Chapter 19, Problem 29PE

(a)

Interpretation Introduction

Interpretation:

IUPAC name of given below compound has to be given.

    

Concept introduction:

IUPAC Nomenclature:

IUAC gives rules for the naming of chemical compounds. These rules are,

For unsaturated hydrocarbons, longest chain is the parent chain of the compound and remaining groups and atoms are consider as substituent.

In the nomenclature, Find the parent chin first then number the carbon atoms in the parent chain by giving lest number to the unsaturated double/triple bonded carbon followed by designate the substituent in its position in parent chain.

If more than one same substituent were occurs, add a prefix (di-, tri-, tetra-, ect..) in front of parent chain name.

If compound contains double bond means, name end with suffix of ene or if compound contains triple bond means name end with suffix of yne.

Finally the systematic name was written as, the substituent position number with prefix (di-, tri-, tetra-, ect..) of number of substituents followed by name of the substituent then write the parent chain name (which contains large number of carbon atoms in the chain) with suffix of suffix ene/yne.

The parent chain names based on the carbon atoms are,

$\begin{array}{l}\text{Alkenes}\\ {\text{CH}}_2{\text{=CH}}_2\text{Ethene}\\ {\text{CH}}_2{\text{=CH-CH}}_3\text{Propene}\\ {\text{CH}}_2{\text{=CH-CH}}_{\text{2}}{\text{-CH}}_3\text{Butene}\\ {\text{CH}}_2{\text{=CH-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}{\text{CH}}_3\text{Pentene, etc}\mathrm{..}.\end{array}$          $\begin{array}{l}\text{Alkyne}\\ \text{CH}\equiv \text{CH }\text{Ethyne}\\ \text{CH}\equiv {\text{C-CH}}_3\text{Propyne}\\ \text{CH}\equiv {\text{C-CH}}_{\text{2}}{\text{-CH}}_3\text{Butyne}\\ \text{CH}\equiv {\text{C-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}{\text{CH}}_3\text{Pentyne, ect}\mathrm{...}\end{array}$

The substituent names based on the carbon atoms are,

$\begin{array}{l}{\text{CH}}_{\text{3}}\text{-}\text{methyl}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}\text{- }\text{ethyl}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}\text{propyl}\end{array}$

Explanation of Solution

IUPAC name of given compound is,

Parent chain name of given compound is 2-hexene,

From the structure given structure, methyl group is present at third carbon so substitution name is 3-methyl.

Combine the substituent name followed by parent name to get complete name of the compound.

Hence, the complete IUPAC name of the compound is,

(b)

Interpretation Introduction

Interpretation:

IUPAC name of given below compound has to be given.

    

Concept introduction:

Refer part (a).

Explanation of Solution

IUPAC name of given compound is,

Parent chain name of given compound is 2-butene,

From the given structure, two methyl groups are present at 2 and 3 carbon atom of parent chain so substitution name is 2,3-dimethyl.

Combine the substituent name followed by parent name to get complete name of the compound.

Hence, the complete IUPAC name of the compound is,