4.3 IUPAC naming and also formulae (ESCKG)

What is IUPAC naming? (ESCKH)

In order to give compounds a name, particular rules have to be adhered to. When naming organic compounds, the IUPAC (International Union of Pure and also Applied Chemistry) nomenclature (naming scheme) is supplied. This is to provide consistency to the names. It additionally allows eincredibly compound to have actually a distinct name, which is not feasible with the widespread names supplied (for instance in industry). We will first look at some of the procedures that have to be complied with once naming a compound, and also then try to apply these rules to some certain examples.

You are watching: Give the iupac name for each of the following

A great general rule to follow is to start at the end (the suffix) and work-related backwards (from right to left) in the name.


Molecules can contain both double or triple bonds and various other practical teams (e.g. an alkene and also an alcohol sensible team in one molecule - propenol). However before, all molecules explored in this book will contain just single carbon-carbon bonds when unified via other functional groups.


Number the carbons in the longest carbon chain (Important: If the molecule is not an alkane (i.e. has actually a sensible group) you must start numbering so that the sensible group is on the carbon with the lowest feasible number). Start via the carbon at the end closest to the practical group.

Look for any branched groups:

The branched teams need to be detailed before the name of the major chain in alphabetical order (ignoring di/tri/tetra).

If tbelow are no branched groups this step deserve to be ignored.


Number

prefix

2

di-

3

tri-

4

tetra-


Table 4.7: Prefixes for multiple substituents via the very same name. These use to multiple sensible groups also.


For the alkyl halides the halogen atom is treated in a lot the exact same means as branched groups:

To name them take the name of the halogen atom (e.g. iodine) and rearea the -ine via -o (e.g. iodo).

Halogen

name

fluorine

fluoro

chlorine

chloro

bromine

bromo

iodine

iodo


Table 4.8: Naming halogen atoms in organic molecules.


The halogen atoms need to be provided prior to the name of the primary chain in alphabetical order (neglect di/tri/tetra).

If tbelow are no halogen atoms this action deserve to be ignored.

Combine the elements of the name right into a solitary word in the following order:

branched groups/halogen atoms in alphabetical order (ignoring prefixes) presettle of primary chain name finishing according to the sensible group and its position on the longest carbon chain. temp text

Naming hydrocarbons (ESCKJ)

Naming alkanes

The suffix for an alkane is -ane.

Worked example 1: Naming the alkanes


Give the IUPAC name for the complying with compound:

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Note: The numbers attached to the carbon atoms would certainly not normally be shown. The carbon atoms have been numbered to help you to name the compound.


Identify the practical group

The compound is a hydrocarbon via single bonds between the carbon atoms. It is an alkane and will have actually a sufdeal with of -ane.


Find the longest carbon chain

Tright here are four carbon atoms in the longest chain. The presolve of the compound will be but-.


Number the carbon atoms in the longest chain

The numbering has been done for you below.


Look for any type of branched team, name them and also provide their position on the carbon chain

Tbelow are no branched groups in this compound.


Combine the aspects of the name into a solitary word

The name of the compound is butane.


Worked example 2: Naming the alkanes


Give the IUPAC name for the adhering to compound:

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Identify the practical group

The compound is a hydrocarbon with single bonds between the carbon atoms. It is an alkane and also will certainly have actually the suffix -ane.


Find the longest carbon chain

Tright here are 3 carbon atoms in the longest chain. The prefix for this compound is prop-.


Number the carbons in the carbon chain

If we start at the carbon on the left, we have the right to number the atoms as shown in red (left). If we begin at the carbon on the appropriate, we deserve to number the atoms as shown in blue (right).

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Look for any type of branched groups, name them and give their place on the carbon chain

Tright here is a branched group attached to the second carbon atom. In this instance the methyl group is on carbon 2 regardless of which side you number the longest chain from.

This group has actually the formula ( extCH_3), which is methane without a hydrogen atom. However, because it is not part of the main chain, it is offered the sufsolve -yl (i.e. methyl). The place of the methyl group comes just prior to its name (see the next step).


