Textbook Question
A student was given the structural formulas of several compounds and was asked to give them systematic names. How many did the student name correctly? Correct those that are misnamed.
k. 2-methyl-2-isopropylheptane
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4. Alkanes and Cycloalkanes
IUPAC Naming
1:18 minutesProblem 71b
Textbook Question
Correct the following incorrect names using standard IUPAC nomenclature. [Draw a compound that corresponds to the incorrect name, and then rename it.]
(b) 1,5-dimethylcyclohexane
Verified step by step guidance1
Step 1: Begin by drawing the structure of the compound based on the incorrect name '1,5-dimethylcyclohexane'. Cyclohexane is a six-membered ring, and the name suggests two methyl groups attached at positions 1 and 5.
Step 2: Analyze the structure you have drawn. In cyclohexane, positions 1 and 5 are not adjacent but opposite to each other on the ring. Verify if the numbering follows the lowest locant rule for substituents.
Step 3: Apply the IUPAC nomenclature rules. Check if the numbering of the substituents can be adjusted to provide the lowest possible locants. For example, if the methyl groups are opposite each other, the numbering should start at one substituent and proceed around the ring to minimize the locant numbers.
Step 4: Rename the compound based on the corrected numbering. If the methyl groups are opposite each other, the correct name would likely be '1,4-dimethylcyclohexane' because positions 1 and 4 provide the lowest locants for the substituents.
Step 5: Confirm the corrected name by ensuring it adheres to all IUPAC rules, including the lowest locant rule and proper identification of the parent chain or ring structure.
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1mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
IUPAC Nomenclature
The International Union of Pure and Applied Chemistry (IUPAC) nomenclature is a systematic method for naming organic chemical compounds. It provides rules for naming based on the structure of the molecule, including the longest carbon chain, functional groups, and substituents. Understanding these rules is essential for accurately identifying and renaming compounds.
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Cycloalkanes
Cycloalkanes are saturated hydrocarbons that contain carbon atoms arranged in a ring structure. The naming of cycloalkanes involves identifying the number of carbon atoms in the ring and any substituents attached to it. Recognizing the structure of cycloalkanes is crucial for correcting names and ensuring proper representation of the compound.
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Substituent Positioning
In organic chemistry, substituents are atoms or groups of atoms that replace hydrogen atoms in a hydrocarbon. The position of these substituents on the main carbon chain or ring is indicated by numbers in the compound's name. Correctly identifying and numbering the positions of substituents is vital for accurate nomenclature and for avoiding ambiguity in compound names.
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