Class 11Chemistry1 Organic Chemistry: Classification and Nomenclature of Organic CompoundsNomenclature of organic compounds
MediumStructures and $IUPAC$ names of some hydrocarbons are given below. Explain why the names given in the parentheses are incorrect.
$(a)$ $CH_3-CH(CH_3)-CH_2-CH_2-CH(CH_3)-CH(CH_3)-CH_2-CH_3$
Name: $2,5,6-$Trimethyloctane [and not $3,4,7-$Trimethyloctane]
$(b)$ $CH_3-CH_2-CH(CH_2CH_3)-CH_2-CH(CH_3)-CH_2-CH_3$
Name: $3-$Ethyl$-5-$methylheptane [and not $5-$Ethyl$-3-$methylheptane]
$(a)$ $CH_3-CH(CH_3)-CH_2-CH_2-CH(CH_3)-CH(CH_3)-CH_2-CH_3$
Name: $2,5,6-$Trimethyloctane [and not $3,4,7-$Trimethyloctane]
$(b)$ $CH_3-CH_2-CH(CH_2CH_3)-CH_2-CH(CH_3)-CH_2-CH_3$
Name: $3-$Ethyl$-5-$methylheptane [and not $5-$Ethyl$-3-$methylheptane]
(A) According to the lowest locant rule,the set of locants $2,5,6$ is lower than $3,4,7$. Therefore,$2,5,6-$trimethyloctane is the correct name.
$(b)$ When substituents are at equivalent positions from either end of the chain,the lower number is assigned to the substituent that comes first in the alphabetical order. Since $E$ (Ethyl) comes before $M$ (Methyl),the name $3-$ethyl$-5-$methylheptane is correct.
$(b)$ When substituents are at equivalent positions from either end of the chain,the lower number is assigned to the substituent that comes first in the alphabetical order. Since $E$ (Ethyl) comes before $M$ (Methyl),the name $3-$ethyl$-5-$methylheptane is correct.
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Similar Questions
Give the rules for $IUPAC$ nomenclature for branched alkanes. Explain with an example.
What is the $IUPAC$ name of the following compounds?
$(A)$ $CH_3-CH(CH_3)-CH(OH)-CH(C_2H_5)-CH(OH)-CH_3$
$(B)$ $A$ cyclohexane ring with a $-NO_2$ group at position $1$ and a $-OCH_3$ group at position $3$.
$(A)$ $CH_3-CH(CH_3)-CH(OH)-CH(C_2H_5)-CH(OH)-CH_3$
$(B)$ $A$ cyclohexane ring with a $-NO_2$ group at position $1$ and a $-OCH_3$ group at position $3$.
Medium
View SolutionThe $IUPAC$ name of the compound $CH_3-CH(C_2H_5)-CH=CH-CH_3$ is
Medium
View SolutionMatch the compounds in Column-$I$ with their $\text{IUPAC}$ names in Column-$II$. Column-$I$ (Structure) Column-$II$ ($\text{IUPAC}$ Name) $A$. $3-$Bromocyclohexanol $1$. $2, 5$-Dimethylhexane-$1, 3$-diol $B$. $CH_3-C(Br)=C(CH_3)-CH_2OH$ $2$. $3$-Bromocyclohexanol $C$. $CH_3-CH(CH_3)-CH_2-CH(OH)-CH(CH_2OH)-CH_3$ $3$. $\text{Hex-}1\text{-en-}3\text{-ol}$ $D$. $CH_2=CH-CH(OH)-CH_2-CH_2-CH_3$ $4$. $2$-Bromo-$3$-methylbut-$2$-en-$1$-ol
| Column-$I$ (Structure) | Column-$II$ ($\text{IUPAC}$ Name) |
| $A$. $3-$Bromocyclohexanol | $1$. $2, 5$-Dimethylhexane-$1, 3$-diol |
| $B$. $CH_3-C(Br)=C(CH_3)-CH_2OH$ | $2$. $3$-Bromocyclohexanol |
| $C$. $CH_3-CH(CH_3)-CH_2-CH(OH)-CH(CH_2OH)-CH_3$ | $3$. $\text{Hex-}1\text{-en-}3\text{-ol}$ |
| $D$. $CH_2=CH-CH(OH)-CH_2-CH_2-CH_3$ | $4$. $2$-Bromo-$3$-methylbut-$2$-en-$1$-ol |
Medium
View SolutionGiven below are two statements:
Statement $I$: $IUPAC$ name of $HO-CH_2-(CH_2)_3-CH_2-COCH_3$ is $7-$hydroxyheptan$-2-$one.
Statement $II$: $2-$oxoheptan$-7-$ol is the correct $IUPAC$ name for above compound.
In the light of the above statements,choose the most appropriate answer from the options given below:
Statement $I$: $IUPAC$ name of $HO-CH_2-(CH_2)_3-CH_2-COCH_3$ is $7-$hydroxyheptan$-2-$one.
Statement $II$: $2-$oxoheptan$-7-$ol is the correct $IUPAC$ name for above compound.
In the light of the above statements,choose the most appropriate answer from the options given below:
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