Combine the facets of the compound"s name into a single word in the order of branched group; prefix; name ending according to the practical group

The compound"s name is 2-methylpropane.


Worked instance 3: Naming the alkanes


Give the IUPAC name for the adhering to compound:

( extCH_3 extCH( extCH_3) extCH( extCH_3) extCH_3)

(Remember that the side teams are displayed in brackets after the carbon atom to which they are attached).


Draw the structural formula from its condensed structural formula

The structural formula of the compound is:

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Identify the practical group

The compound is a hydrocarbon through single bonds in between the carbon atoms. It is an alkane and will have the sufresolve -ane.


Find the longest carbon chain

There are 4 carbon atoms in the longest chain. The predeal with for this compound is but-.


Number the carbons in the carbon chain

If we start at the carbon on the left, we deserve to number the atoms as shown in red (left). If we begin at the carbon on the best, we have the right to number the atoms as presented in blue (right).

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Look for any type of branched groups, name them and also provide their place on the carbon chain

Tright here are two methyl groups attached to the main chain. The initially one is attached to the second carbon atom and also the second methyl team is attached to the third carbon atom. Notice that in this example it does not issue just how you have actually preferred to number the carbons in the main chain; the methyl groups are still attached to the second and 3rd carbon atoms and so the naming of the compound is not influenced.

This group will certainly be 2,3-dimethyl-


Combine the elements of the compound"s name right into a solitary word in the order of branched groups; prefix; name finishing according to the functional group

The compound"s name is 2,3-dimethylbutane.


Worked instance 4: Naming the alkanes


Give the IUPAC name for the complying with compound:

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Identify the useful group

The compound is a hydrocarbon through single bonds between the carbon atoms. It is an alkane and also will have the sufresolve -ane.


Find the longest carbon chain and number the carbons in the longest chain

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Tbelow are six carbons in the longest chain if they are numbered as presented in red (on the left). There are just five carbon atoms if they are numbered as presented in blue (right). Therefore, the red numbering (on the left) is correct and also the presettle for the compound is hex-.


Look for any type of branched teams, name them and also offer their place on the carbon chain

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There is one methyl team attached to the main chain. If we number as shown in red (on the left) the methyl is attached to the fourth carbon atom. If we number as displayed in blue (on the right) the methyl is attached to the third carbon atom.

After functional groups, the branched teams should have the lowest numbers possible. As such the blue numbering (on the right) is correct. The methyl is attached to the third carbon atom (3-methyl).


Combine the aspects of the compound"s name into a solitary word in the order of branched groups; prefix; name ending according to the useful group

The compound"s name is 3-methylhexane.


Worked instance 5: Naming the alkanes


Draw the semi-structural structural and condensed structural formula for the organic compound 2,2,4-trimethylhexane


Identify the practical group

The name ends in -ane therefore the compound is an alkane.


Determine the variety of carbon atoms in the longest chain

The longest chain has actually the presettle hex-. There are therefore 6 carbon atoms in the longest chain.

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Look for any type of branched groups and also place them on the structure

The compound is 2,2,4-trimethylhexane. Thus there are 3 branched teams. Two on carbon 2 and one on carbon 4.

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Combine this information and add the hydrogen atoms

Carbon atoms can have 4 single bonds. Therefore wherever a carbon atom has less than four bonds attract in hydrogen atoms till tright here are 4 bonds.

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Condense the structural formula

First condense the main chain: ( extCH_3 extCCH_2 extCHCH_2 extCH_3)

Then include the side chains (in brackets) on the pertinent carbon atoms:

( extCH_3 extC( extCH_3)_2 extCH_2 extCH( extCH_3) extCH_2 extCH_3)


Naming alkanes


Textbook Exercise 4.8

Give the structural formula for each of the following alkanes


Octane


The sufdeal with -ane tells us that this is an alkane. The presolve oct- tells us that there are eight carbon atoms in the longest chain.

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Propane


The sufresolve -ane tells us that this is an alkane. The presettle prop- tells us that there are three carbon atoms in the longest chain.

