Question

The IUPAC name of the given structure is:

a.) 5-bromo-6-chloro-1-cyclohexen-3-yne
b.) 6-bromo-5-chlorocyclohexen-3-yne
c.) 6-bromo-5-chloro-3-cyclohexen-1-yne
d.) 4-bromo-3-chloro-1-cyclohexene-5-yne

Answer 1

Hint: To write the IUPAC nomenclature we have to understand the compound structure and the functional group attached to it. For the IUPAC naming of compounds there are certain rules to be followed. The IUPAC nomenclature is a step wise rule to name the compound.

Complete Solution :
IUPAC stands for international union for pure and applied chemistry ach the steps to write the IUPAC nomenclature are mentioned below:
Step 1- select the longest carbon chain – the longest carbon chain in the given compound is cyclohexane. Hexane means 6 carbon atoms joined together with a single bond. This compound contains a double and a triple bond at position 1 and 3 respectively.
Step-2 identifies the substituents attached to the parent chain and number the parent chain from the end which gives the lowest number to the substituent- in the given compound bromine is present at 5 position and chlorine is present at 6 position.

Hence, the IUPAC name of the given compound is:
5-bromo-6-chloro-1-cyclohexen-3-yne.
So, the correct answer is “Option A”.

Note: While writing the IUPAC nomenclature the substituents present in the given compound should be arranged in alphabetical order and if the same substituent occurs more than one then the prefix like di, tri, tetra etc. are used. It is important to put a comma between two numbers and a dash between a number and the name of the substituent. While arranging the substituents in alphabetical order we should ignore the prefix like di, tri, and tetra and arrange on the basis of the first letter of the substituent name.