Why are these names incorrect and what would they be named instead according to IUPAC rules??
Dimethylcyclohexane
2-Ethyl-1-methylcyclopentane
What is wrong with each of the following cycloalkane names using IUPAC rules?
2017-01-17 1:01 am
回答 (1)
2017-01-17 1:28 am
Dimethylcyclohexane is an incorrect IUPAC name.
This is because the position numbers of the two methyl groups are missed.
If the two methyl groups are attached to the same carbon atom, the correct IUPAC name is 1,1-dimethylcyclohexane.
If the two methyl groups are attached to two different carbon atoms, the correct IUPAC name is 1,2-dimethylcycyclohexane, 1,3-dimethylcycyclohexane or 1,4-dimethylcycyclohexane, depending on the positions of the two methyl groups.
2-ethyl-1-methylcyclopentane is an incorrect IUPAC because the first number “2” is NOT the smallest number.
“ethyl” must be in front of “methyl” by alphabetical order. The IUPAC name should be ()-ethyl-()-methylcyclopentane. In this case, the first number should be the as small as possible.
The correct IUPAC name is 1-ethyl-2-methylcyclopentane.
This is because the position numbers of the two methyl groups are missed.
If the two methyl groups are attached to the same carbon atom, the correct IUPAC name is 1,1-dimethylcyclohexane.
If the two methyl groups are attached to two different carbon atoms, the correct IUPAC name is 1,2-dimethylcycyclohexane, 1,3-dimethylcycyclohexane or 1,4-dimethylcycyclohexane, depending on the positions of the two methyl groups.
2-ethyl-1-methylcyclopentane is an incorrect IUPAC because the first number “2” is NOT the smallest number.
“ethyl” must be in front of “methyl” by alphabetical order. The IUPAC name should be ()-ethyl-()-methylcyclopentane. In this case, the first number should be the as small as possible.
The correct IUPAC name is 1-ethyl-2-methylcyclopentane.
收錄日期: 2021-04-18 16:02:31
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