Why this compound is named 2-Chloro-4-methylanisole and not 1-Chloro-3-methylanisole ? (See image)

Why naming you should consider the most prior group to be numbered as 1 so if you are considering the ring s anisole then oh CS3 group should be number is 1 and rest all will be substituents and then chlorine will be numbered  2 you have the same name 2 chloro 4 methyl anisole

HELLO THERE!

 

While numbering the carbons in an organic compound to name it, you must be assured that the group of highest priority must get the lowest number.

 

In the above organic compound, we have a Methoxy group attached to a Benzene ring. A methyl group and a Cl is also attached to the benzene ring. Now, on the basis of priority of functional groups, Methoxy comes before Cl group and Methyl group, so the OCH₃ must get number 1. (We know that the common name of Ph-OCH₃ is Anisole, where Ph = Phenyl group).

So, Anisole becomes the main group and Cl and methyl are derivatives. If you number along right side, Cl gets number 2, CH₃ group gets the number 4 and we also cover a double bond, but if you number along the left side, we get CH₃ in 4^th position, but Cl in 6^th, so this way of numbering is wrong.

 

Hence, the name of the compound is 2-chloro-4-methyl anisole.