Cyclic Hydrocarbons theory

Organic Formulation: Cyclic Hydrocarbons

They are closed-chain hydrocarbons. Depending on whether or not they have unsaturations, they are classified as:

• Saturated monocyclic hydrocarbons (cycloalkanes).
• Unsaturated monocyclic hydrocarbons (cycloalkenes and cycloalkynes)

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Saturated monocyclic hydrocarbons.

The carbon atoms of the cyclic hydrocarbon are joined by single bonds. They are corresponding to the general formula C_nH_2n.

They are named by prefixing the name cycle to the open chain alkane name of the same number of carbon atoms.

Examples:

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1. Cyclepropane
2. Cyclebutane
3. Cyclehexane

Univalent radicals cycloalkanes.

Radicals or univalent groups derived from cycloalkanes by loss of a hydrogen atom are named as alkanes acyclic, that is to say, by replacing the termination ane by yl.

Examples:

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1. Cyclepropyl
2. Cyclebutyl
3. Cyclehexyl

Cyclealkanes radicals.

Substituted cyclealkanes (which have radicals attached to the cycle) are named as derivatives of cyclic hydrocarbons. The cycle is numbered so that the lowest locators are assigned to all the radicals.

In simple cases, they can be named as derivatives of a open chain compound.

Examples:

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1. 1-ethyl-2-methylcyclehexane
2. 1-methyl-4-(1-methylethyl)-cyclehexane
3. 4-ethyl-1,2-dimethylcyclehexane

Unsaturated monocyclic hydrocarbons.

They are cyclic hydrocarbons with one or more double bonds or one or more triple bonds between carbon atom.

The cycle is numbered so that the lowest located are asignated to unsaturations, regardless of which are double or triple bonds.

In case of equality should be chosen numbering to assign lower numbers to the double bonds.

The numbering cycle is made in the direction of clockwise or counterclockwise, in order to get the condition expressed above.

They are named by prefixing the cycle prefix and adding the termination ene or ine.

Examples:

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1. Cyclebutene
2. Cyclehexa-1,3-diene
3. Cycleocta-1,3,5-triene
4. Cyclehexa-1,3,5-triene (Benzene)
5. Cyclehexine

Univalent radicals of the cyclealkenes and cyclealkynes.

They are derived from unsaturated cyclic hydrocarbons by loss of a hydrogen atom on a carbon atom.

They are named as hydrocarbons coming replacing ene and ine terminations by enyl and ynyl, respectively.

The positions of the double and triple bonds are indicated by locators; the number 1 is assigned to the carbon atom that has lost the hydrogen atom.

Examples:

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1. Cyclepenta-2,4-dienyl
2. Cyclebut-2-ynyl
3. Cyclehexa-2,5-diynyl

You can download the App BioProfe READER to practice this theory with self-corrected exercises.