PAGE-BY-PAGE NOTES: IUPAC Naming of Functional Groups and Derivatives

Page 1

  • Interchapter D focuses on Naming Compounds with a Functional Group That Calls for a Suffix, specifically Alcohols, Amines, Ketones, Aldehydes, Carboxylic Acids, and Carboxylic Acid Derivatives.

  • The page sets the stage for suffix-based naming conventions tied to the highest-priority functional group in a molecule.

Page 2

  • The Basic System for Naming a Variety of Functional Groups.

  • The root (parent) compound indicates:

    • the longest chain or ring of carbons, and

    • the presence of C=C and/or C≡C bonds.

  • Prefixes indicate the presence and locations of substituents.

  • The suffix indicates the presence of a functional group other than halo, nitro, ether, C=C, or CC.

  • Notation used: prefix + root + suffix.

Page 3

D.1 THE BASIC SYSTEM FOR NAMING COMPOUNDS HAVING A FUNCTIONAL GROUP THAT CALLS FOR A SUFFIX

  1. Determine the highest-priority functional group present.

  2. Establish the main chain or ring. The main chain or ring must contain the highest-priority functional group.

  3. Add the appropriate suffix:

    • Choose the suffix that corresponds to the highest-priority functional group.

    • Remove the “e” from the normal ane, ene, or yne ending before adding the suffix. (Nitriles are an exception.)

  4. Number the main chain or ring.

  5. Add the locator number for the highest-priority functional group.

  6. Add prefixes and the remaining locator numbers.

  • Emphasis: the suffix is dictated by the highest-priority functional group; the main chain must contain that group; the chain is numbered to give the lowest possible numbers to the highest-priority groups.

Page 4

Priority of Functional Groups

  • A table titled: "TABLE D-1 Common Functional Groups, Their Relative Priorities, and Corresponding Suffixes and Prefixes".

  • Key ideas inferred from the content:

    • Suffixes drop the final 'e' from the root when adding the suffix, with some exceptions (e.g., nitriles).

    • Highest-priority group takes precedence in naming and determines suffix and numbering.

  • Examples of entries (as interpreted from the page):

    • Carboxylic acid: suffix is "oic acid"; root prefix is "carboxy"; the class is a carboxylic acid.

    • Nitrile: suffix is "nitrile"; prefix used is "cyano"; the nitrile carbon is part of the functional group.

    • Acid anhydride: suffix is "oic"; suffix context is an anhydride; root likely related to the parent diacid unit.

    • Ester: named with guidance to see Section D.4a; generally involves an "alkyl" portion and an "alkanoate" portion.

    • Aldehyde: suffix is "al"; when present with other functionalities, the aldehyde is treated with priority rules.

    • Ketone: suffix is "one".

    • Acid chloride: related to the "oyl" ending with the chloro- prefix used for substituents.

    • Alcohol: suffix is "ol"; hydroxy as a prefix for substituents.

    • Amide: suffix is "amide"; prefix is "carbamoyl" for amides that are not the highest-priority group.

    • Amine: suffix is "amine"; prefix is "amino".

  • Note: R represents an alkyl group; the table indicates that higher-priority groups appear earlier in the list.

  • Practical takeaway: prioritize functional groups by order, and apply the corresponding suffix or prefix as dictated by the highest-priority group.

Page 5

D.2 NAMING ALCOHOLS AND AMINES

  • The main chain or ring is identified.

  • The “e” from the normal ane, ene, or yne root name is dropped and the suffix "ol" (for alcohol) or the corresponding suffix for amines is added to indicate the functional group.

  • A locator number is used when necessary to indicate where the group is located.

  • The highest-priority functional group is given the lowest possible number.

  • In these examples there is only one OH group (i.e., one alcohol).

  • Important rule: alcohols have suffix "-ol"; amines have suffix "-amine".

Page 6

Examples of Amines

  • The main chain or ring is identified.

  • The "e" from the normal ane, ene, or yne root name is dropped and the suffix "amine" is added.

  • A locator number is used when necessary; the highest-priority functional group gets the lowest possible number.

  • Statement: Amines are higher priority than nitro and halo groups.

  • Practical implication: in molecules containing multiple substituents, amine functionality outranks nitro and halo groups for suffix/prefix decisions.

Page 7

Examples of Substituted Alkenes and Alkynes

  • The main chain or ring is identified.