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2-methylpropane


The sufresolve -ane tells us that this is an alkane. The presettle prop- tells us that tright here are 3 carbon atoms in the longest chain. 2-methyl tells us that tright here is a methyl (( extCH_3-)) branched team attached to the second carbon atom.

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3-ethylpentane


The sufsettle -ane tells us that this is an alkane. The presettle pent- tells us that tright here are 5 carbon atoms in the longest chain. 3-ethyl tells us that tright here is an ethyl branched team (( extCH_3 extCH_2-)) team attached to the 3rd carbon atom.

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Give the IUPAC name for each of the adhering to alkanes:


( extCH_3 extCH_2 extCH( extCH_3) extCH_2 extCH_3)


This is difficult to do unless you attract the structural formula of the molecule out. It is recommfinished that you carry out this in exams.

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Tright here are 5 carbons in the longest chain so the preresolve is pent-. Tbelow are only single carbon-carbon bonds and no other useful team so the compound is an alkane and also the sufresolve is -ane. There is one methyl group at position 3 (you deserve to number from either end of the chain for this example). So the compound is 3-methylpentane.


( extCH_3 extCH( extCH_3) extCH_2 extCH( extCH_3) extCH_3)


This is tough to perform unless you draw the structural formula of the molecule out. It is recommended that you do this in exams.

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Tbelow are five carbons in the longest chain, so the predeal with is pent-. Tbelow are just single carbon-carbon bonds so the compound is an alkane and the sufsolve is -ane. Tbelow is one methyl team at position 2 and also one at position 4 (when aget you can number from either end). So the compound is

2,4-dimethylpentane.


( extCH_3 extCH_2 extCH_2 extCH_2 extCH_2 extCH_3)


This is tough to perform unless you draw the structural formula of the molecule out. It is recommended that you do this in exams.

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Tright here are 6 carbon atoms in the longest chain so the presolve is hex-. Tright here are only single carbon-carbon bonds and no various other sensible group so the compound is an alkane and also the sufsolve is -ane. Tright here are no branched teams, so the molecule is hexane.


( extCH_3 extCH_3)


This is tough to perform unless you attract the structural formula of the molecule out. It is recommended that you execute this in exams.

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There are 2 carbon atoms in the longest chain so the presolve is eth-. Tbelow are only single carbon-carbon bonds and no other useful group so the compound is an alkane and also the sufsolve is -ane. Tright here are no branched teams, so the molecule is ethane.


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Tright here are 4 carbon atoms in the longest chain, so the presettle is but-. Tbelow are two methyl branches at positions 2 and 3. The sensible group is an alkane, so the sufresolve is -ane. Combining all this information we get: 2,3-dimethylbutane. Keep in mind that in this instance it does not matter which end you start numbering from.


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Tbelow are four carbon atoms in the longest chain so the preresolve is but-. The functional team is an alkane, so the sufresolve is -ane. Tright here is one branched group which is a methyl team and also this is at place 2. The molecule is 2-methylbutane.

Keep in mind that in this instance it does matter which method you number the chain as the branched team needs to have actually the lowest number feasible and also so the compound is not 3-methylbutane.


Naming alkenes

The sufsettle for an alkene is -ene.

Worked instance 6: Naming the alkenes


Give the IUPAC name for the following compound:

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Identify the useful group

The compound has actually a dual carbon-carbon bond and is an alkene. It will have actually the sufresolve -ene.


Find the longest carbon chain containing the sensible group

The sensible team is a twin bond, so the longest chain should contain the double bond. There are 4 carbon atoms in the longest chain and so the prefix for this compound will be but-.


Number the carbon atoms

Remember that the carbon atoms should be numbered so that the sensible group is at the lowest numbered carbon atom possible. In this situation, it doesn"t issue whether we number the carbons from the left to appropriate, or from the right to left. The double bond will still loss between the second and also 3rd carbon atoms.


Look for any branched groups, name them and also offer their place on the carbon chain

Tright here are no branched teams in this molecule.


