Functional Groups and IUPAC Flashcards

1
Q

What are the 3 primary rules of naming an organic compound according to the IUPAC nomenclature scheme?

A
  1. Identify the molecule’s principal functional group and find the longest carbon chain containing that functional group.
  2. Number the carbon chain from one end such that the principal functional group receives the lowest possible number.
  3. Name all other functional groups according to this numbering scheme.
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2
Q

What is the prefix for carbon chains consisting of:

  • 1 carbon?
  • 2 carbons?
A
  • 1 carbon = “meth-“
  • 2 carbons = “eth-“
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3
Q

What is the prefix for carbon chains consisting of:

  • 3 carbons?
  • 4 carbons?
A
  • 3 carbons = “prop-“
  • 4 carbons = “but-“
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4
Q

What is the prefix for carbon chains consisting of:

  • 5 carbons?
  • 6 carbons?
A
  • 5 carbons = “pent-“
  • 6 carbons = “hex-“
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5
Q

What is the prefix for carbon chains consisting of:

  • 7 carbon?
  • 8 carbons?
A
  • 7 carbon = “hept-“
  • 8 carbons = “oct-“
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6
Q

What is an alkane?

A

An alkane is an organic molecule consisting of nothing but carbon and hydrogen atoms, connected with only single bonds.

All alkanes are named with an -ane suffix, with the prefix determined by the number of carbons in the chain. The three carbon chain below is called propane.

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7
Q

What is the name of this molecule?

A

This molecule is named pentane.

To name an alkane, identify the prefix based on the number of carbons in the chain containing the largest functional group, then attach the -ane suffix.

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8
Q

What is the name of this molecule?

A

This molecule is iso-butane, or 2-methyl-propane.

Historically, alkane chains which are branched at the very end have been named with the iso- prefix. While this may show up in passages, it is very rarely tested on the MCAT, since IUPAC has moved away from that old naming convention into the new system.

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9
Q

What is an alkene?

A

An alkene is an organic molecule consisting of nothing but carbon and hydrogen atoms, containing at least one carbon-carbon double bond.

All alkenes are named with an -ene suffix, with the prefix determined by the number of carbons in the chain. The molecule below is propene.

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10
Q

What is the name of this molecule?

A

This molecule is named 2-butene.

To name an alkene, identify the prefix based on the number of carbons in the chain containing the largest functional group, then attaching the -ene suffix, along with the number of the lowest-numbered carbon participating in the double bond.

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11
Q

What is an alkyne?

A

An alkyne is an organic molecule consisting of nothing but carbon and hydrogen atoms, containing at least one carbon-carbon triple bond.

All alkynes are named with an -yne suffix, with the prefix determined by the number of carbons in the chain. The molecule below is propyne.

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12
Q

What is the name of this molecule?

A

This molecule is named 1-butyne.

To name an alkyne, identify the prefix based on the number of carbons in the chain containing the largest functional group, then attaching the -yne suffix, along with the number of the lowest-numbered carbon participating in the triple bond.

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13
Q

What is the principal functional group in this molecule?

A

The amine -NH2 is the principal functional group.

In this molecule, 1-propanamine, -NH2 is the only functional group attached to the main carbon chain.

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14
Q

What is the principal functional group in this molecule?

A

The -OH group is the principal functional group.

In general, oxygen-containing groups take priority in nomenclature, and the more bonds to oxygen in the functional group, the higher its priority. This molecule, 1-amino-2-propanol, has the -ol ending to indicate highest priority even though the amino group is on the 1 carbon.

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15
Q

At what position does the highest-priority functional group reside in this molecule?

A

The -OH is on the 1 carbon position.

By definition, the chain is numbered to give the highest priority functional group the lowest possible number. Hence any time a group is at the end of the chain, it is in the 1 position by default. This would always be called 1-butanol, never 4-butanol.

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16
Q

At what position does the highest-priority functional group reside in this molecule?

A

The highest priority group is on the 2 carbon position.

Remember: oxygen-containing functional groups take priority over nitrogen-containing groups. The chain is numbered so that the -OH group resides at the lowest possible numerical position, making this a 4-amino-2-butanol molecule.

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17
Q

At what position does the Cl group reside in this molecule?

A

The Cl is on the 3 carbon position in this molecule.