  • The “e” from the normal ene or yne root name is dropped and the suffix is added (in these cases, the suffix could be "ol" or "amine").

  • A locator number is used when necessary; the highest-priority functional group is given the lowest possible number.

  • Important hierarchy note: Amines and alcohols are higher priority than double and triple bonds (C=C, C≡C).

  • Practical implication: if both a carbonyl/OH/amine group and a C=C/C≡C are present, the OH/amine will influence suffix selection and numbering before addressing the multiple bonds.

Page 8

Molecules containing both OH and NH2 groups

  • The highest-priority functional group receives both the suffix and the lowest possible locator number.

  • Other groups are given prefixes and listed alphabetically.

  • Di-, tri-, etc., prefixes are used when needed to indicate multiple identical substituents.

  • Practical takeaway: when a molecule has both an alcohol and an amine (or multiple OH/NH2), the highest-priority group defines the suffix; the rest are prefixed (and alphabetized).

Page 9

Naming Molecules with Two or More of the Highest-Priority Functional Group

  1. Keep the final "e".

  2. Add the multiplying prefix for the highest-priority functional group (di, tri, etc.) immediately before the suffix to indicate how many of the highest-priority functional groups appear.

  3. Add locator numbers. Add one locator number for each of the highest-priority functional groups immediately before the multiplying prefix.

  • Example concept: if a molecule contains two OH groups (diol) and one double bond or other groups, you still use the di- before the suffix, and place numbers before the di- prefix.

Page 10

SOLVED PROBLEM: Write the IUPAC name for the compound shown here.

  • A visual example is presented with an amine group (NH2) on the structure.

  • The exercise illustrates applying the rules from pages 3–9 to assign the correct suffix, root, and locants.

Page 11

SOLVED PROBLEM: Think, Write the IUPAC name for the compound shown here. Think, Solve.

  • Questions guiding the naming process:

    • Are there any functional groups that require adding a suffix to the name?

    • If there are two or more different ones, which one has priority?

    • What is the longest carbon chain that contains the highest-priority functional groups?

    • How should you number the main chain so those groups are encountered the earliest?

    • Are there any C=C or C≡C bonds within that main chain?

    • Should you drop the final “e” before adding the suffix?

    • How should you account for the names, numbers, and locations of all functional groups?

  • The focus is on applying priority, chain selection, and numbering strategies to determine the IUPAC name.

Page 12

SOLVED PROBLEM: Think, Solve. The molecule contains OH and NH2 groups, both calling for a suffix.

  • OH group has higher priority than NH2, so the suffix is ol.

  • Questions guiding the naming: identify highest-priority group, determine chain that contains it, and place locants accordingly.

  • Notes emphasize choosing the longest chain containing all high-priority groups (OHs in this case).

  • The chain is numbered so the first OH is at the lowest locant (C-1 in the example).

Page 13

SOLVED PROBLEM: Solve 2. Write the IUPAC name for the compound shown here. Think, Solve.

  • Observations from the solution description:

    • There is one C=C bond in the main chain, located at C-5.

    • Because there are two OH groups, the final “e” in ene is kept before adding the suffix.

    • The prefix di- is added to indicate two OH groups, and the OH locations are given as 1 and 4.

    • A substituent amino group is present at C-3 and a (2-methylpropyl) substituent at C-2.

    • The resulting name is: 3$-amino-2-(2$-$methylpropyl)$-hex-5-ene-1,4-diol.

  • The questions emphasize considering C=C placement, multiple OH groups, and substituent locations.

Page 14

How to Name a Molecule with More Than One Alkyl Group Bonded to the Amine Nitrogen

  • Rules for N-Substituents on amines:

    1. Determine which alkyl group attached to N establishes the root.

    2. Treat the other alkyl groups attached to N as prefixes.
      Each of these alkyl groups is given an italic N locator instead of a number.

  • This approach accounts for tertiary and quaternary amines where N bears multiple substituents.

Page 15

Examples of Alkyl Groups Attached to the Amine Nitrogen
(a) The N is located at C-1 and there is a methyl group attached to it.

  • Diagrammatic depiction shows N attached to a methyl group.

  • Example name given: N-Methylcyclohex-3-en-1-amine.

(b) The N is located at C-2. There is one ethyl group attached to N, and there are two methyl groups: one attached to N and the other to C-3.

