Question

What is the IUPAC name of the compound listed below.
$C{{H}_{3}}-CH\left( C{{H}_{3}} \right)-CH\left( {{C}_{6}}{{H}_{5}} \right)-N{{H}_{2}}$
A. $\text{1-Amino-1-phenyl-2-methyl propane}$
B. $\text{2-Methyl-1-phenyl propan-1-amine}$
C. $\text{2-Methyl-1-Amino-1-phenyl propane}$
D. $\text{1-isopropyl-1-phenyl methyl amine}$

Answer 1

Hint: There are a large number of organic compounds. To remember all the common names of organic compounds was a difficult task. So, there was a need for some rules which could assign a systematic name to the organic compound, so that we clearly identify them. Therefore, a systematic method of naming organic compounds was developed known as IUPAC system of nomenclature.

Complete step-by-step answer:The compound given to us in the question is $C{{H}_{3}}-CH\left( C{{H}_{3}} \right)-CH\left( {{C}_{6}}{{H}_{5}} \right)-N{{H}_{2}}$and we have to write its IUPAC names.
Let us see all the rules step by step to write the IUPAC name of an organic compound containing a functional group.
Step 1: Identify the parent chain. Parent chain is that carbon chain which includes the functional group without caring whether it also denotes the longest possible carbon chain or not.
For instance, in the given compound in this question, the longest carbon chain consists of 3 carbon atoms. So, it should be propane.
Step 2: Next step is to identify the functional group. In the given structure, if we recall the different types of functional groups, we can clearly see that the given compound has $\left( -N{{H}_{2}} \right)$as a functional group which belongs to the Amine class of compounds. And this functional group is attached to the first carbon atom.
Step 3: Next identify whether any other substituents are present in the compound or not. In this compound phenyl $\left( {{C}_{6}}{{H}_{5}} \right)$and methyl are present as a substituent.
Step 4: Combine all the information and write the IUPAC name.
In this question, we know the main chain is propane. A phenyl group as a substituent is attached at first carbon and methyl group at second carbon. Also, the compound consists of a functional group of amine class at first carbon.
Hence, the IUPAC name considering the alphabetical arrangement of names will be as follows:$\text{2-Methyl-1-phenyl propan-1-amine}$

Hence, the correct option is option B.

Note:When organic compounds have more than one functional groups, then one of these is considered as principal functional group while others are treated as substituents. The primary functional group is named by adding its suffix whereas the other functional groups treated as substituents are prefixed. The choice of principal functional group is made on the basis of order of preference.
The following is the decreasing order of priority of some functional groups.
$\left( -COOH \right)>\left( -S{{O}_{3}}H \right)>\left( -COOR \right)>\left( -COCl \right)>\left( CON{{H}_{2}} \right)>\left( -CN \right)>\left( -HC=O \right)>\left( C=O \right)>\left( OH \right)$