Combine the aspects of the name right into a single word in the adhering to order: branched groups; prefix; name finishing according to the useful group and also its position alengthy the longest carbon chain

The name of this compound is but-2-ene or 2-butene.


Worked instance 7: Naming the alkenes


Draw the structural and molecular formula for the organic compound

3-methylbut-1-ene


Identify the sensible group

The suffix -ene implies that this compound is an alkene and also tbelow have to be a twin bond in the molecule. The number 1 automatically prior to the sufsettle indicates that the double bond have to be at the first carbon in the chain (but-1-ene).


Determine the number of carbon atoms in the longest chain containing the practical group

The presolve for the compound is but- so tbelow must be four carbons in the longest chain containing the double bond.

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Look for any type of branched groups

There is a methyl group at the third carbon atom in the chain. Count from the left so that the double bond carbon is the first carbon atom.

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Combine this information and add the hydrogen atoms

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Reduce the structural formula to the molecular formula

There are 5 carbon atoms and also 10 hydrogen atoms so the molecular formula is ( extC_5 extH_10).

(Remember that tbelow is no structural indevelopment provided by the molecular formula)


Worked instance 8: Naming the alkenes


Give the IUPAC name for the following compound:

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Identify the useful group

The compound is an alkene and will have the sufresolve -ene. Tright here is a double bond between the first and also second carbons and also additionally in between the 3rd and also fourth carbons. The organic compound therefore includes "1,3-diene".


Find the longest carbon chain containing the useful team, and number the carbon atoms

Remember that the primary carbon chain need to contain both the double bonds. Tright here are four carbon atoms in the longest chain containing the double bonds and also so the presettle for this compound will certainly be but-. The carbon atoms are currently numbered 1 to 4 in the diagram.


Look for any kind of branched groups, name them and provide their position on the carbon chain

Tright here is an ethyl team on the second carbon.

Keep in mind that if we had actually numbered from the ideal to left the sufdeal with would still have actually been 1,3-diene, however the ethyl group would certainly have been on the 3rd carbon. So we had to number left to ideal.


Combine the elements of the name right into a solitary word in the following order: branched groups; prefix; name finishing according to the sensible team and its place alengthy the longest carbon chain

The name of this compound is 2-ethylbut-1,3-diene.


Naming alkenes


Textbook Exercise 4.9

Give the IUPAC name for each of the adhering to alkenes:


( extCH_2 extCHCH_2 extCH_2 extCH_3)


Draw the structural representation:

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The molecule contains a dual carbon-carbon bond. It is an alkene and also so the sufsettle is -ene. There are 5 carbons in the longest chain, so the prefix is pent-. Tright here are no branched teams. The double bond occurs in between carbons 1 and 2. So the molecule is 1-pentene or pent-1-ene.

Keep in mind that the means you number the carbon atoms matters below, the molecule is not pent-4-ene.


( extCH_3 extCHCHCH_3)


Draw the structural representation:

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The molecule consists of a double carbon-carbon bond. It is an alkene and so the sufsolve is -ene. Tright here are four carbons in the longest chain so the presettle is but-. There are no branched teams. The double bond occurs between carbons 2 and 3. The molecule is 2-butene or but-2-ene.


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The compound contains 2 double carbon-carbon bonds. It is an alkene and so the suffix is -diene. Tbelow are four carbons in the longest chain containing the double bonds, so the preresolve is but-. There are no branched chains. The initially double bond occurs in between carbons 1 and 2. The second double bond occurs between carbons 3 and also 4. The compound is but-1,3-diene.


Give the structural formula for each of the adhering to alkenes:


ethene


The predeal with eth- tells us there are two carbon atoms in the chain. The sufresolve -ene tells us tright here is a dual bond in between these carbon atoms.

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hex-1-ene


The presolve hex- tells us tbelow are six carbon atoms in the chain. The sufresolve -1-ene tells us tbelow is a dual bond between the first and also second carbon atoms.

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hept-3-ene


The presettle hept- tells us tbelow are salso carbon atoms in the chain. The sufsolve -3-ene tells us tright here is a double bond in between the third and fourth carbon atoms.