  • Example name given: N-Ethyl-5-methoxy-N,3-dimethylpentan-2-amine.

  • Key idea: N-substituent naming uses the N locator for substituents attached to nitrogen, and other substituents on carbon are named as usual.

Page 16

D.3 NAMING KETONES AND ALDEHYDES

  • Ketones and aldehydes each contain a carbonyl (C=O) group.

  • Both require a suffix when naming:

    • Ketone: suffix "one".

    • Aldehyde: suffix "al".

  • Additional points:

    • The C=O group has higher priority than OH, so OH is treated as a substituent when appropriate.

    • The main chain should be chosen to include the carbonyl group for aldehydes/ketones.

Page 17

Examples of Ketones
(a) The C=O group can be located only at C-2 in the given example, so no locator number is added.
(b) The OH group is treated as a substituent because a C=O has higher priority than an OH.
(c) The main chain is chosen to include both C=O groups in the given example.
(d) and (e) illustrate specific ketone naming with additional substituents and ring systems:

  • 4-Hydroxypentan-2-one

  • 3-Propylpentane-2,4-dione

  • Cyclohexane-1,2,4-trione

  • Takeaway: position of carbonyls and additional substituents are accounted for in the root and suffix selection.

Page 18

Naming Aldehydes; Naming Cyclic Aldehydes

  1. Establish the root as cycloalkanecarbaldehyde. The cycloalkane portion is dictated by the ring size attached to the HC=O group.

  2. Number the carbons of the ring: C-1 is the ring carbon attached to the HC=O group, and numbering increases around the ring.

  • Practical rule: for cyclic aldehydes, use cycloalkanecarbaldehyde naming with 1-position at the substituent-bearing carbon.

Page 19

D.4 NAMING CARBOXYLIC ACIDS, ACID CHLORIDES, AMIDES, AND NITRILES

  • General approach:

    • Determine the highest-priority functional group (this group gets the suffix in the name).

    • Determine the longest chain containing this group.

    • Number accordingly (lowest possible number).

    • Identify and number remaining functional groups.

    • Use prefix identifiers for remaining functional groups.

  • This page sets the framework for handling the major carboxyl-containing derivatives.

Page 20

Nitriles

  • The carbon in the nitrile functional group is always part of the functional group.

  • When the nitrile is the highest priority functional group, this carbon is counted in the chain.

  • When the nitrile is not the highest priority functional group, this carbon is not counted as part of the chain because the cyano prefix includes the carbon.

  • Practical implication: chain inclusion of the nitrile carbon depends on its priority relative to other functionalities.

Page 21

Amides

  • Amides follow the same classification trend as amines.

  • Use the N locator to identify the locations of groups attached to nitrogen.

  • Carbamoyl is the prefix used for amides that are not the highest priority functional group.

  • The amide carbon is not numbered when the amide is a substituent.

  • Key idea: when amide is the highest-priority group, the suffix is used; otherwise, prefixes like carbamoyl are used.

Page 22

SOLVED PROBLEM: Write the IUPAC name for L-asparagine, one of the naturally occurring amino acids, shown in its un-ionized form. (Stereochemistry not considered for this problem.)

  • The example demonstrates applying the rules to an amino acid containing multiple functional groups (carboxyl, amino, amide-related groups).

Page 23

SOLVED PROBLEM: Think, Write the IUPAC name for L-asparagine (un-ionized form). Think, Solve.

  • Guiding questions mirror those in Page 11: identify highest-priority group, determine suffix, classify other groups as substituents, determine longest chain, locate substituents, etc.

Page 24

SOLVED PROBLEM: Solve. Write the IUPAC name for L-asparagine (un-ionized form). Think, Solve.

  • Explanation highlights:

    • Highest-priority functional group is CO2H (carboxyl); suffix is oic acid; numbering begins at CO2H carbon.

    • Other groups present: NH2 and O=C—N, treated as substituents with prefixes amino and carbamoyl, respectively.

    • Longest carbon chain containing CO2H is three carbons, i.e., propanoic acid base.

    • Amino group attached at C-2; carbamoyl group at C-3.

    • Final name: 2−extamino−3−extcarbamoylpropanoicacid2- ext{amino}-3- ext{carbamoylpropanoic acid}

  • Questions emphasize identifying the highest-priority group, locating substituents, and determining chain length.

