Question

Write the structure of 2-aminotoluene.

Answer 1

Hint: While determining the structure of aromatic compounds there are a set of rules. It involves knowing the word root, what are its substituents attached to the ring. Where are the substituents attached and their priorities.

Complete answer:
While finding the structure of an organic compound from its IUPAC name, there are a set of rules to follow.
-First we have to identify the word root in the name and write its corresponding straight chain or the cyclic compound. Here the word root is toluene. We know the structure of toluene is as shown in the figure below.

-Next we have to check the number of carbon atoms on either end. In this case there are no other carbon atoms present in a chain.
-Check for double bonds present in the name as –ene or –yne. Both are not present. So there are no extra double or triple bonds.
-Now, we need to check for the presence of functional groups. There is an amino group in the name. So, $-N{{H}_{2}}$ is present.
-We have to find where the amino group is present. In the name it is given second position to toluene.
For aromatic compounds (toluene is aromatic) the number system is

Here those mentioned as 2 is the second position just next to the carbon to which the methyl group of toluene is called ortho position (can be represented as o). The third position is called the meta (m) and fourth position is called para (p) position.

Thus, in the name it is given that amino is in second position that is in the ortho position. Therefore, the final structure of 2-aminotoluene is

Note: While deriving a structure for aromatic compounds such as benzene, we need to consider the position to where the functional group is present that is in the ortho, para or meta position in the case of benzene. In case of monosubstituted derivative, the substituent is always at position 1.