Cycloalkanes are a class of organic compounds characterized by one or more carbon-carbon single bonds arranged in a closed ring or cyclic structure. They are a subset of alkanes, saturated hydrocarbons consisting of carbon and hydrogen atoms bonded together via single bonds. The general formula for cycloalkanes is (CnH2n), where n represents the number of carbon atoms in the ring. 1st member of cycloalkanes is Cyclo-propane (Formula: C3H6). Cycloalkanes are commonly found in nature and synthesized in the laboratory for various applications.
Nomenclature of Cycloalkanes:
1. Simple Cycloalkanes:
– The prefix “cyclo” is added to the alkane name corresponding to the number of carbon atoms in the ring for cycloalkanes with a single ring.
– The name is followed by the suffix “-ane” to indicate that the compound is an alkane.
– The number of carbon atoms in the ring determines the prefix used:
– Cyclopropane: 3 carbon atoms in the ring
– Cyclobutane: 4 carbon atoms in the ring
– Cyclopentane: 5 carbon atoms in the ring
– Cyclohexane: 6 carbon atoms in the ring
– Cycloheptane: 7 carbon atoms in the ring
– Cyclooctane: 8 carbon atoms in the ring
– Cycloalkanes with more than eight carbons are named similarly, using the appropriate prefix for the number of carbon atoms.
2. Substituted Cycloalkanes:
– If substituents are present on the cycloalkane ring, they are named using the common system.
– The substituent names are listed alphabetically before the parent cycloalkane name.
– The position of each substituent is indicated by assigning a number to each carbon atom in the ring, starting with the carbon atom that gives the lowest set of locants to the substituents.
– If multiple substituents are present, the prefixes “di-,” “tri-,” etc., indicate the number of identical substituents.
– If different substituents are present, they are listed in alphabetical order.
3. Examples:
– 1-Methylcyclohexane: Cyclohexane with a methyl substituent on carbon atom 1.
– 1,3-Dimethylcyclopentane: Cyclopentane with methyl substituents on carbon atoms 1 and 3.
– 1-Ethyl-3-methylcyclohexane: Cyclohexane with ethyl substituent on carbon atom 1 and methyl substituent on carbon atom 3.