Page 25

Carboxylic Acid Derivatives on a Ring Structure

  1. Include both the ring and the functional group in the root name:

    • A cyclic carboxylic acid takes the form extcycloalkanecarboxylicacidext{cycloalkanecarboxylic acid}.

    • A cyclic amide takes the form extcycloalkanecarboxamideext{cycloalkanecarboxamide}.

    • A cyclic nitrile takes the form extcycloalkanecarbonitrileext{cycloalkanecarbonitrile}.

  2. Number the carbons of the ring. C-1 is the ring carbon attached to the carbonyl-containing group, and numbering increases around the ring.

  • This page extends ring systems to carboxylic derivatives.

Page 26

D.5 NAMING ESTERS AND ACID ANHYDRIDES

  • The rules for naming esters and acid anhydrides differ from those for other carboxylic acid derivatives.

  • They both are made up of two parts that have to be named.

  • It is common for these parts to be different from each other.

Page 27

Nomenclature Rules of Esters

  1. Establish the alkanoate portion as the root for the ester. The name of the alkanoate is determined by the number of carbons in the chain.

  2. Number the alkyl and alkanoate chains. C-1 of the alkanoate chain is assigned to the CO2 carbon, and C-1 of the alkyl group is assigned to the carbon that is attached to the ester oxygen.

  3. Establish the alkyl portion of the ester.

  4. Write the parent name of the ester in the format alkyl alkanoate. Notice that there is a space between the two portions of the name.

  5. Add the names and locator numbers of the substituents.

  • Practical takeaway: esters are named as alkyl (alkanoate), reflecting both halves of the ester linkage.

Page 28

Examples of Esters

  • Both the alkyl and alkanoate groups of an ester can have attached substituents.

  • Each carbon chain can have a numbering system.

  • This reinforces that ester naming can be detailed with multiple substituents on either side of the ester linkage.

Page 29

SOLVED PROBLEM: Write the IUPAC name for the molecule shown here. (The configuration of the asymmetric carbon is S.)

  • Demonstrates applying stereochemical considerations (R/S) in naming when relevant to esters and nitriles in the example (S is given).

Page 30

SOLVED PROBLEM: Think, Write the IUPAC name for the molecule shown here. (The configuration of the asymmetric carbon is S.) Think, Solve.

  • Guiding questions cover:

    • What functional groups are present?

    • Which has the highest priority?

    • What are the names of the alkyl and alkanoate portions of the ester?

    • How to account for substituents and stereochemistry in the final name?

Page 31

SOLVED PROBLEM: Solve. Write the IUPAC name for the molecule shown here. (The configuration of the asymmetric carbon is S.)

  • A nitrile, alcohol, and ester are present.

  • The ester has the highest priority.

  • The alkyl portion is cyclopentyl; the alkanoate portion is propanoate.

  • The OH and CN groups on C-3 belong to the alkanoate portion and are named with locants in front of the alkanoate portion.

  • The asymmetric carbon is specified as S at the front of the alkanoate name.

  • Final name example: ext{cyclopentyl} igl( ext{S}igr) ext{-3-cyano-3-hydroxypropanoate}

  • Key concept: in mixed-functional esters, the highest-priority group dictates suffix/major part, while other groups become prefixes, sometimes attached to the ester portion.

Page 32

Nomenclature Rules for Acid Anhydrides

  1. For a symmetric acid anhydride, name the molecule according to the general form extalkanoicanhydrideext{alkanoic anhydride}.

  2. If the acid anhydride is unsymmetric, name the molecule according to the general form extalkanoicalkanoicanhydrideext{alkanoic alkanoic anhydride}.

  • The two instances of alkanoic will be different, each corresponding to one of the two different carboxylic acids that would be required to form the anhydride via dehydration.

  • The two instances of alkanoic should appear in alphabetical order.

  • Practical rule: use two carboxy-derived fragments, ordered alphabetically, when the anhydride is unsymmetric.

Page 33

Examples of Acid Anhydrides

  • Each carbon-containing group is the same as in the corresponding carboxylic acid:

    • Propanoic anhydride corresponds to propanoic acid units.

    • Benzoic ethanoic anhydride corresponds to benzoic acid and ethanoic acid units.

  • The page demonstrates naming both symmetric and asymmetric acid anhydrides with examples like Propanoic anhydride and Benzoic ethanoic anhydride.