By definition, the chain is numbered so that the highest-priority functional group gets the lowest possible number. In this molecule, 3-chloro-1-butanol, the -OH must be position 1 by default.

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18
Q

At what position does the Cl group reside in this molecule?

A

The Cl group is on the 3 carbon position.

When it comes to cyclic carbon chains, still number so that the highest priority group gets the lowest possible number, by default this is 1. Then, label in whichever direction results in the lowest possible number for the remaining functional groups. This molecule is 3-chlorocyclohexanol and would never be called 5-chlorocyclohexanol.

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19
Q

What is an alcohol?

A

An alcohol is an organic molecule which has an -OH as the highest-priority functional group.

All alcohols are named with an -ol suffix, with the prefix determined by the number of carbons in the chain. The molecule below is propanol.

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20
Q

What is the name of this molecule?

A

This molecule is named 2-butanol.

To name an alcohol, identify the prefix based on the number of carbons in the chain containing the -OH functional group, then attaching the -ol suffix, along with the number that makes the -OH on as low a carbon as possible. This would never be called 3-butanol.

21
Q

What is the name of this molecule?

A

This molecule is named phenol, or benzenol.

While the second name follows the IUPAC system more closely, phenol is the name that the MCAT will use. This follows from there being a phenyl group (-C6H5) attached to the -OH group.

22
Q

What is an aldehyde?

A

An aldehyde is an organic molecule consisting of an alkane chain with a carbon-oxygen double bond on one terminal carbon of the chain.

All aldehydes are named by removing the -e from the end of the name of the parent alkane and replacing it with -al. The three carbon chain below is called propanal.

23
Q

What is the name of this molecule?

A

This molecule is named pentanal.

To name an aldehyde, remove the -e from the end of the name of the parent alkane and replace it with -al. Since an aldehyde is a terminal group (always position 1) it’s unnecessary to write 1-pentanal.

24
Q

What is a ketone?

A

An ketone is an organic molecule consisting of an alkane chain with a carbon-oxygen double bond on one of the internal carbons of the chain.

All ketones are named by removing the -e from the end of the name of the parent alkane and replacing it with -one. The three carbon chain below is called propanone, also known commonly as acetone.

25
Q

What is the name of this molecule?

A

This molecule is named 2-pentanone.

To name an ketone, remove the -e from the end of the name of the parent alkane and replace it with -one. This will always be called 2-pentanone and never 4-pentanone.

26
Q

What is a carboxylic acid?

A

An carboxylic acid is an organic molecule consisting of an alkane chain with a carbon-oxygen double bond and a hydroxyl (-OH) on one of the terminal carbons of the chain.

All carboxylic acids are named by removing the -e from the end of the name of the parent alkane and replacing it with -oic acid. The three carbon chain below is called propanoic acid.

27
Q

What is the name of this molecule?

A

This molecule is named butanoic acid.

To name a carboxylic acid, remove the -e from the end of the name of the parent alkane and replace it with -oic acid.

28
Q

What is a dicarboxylic acid?

A

A dicarboxylic acid is a molecule with two carboxylic acid functional groups.

If the molecule is a chain (rather than a ring), the acids will be at both ends of the chain. The molecule below is propanedioic acid.

29
Q

What is an acid chloride?

A

An acid chloride is a carboxylic acid derivative, where the -OH has been replaced by a -Cl.

All acid chlorides are named by removing the -oic acid from the end of the name of the parent carboxylic acid and replacing it with -oyl chloride. The three carbon chain below is called propanoyl chloride.

30
Q

What is the name of this molecule?

A

This molecule is named pentanoyl chloride.

To name an acid chloride, remove the -oic acid from the end of the name of the parent carboxylic acid and replace it with -oyl chloride.

31
Q

What is an acid anhydride?

A

An acid anhydride is the result of dehydration (loss of H2O) of two carboxylic acid molecules while joining together.

Acid anhydrides are named by adding ‘-oyl’ to the name of the first acid group, and ‘-oate’ to the other. The molecule below is called propanoyl propanoate, also known commonly as propanoic anhydride since both acids are the same.

32
Q

What is the name of this molecule?

A

This molecule is named pentanoyl pentanoate, also commonly as pentanoic anhydride.

