Question

Provide IUPAC names for the following compounds.

(a)

(b)

(c)

(d)

(e)

( f)

Short answer

(a)2-methyl butane

(b) 2,2-dimethyl propane

(c) 3-ethyl-2-methyl hexane

(d) 2,4-dimethyl hexane

(e) 3, ethyl-2,2,4,5-tetra methyl hexane

(f)4-tert-butyl-3-methylheptane

Step-by-step solution

IUPAC nomenclature of alkanes

Find the longest continuous chain of carbon atoms, and use the name of this chain as the base name of the compound.

Number the longest chain, beginning with the end of the chain nearest a substituent.

Name the substituent groups attached to the longest chain as alkyl groups. Give the location of each alkyl group by the number of the main-chain carbon atom to which it is attached.

When two or more substituents are present, list them in alphabetical order. When two or more of the same alkyl substituent are present, use the prefixes di-, tri-, tetra-, etc., to avoid having to name the alkyl group twice.

(a)

The longest carbon chain contains four carbon atoms, so this compound is named as butane. Numbering from left to right gives the first branch on C2; numbering from right to left gives the first branch on C3, so we number from left to right. There is one methyl group on C2.

(b)

The longest carbon chain contains three carbon atoms, so this compound is named as propane. Numbering can be done from any side. There are two methyl group on C2.

(c)

The longest carbon chain contains six carbon atoms, so this compound is named as hexane. Numbering from right to left gives the first branch on C2 and second branch on C3. There is one methyl group on C2 and one ethyl group on C3.

(d)

The longest carbon chain contains six carbon atoms, so this compound is named as hexane. Numbering from left to right gives the first branch on C2 and second branch on C4. There is one methyl group on C2 and one on C4.

(e)

The longest carbon chain contains six carbon atoms, so this compound is named as hexane. Numbering from up to down gives two methyl branch on C2 one on C4 and C5 and one ethyl branch on C3.

(f)

The longest carbon chain contains seven carbon atoms, so this compound is named as heptane. One tertiary butyl branch on C4 and one methyl branch on C3.