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4-ethyloct-3-ene


The predeal with oct- tells us there are eight carbon atoms in the longest chain containing the sensible team. The sufsolve -3-ene tells us tright here is a dual bond between the 3rd and fourth carbon atoms. 4-ethyl tells us that there is an ethyl (( extCH_3 extCH_2-)) branched group attached to the fourth carbon atom.

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Naming alkynes

The sufsolve for an alkyne is -yne.

Worked instance 9: Naming the alkynes


Give the IUPAC name for the following compound:

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Identify the functional group

Tright here is a triple bond in between 2 of the carbon atoms, so this compound is an alkyne. The sufsettle will certainly be -yne.


Find the longest carbon chain containing the sensible group

The practical team is a triple bond, so the longest chain need to contain the triple bond. Tright here are six carbon atoms in the longest chain. The preresolve of the compound"s name will be hex-.


Number the carbons in the longest chain

In this example, you will must number the carbons from appropriate to left so that the triple bond is in between carbon atoms via the lowest numbers (the suffix for the compound will certainly therefore be -2-yne).

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Look for any type of branched teams, name them and also assign the number of the carbon atom to which the group is attached

Tright here is a methyl (( extCH_3)) group attached to the fifth carbon (remember we have numbered the carbon atoms from right to left).


Combine the facets of the name right into a single word in the adhering to order: branched groups; prefix; name finishing according to the functional team and its place along the longest carbon chain

If we follow this order, the name of the compound is 5-methylhex-2-yne.


Worked example 10: Naming the alkynes


Give the IUPAC name for the following compound:

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Identify the functional group

There are two triple bonds. The sufsolve will therefore be -diyne.


Find the longest carbon chain containing the useful group

The functional group is a triple bond, so the longest chain need to contain all triple bonds. The longest carbon chain contains seven carbon atoms, therefore the presettle will certainly be hept-.


Number the carbons in the longest chain

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Numbering from left to appropriate (shown in red) the first triple bond is on carbon 1 and also the second is on carbon 5. The sufsolve will therefore be -1,5-diyne.

(Numbering from best to left (presented in blue) will certainly offer the sufdeal with -2,6-diyne, and also is incorrect).


Look for any type of branched groups

There are no branched teams for this molecule.


Combine the aspects of the name right into a solitary word in the following order: branched groups; prefix; name finishing according to the sensible team and also its place along the longest carbon chain

The name of the compound is hept-1,5-diyne.


Worked instance 11: Naming the alkynes


Draw the structural and also condensed structural formula for the organic compound

6-methylhept-3-yne


Identify the practical group

The sufsettle -3-yne implies that this compound is an alkyne and also tright here have to be a triple bond situated on carbon number 3.


Determine the variety of carbon atoms in the longest chain containing the practical group

The presolve for the compound is hept- so there must be salso carbons in the longest chain.

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Look for any kind of branched groups

There is a methyl team located on carbon number 6.

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Combine this indevelopment and include the hydrogen atoms

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Conthick the structural formula

First conthick the main chain: ( extCH_3 extCH_2 extCCCH_2 extCHCH_3)

Then add the side chains (in brackets) on the relevant carbon atoms:

( extCH_3 extCH_2 extCCCH_2 extCH( extCH_3) extCH_3)


Naming alkynes


Textbook Exercise 4.10

Give the structural formula for each of the complying with alkynes:


ethyne


The prefix eth- tells us there are two carbon atoms in the longest chain. The sufdeal with -yne tells us tbelow is a triple bond in between the carbon atoms.

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pent-1-yne


The prefix pent- tells us there are five carbon atoms in the longest chain. The sufsettle -1-yne tells us tright here is a triple bond in between the first and second carbon atoms.

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5-methylhept-3-yne


The predeal with hept- tells us there are seven carbon atoms in the longest chain. The sufresolve -3-yne tells us tbelow is a triple bond in between the 3rd and also fourth carbon atoms. 5-methyl tells us tbelow is a methyl branched chain on the fifth carbon atom.

