Q4-4-1P - Organic Chemistry (Mcmurry)

Question

Give IUPAC names for the following cycloalkanes

Step-by-Step Solution

Answer

a) 1,4 dimethyl cyclohexane

b) 1-methyl,3-propyl cyclopentane

c) 3-cyclobutyl pentane

d) 1-bromo,4-ethyl cyclodecane

e) 1-isopropyl,2-methyl cyclohexane

f) 4-bromo,1-tert-butyl,2-methyl cycloheptane

IUPAC nomenclature

It is a method to give a scientific name to the organic compounds recommended by the Indian Union of Pure and Applied Chemistry.

Nomenclature of cycloalkanes

IUPAC rules used for naming of cycloalkanes

• Name the parent cycloalkane 
• Assign numbering to the substituents
• Assign the first number to the bulky group
• Halogens get the first priority
• Write the name of the molecule in alphabetic

Naming of cycloalkane a,b,c

a.

1. The parent cycloalkane is cyclohexane 
2. Bothe the same substituent that is methyl 
3. Position of methyl is 1and 4
4. So, the IUPAC name is 1,4 dimethyl cyclohexane

b.

1. The parent cycloalkane is cyclopentane 
2.  The substituent are propyl and methyl
3. Position of methyl is 1and propyl 3 
4. So, the IUPAC name is -methyl,3-propyl cyclopentane

c.

1. The parent alkane is pentane because alkane chain is longer than cyclo group
2.  The substituent are cyclobutyl
3. Position of cyclobutyl is 3 
4. So, the IUPAC name is 2-cyclobutyl pentane

Naming of cycloalkane d,e,f

d.

1. The parent cycloalkane is cyclodecane
2.  The substituents are ethyl and bromo
3. Position of bromo is 1 and ethyl is 4
4. So, the IUPAC name is 1-bromo,4-ethyl cyclodecane

e.

1. The parent cycloalkane is cyclohexane
2.  The substituents is methyl and isopropyl
3. Position of isopropyl is 1 and methyl is 2

So, the IUPAC name is 1-isopropyl,2-methyl cyclohexane

f.

1. The parent cycloalkane is cycloheptane
2.  The substituent are bromo, tert-butyl and methyl
3. Position of 1-tert butyl ,4-bromo,2-methyl
4. So, the IUPAC name is 4-bromo,1-tert-butyl,2-methyl cyclohexane