1. Nomenclature 1 Lecture PowerPoint
Introduction:
The Basic System for Naming Simple Organic Compounds

2. The Need for Systematic Nomenclature
Learning how to name specific substances is learning nomenclature.
There are millions of organic compounds, so that requires a great deal of naming in order to distinguish one compound from another.
International Union of Pure and Applied Chemistry (IUPAC) was founded about 1920 to provide a standard for naming inorganic and organic compounds.

3. IUPAC Nomenclature
We can construct a structure of this compound based upon its name.

4. Alkanes and Cycloalkanes Nomenclature
Alkanes tend to be the simplest molecules to name under the IUPAC system.
The most basic alkanes are the straight-chain alkanes, or linear alkanes.

5. Alkanes and Cycloalkanes Nomenclature continued…

6. Cycloalkanes
When the two ends of an alkane chain are bonded together to form a ring.

7. Cycloalkanes continued…

8. Alkyl Substituents, Substituted Alkanes, and Substituted Cycloalkanes
If a hydrogen atom of an alkane is replaced by another atom or group of atoms, then that alkane is substituted.
The atom or group of atoms that replaces the hydrogen is called a substituent.

9. Alkyl Substituents
Among the most common substituents are alkyl substituents. They structurally resemble alkanes and cycloalkanes, so their names are similar.
Alkyl substituents are constructed by removing a single hydrogen atom from an alkane or cycloalkane, leaving the open valence available to attach the substituent.

10. Alkyl Substituents continued…
A CH3– group is called a methyl group, because it is constructed from methane (CH4) by removing a single H.
Similarly, CH3CH2– is called an ethyl group and CH3CH2CH2– is called a propyl group.

11. Naming Substituted Alkanes
To name an alkane that contains a single alkyl substituent, we must distinguish the substituent from the main chain.

12. Naming Methylbutane and Ethylhexane
In methylbutane, the longest continuous chain contains four C atoms (so the root is butane) and a CH3 group (a methyl group) appears as a substituent on the chain.
In ethylhexane, the longest continuous chain contains six carbons (so the root is hexane) and the ethyl group is the substituent.

13. Naming Substituted Cycloalkanes
The rules for naming a substituted cycloalkane are similar to those for naming a substituted alkane.

14. Substituted Cycloalkane Examples
In methylcyclobutane, the ring contains four C atoms (so its root becomes cyclobutane) and the substituent is a CH3 group (so the prefix is methyl).
Similarly, in ethylcyclopentane, the ring contains five C atoms and the substituent is an ethyl group.

15. More on Cycloalkane Nomenclature
In ethylcyclopentane, the five-membered ring could be a cyclopentyl substituent, making the two-carbon piece the main chain (i.e., the root) of the molecule.
The name, therefore, would be cyclopentylethane instead of ethylcyclopentane.
The correct name, however, is ethylcyclopentane.

16. Rings and Chains with the Same Number of Carbons
If a molecule consists of a ring and a chain containing the same number of carbons, the root is derived from the ring, and the chain is designated the substituent.

17. Cyclopropylcyclopentane Example
This compound is called cyclopropylcyclopentane instead of cyclopentylcyclopropane, because the cyclopropyl group has fewer C atoms (three) than the cyclopentyl group (five).
Cyclopentane is the root and cyclopropyl is the substituent.

18. Naming Alkanes and Cycloalkanes with Multiple Alkyl Substituents
To indicate the number of substituents in a molecule, a prefix (di, tri, tetra, etc.) in the name must be used, which corresponds to the appropriate number.

19. Multiple Alkyl Substituents continued…

20. Multiple Alkyl Substituents continued…

21. Isomers and Numbering Systems
Changing the location of the substituent can result in a different molecule, even though it may not change the molecule’s root.
For example, there are two different molecules that could be named methylpentane.
The two methylpentane molecules are isomers because they have the same formula, but the atoms are connected together differently.

22. Isomer Naming Rules Each substituent is assigned a locator number.
The first isomer is named 3-methylpentane, because the methyl substituent appears on C3, whereas the second isomer is named 2-methylpentane, because the methyl group is attached to C2.

23. Multiple Substituents
When more than one substituent is present, as in the following examples, each is given its own locator number.
If a substituent’s locator appears in the middle of a name, then a hyphen is placed on both sides of the number.
The substituents must be listed in alphabetical order.

24. Multiple Substituents continued…
An additional rule for incorporating substituent locators is necessary if a molecule contains more than one of a particular type of substituent.

25. Examples of Multiple Substituents of the Same Kind
The “1,4” in “1,4-dicyclopropylbutane” indicates that two cyclopropyl groups are bonded to C1 and C4.
Similarly, the “2,3,3” in “4-ethyl-2,3,3-triethylhexane” indicates that there are three methyl groups, one of which is attached to C2 and two of which are attached to C3.

26. Devising the Correct Numbering System
There is usually more than one way to devise the numbering system, but the IUPAC system allows for only one.

27. Devising the Correct Numbering System continued…

28. Trivial Names and Common Alkyl Substituents
As the language of chemistry grew, a large number of common names or trivial names came into regular use, and eventually many of them became integrated into the IUPAC system.
Many are so frequently employed by a substantial number of professionals that you will need to know them to communicate effectively.
In this book, these names usually appear in parentheses, whereas IUPAC names will not.

