’. Now, there is an unsaturation and a hydroxyl functional group.
2. In the preference order, give the smallest number to the functional group and multiple bonds present in C-chain.

The functional group -OH received third position from either side. For double bonds, if the numbering starts from left then double both will get fourth position and if numbering starts from right then it will get first position.

So, as it receives the smallest number from right, this numbering is preferred.
3. There are no substituents present in the compound. Therefore now we got root as ‘pent’ then a double bond at first carbon atom, so 1-ene and a hydroxyl group at third carbon atom, so 3-ol.
4. Now just arranging the name in the order ‘prefix-root-suffix-functional group’ we get, Pent-1-ene-3-ol.
So, the correct IUPAC name for the given compound is Pent-1-ene-3-ol.

Therefore, the answer is option C.

Note: Care must be taken while writing IUPAC names like adding proper punctuation while naming the organic compounds. There are some basic rules regarding punctuations. These basic rules are as follows –
- Commas must be placed between numbers. For example- 2 3 becomes 2, 3
- Hyphens must be placed between a number and a letter. For example- 2, 3 dimethylbutane becomes 2, 3-dimethylbutane
- Successive words are merged into one word. For example- dimethylbutane