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Give the IUPAC names for the adhering to alkynes:


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There is a triple carbon-carbon bond. This compound is an alkyne and also will have the sufresolve -yne. There are 6 carbon atoms in the longest chain, therefore the predeal with will certainly be hex-. The triple bond is in between the third and fourth carbon atoms regardmuch less of just how you number the chain (-3-yne). Tbelow are two branched methyl groups. Depending on the order of numbering they are either on the fourth carbon atom (left to right) or the second carbon atom (right to left). The reduced numbering is correct (best to left) and as tbelow are 2 methyl teams this is 2,2-dimethyl. The molecule is 2,2-dimethylhex-3-yne.


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Tbelow is a triple carbon-carbon bond. This compound is an alkyne and will have actually the suffix -yne. Tbelow are three carbon atoms in the longest chain, therefore the presolve will be prop-. The triple bond is between the first and also second carbon atoms (numbering from the left) making the sufsolve -1-yne. Tright here are no branched groups. This molecule is prop-1-yne or propyne.


( extCH_3 extCCCH_3)


Draw the structure:

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Tright here is a triple carbon-carbon bond. This compound is an alkyne and also will certainly have actually the sufsolve -yne. Tbelow are four carbon atoms in the longest chain, therefore the presettle will certainly be but-. The triple bond is in between the second and 3rd carbon atoms regardless of how you number the chain (-2-yne). There are no branched teams. This molecule is but-2-yne or 2-butyne.


Model kits are an excellent means to assist learners understand and visualise organic molecules. If you perform not have actually access to design kits yet, substitutes can be provided. A bag of jelly tots (or a comparable soft sweet) would job-related simply also, utilizing toothpicks to represent the bonds. It is also possible to make your own playdough (which can be coloured for different atoms using food colourants). A recipe is given here:

2 cups flour, 2 cups heat water, 1 cup salt, 2 tablespoons vegetable oil, 1 tablespoon of cream of tartar (this enhances elasticity, and is optional).

Mix all the ingredients together over a low warm and also stir continually.

When the dough pulls ameans from the sides of the pot, remove it from the warmth and also permit to cool.

If your dough is still sticky simply prepare it a bit much longer.

Once cool, knead the dough till it becomes smooth, then sepaprice and also include food colourant, various colours for various types of atoms.

The dough is prepared. Remember to keep it in an airtight container between supplies. If it dries out a little bit, knead in a little bit of water.

The complete procedure is gave on www.instructables.com. This playdough have the right to be supplied for all the design building tasks.

Be cautious to keep the playdough ameans from animals, as it is edible, but includes huge quantities of salt.

Building hydrocarbons

An example of ethane, ethene and also ethyne constructed with atomic version kits is given in the image below:

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Using atomic version kits, construct the molecules of methane, propane, butane, pentane and octane. If you do not have actually atomic model kits, jelly tots (or playdough) and also toothpicks will job-related just as well. Use one colour jelly tot for the carbon atoms and one for the hydrogen atoms.

Remember that carbon atoms must have actually four bonds and hydrogen atoms have the right to have only one. You must watch that all these compounds have actually a similar formula, remember they all have the basic formula ( extC_ extn extH_2 extn+2). What is the name of the homologous series that all these molecules belengthy to?

Build the molecules of prop-1-ene, but-1-ene, pent-1-ene and oct-1-ene. Use two toothpicks to recurrent a double bond. You need to check out that all these compounds have actually a comparable formula. Remember, they all have actually the general formula ( extC_ extn extH_2 extn).

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Try placing the double bond at various positions within the molecule. Does this make any distinction to the full variety of carbon and also hydrogen atoms in the molecule? What is the name of the homologous series that all these molecules belengthy to?

Build the molecules of prop-1-yne, but-1-yne, pent-1-yne and also oct-1-yne. Use 3 toothpicks to represent a triple bond. You have to see that all these compounds have a comparable formula. Remember, they are all alkynes.

Try placing the triple bond at different positions within the molecule. Does this make any type of difference to the total variety of carbon and hydrogen atoms in the molecule? What is the general formula for the alkynes?

Naming hydrocarbons