To name an acid anhydride, add ‘-oyl’ to the name of the first acid group, and ‘-oate’ to the other. When both groups are from the same base acid, it’s common to see the name as the carboxylic acid then attach ‘anhydride’.

33
Q

What is an amide?

A

An amide is a carboxylic acid derivative, where the -OH has been replaced by an -NH2.

All amides are named by removing the -oic acid from the end of the name of the parent carboxylic acid and replacing it with -amide. The three carbon chain below is called propanamide.

34
Q

What is the name of this molecule?

A

This molecule is named hexanamide.

To name an amide, remove the -oic acid from the end of the name of the parent carboxylic acid and replace it with -amide.

35
Q

What is an ester?

A

An ester is a carboxylic acid derivative, where the -OH has been replaced by an -OR, where R is a hydrocarbon chain.

Esters are named by adding the ‘-yl’ suffix to the alkane chain which is not on the carbonyl side of the single-bonded oxygen, and the ‘-oate’ suffix to the original carboxylic acid (carbonyl side of the single-bonded oxygen). The molecule below is propyl ethanoate.

36
Q

What is the name of this molecule?

A

This molecule is named ethyl pentanoate.

Esters are named by adding the -yl suffix to the alkane chain which is not on the carbonyl side of the single-bonded oxygen, and the -oate suffix to original carboxylic acid (carbonyl side of the single-bonded oxygen).

37
Q

What is a β-keto carboxylic acid?

A

A β-keto carboxylic acid is a carboxylic acid molecule with a ketone (carbonyl) exactly two carbon atoms away from the carboxylic acid carbon.

The molecule below is β-keto butanoic acid.

38
Q

What reaction are β-keto carboxylic acids best known for?

A

β-keto carboxylic acids commonly undergo decarboxyation reactions, where the molecule loses a CO2, and is left as an enol, which rapidly tautomerizes to a ketone.

(image showing decarboxylation followed by tautomerization here)

39
Q

What is an amine?

A

An amine is an organic chemistry molecule, consisting of an alkane chain where one of the H atoms has been replaced with an NH2 functional group.

Amines are named by removing the -e suffix from the parent alkane molecule, and adding -amine. The 3-carbon molecule below is propanamine.

40
Q

What is the name of this molecule?

A

This molecule is named propanamine.

Amines are named by removing the -e suffix from the parent alkane molecule, and adding -amine.

41
Q

What is the name of this functional group?

(I’m thinking a phenyl group bound to a generic R here, for simplicity.)

A

This is the phenyl functional group.

A phenyl functional group is a benzene ring (C6H5) bound directly to the carbon chain.

42
Q

What is the name of this functional group?

(I’m thinking a benzyl group bound to a generic R here, for simplicity.)

A

This is the benzyl functional group.

A benzyl functional group is a benzene ring (C6H5) bound to the carbon chain through an intermediate CH2.

43
Q

What is the name of this functional group?

(I’m thinking a nitro group bound to a generic R here, for simplicity.)

A

This is the **nitro **functional group.

44
Q

What is a thiol?

A

A thiol is an organic molecule, chemically similar to an alcohol, with the -OH functional group replaced by an -SH.

Since sulfur is in the same group as oxygen, they have similar chemical properties. In general, in organic chemistry. the prefix thio- indicates sulfur-containing.

45
Q

What is an ether?

A

An ether is an organic molecule with two alkane chains, both single-bonded to a single oxygen atom.

Ethers are named by according to the alkane chains bonded to the oxygen. The molecule below is diethyl ether.

46
Q

What is an acetal?

A

An acetal is an aldehyde derivative, where the carbonyl has been replaced by two OR groups, where the R groups can be identical or different.

Acetals are formed via the reaction of an aldehyde molecule with two equivalents of alcohol.

47
Q

What is a ketal?

A

An ketal is a ketone derivative, where the carbonyl has been replaced by two OR groups, where the R groups can be identical or different.

Ketals are formed via the reaction of a ketone molecule with two equivalents of alcohol.

48
Q

What is the name of this functional group?

A

This functional group is an imine functional group.

Imine nomenclature is rarely tested on the MCAT; it is sufficient to know the identity of the functional group.

49
Q

What is the name of this functional group?

A

This functional group is a nitrile functional group.

Nitrile nomenclature is rarely tested on the MCAT; it is sufficient to know the identity of the functional group.