29. Trivial Names continued…

30. Trivial Names of Common Alkyl Substituents
To learn the trivial names for the above alkyl substituents, try to recognize some specific structural features of the groups.
First, notice that all of the alkyl substituents that begin with “iso,” which can be called isoalkyl groups, possess a C atom bonded to two CH3 groups.

31. Trivial Names of Common Alkyl Substituents continued…

32. Trivial Names of Common Alkyl Substituents continued…
Secondly, the prefixes “sec-” and “tert-” stand for “secondary” and “tertiary,” respectively, and reflect the type of carbon atom at the point of attachment.
A 2° carbon is bonded to two alkyl substituents and a 3° carbon is bonded to three alkyl substituents.

33. Substituents other than Alkyl Groups
If functional groups are present, the rules previously learned can be modified and/or added to properly reflect the presence of those groups.

34. Numbering Systems for Functional Groups
The numbering systems for the main chains or rings of these compounds are no different from those used with alkanes or cycloalkanes containing alkyl substituents.

35. Ether Nomenclature
The same IUPAC rules apply to naming ethers (R-OR’), with additional considerations required to identify and name substituents.
Additional rules are needed because an O atom separates two alkyl groups, R and R’.
The root is derived from the alkyl group (R) that has the longer chain of carbon atoms.
The other alkyl group, R’, is part of the substituent OR’, and is called an alkoxy group.

36. Alkoxy Naming
The -OCH3 is a methoxy group and -OCH2CH3 is an ethoxy group.

37. Trivial Names of Haloalkanes and Ethers
Prior to the advent of the IUPAC system, compounds in each of these classes were named under a different system.
The system for haloalkanes mirrored the one for naming ionic compounds like NaCl (sodium chloride).

38. Examples of IUPAC and Trivial Names for Some Haloalkanes

39. Examples of IUPAC and Trivial Names for Some Ethers

40. Summary and Conclusions
Basic alkanes are the straight-chain alkanes, or linear alkanes.
A cycloalkane is named by placing the prefix “cyclo” in front of the name that corresponds to the straight-chain alkane having same number of carbons.
If a hydrogen atom of an alkane is replaced by another atom or group of atoms, we say that the alkane is substituted.
In an alkane possessing an alkyl substituent, the main chain is the longest continuous chain of carbon atoms.

41. Summary and Conclusions continued…
A cycloalkane with an alkyl substituent is assigned a root, which is simply the name of the corresponding unsubstituted cycloalkane.
Numbers are used to locate substituents along the main chain or ring.
For molecules with two or more different kinds of substituents, each substituent (with its corresponding prefix di-, tri-, etc.) must appear in the name.
There are many accepted trivial names.
A haloalkane requires the prefix “fluoro,” “chloro,” “bromo,” or “iodo” to indicate the presence of F, Cl, Br, or I, respectively.

42. Summary and Conclusions continued…
A nitroalkane requires the prefix “nitro” to indicate the presence of an NO2 group.
An ether requires a prefix of the form “alkoxy” to indicate the presence of the OR’ substituent.
In the trivial name of an alkyl halide, the name of the alkyl group (R) is followed by the name of the halide anion (F- = fluoride, Cl- = chloride, Br- = bromide, I- = iodide).

43. Nomenclature 2 Lecture PowerPoint
Naming Alkenes, Alkynes, and Benzene Derivatives

44. Alkenes and Alkynes
For example, CH3CH2CH3 is propane, so CH2=CHCH3 is propene and HCΞCCH3 is propyne.

45. The Numbering System for Simple Alkenes and Alkynes
If a carbon backbone is long enough, then a double or triple bond can appear at different locations, yielding constitutional isomers.
Pentene, describes both CH2=CH-CH2CH2CH3 and CH3CH=CH-CH2CH3.
In the first molecule, the double bond involves a terminal carbon, whereas in the second molecule it is internal.

46. Distinguishing Between Alkene and Alkyne Isomers
Nomenclature must be able to distinguish one molecule from all others.
A numbering system is used to establish the location of the double or triple bond in compounds.

47. Alkene and Alkyne Nomenclature
Pent-1-ene has its double bond is between C1 and C2. Pent-2-ene has its double bond between C2 and C3.

48. Substituents in Alkenes and Alkynes
Once the numbering system is established, substituents are appended to the name.

49. More on Alkene and Alkyne Nomenclature
If the carbon backbone of an alkene or alkyne is branched, then the longest continuous chain of carbons might not include the double or triple bond.

50. More on Alkene and Alkyne Nomenclature continued…
In 2-ethylhex-1-ene, the longest continuous chain contains seven C atoms, but the longest continuous chain that contains the C=C bond consists of six C atoms, so the compound is a hexene.
3-Propylhex-1-yne’s longest carbon chain that contains the triple bond has six carbons.

51. The Methylene Substituent
For some alkenes, it is difficult or impossible to name the molecule in a way that has the double bond as part of the main chain or ring
In the cases above, that substituent is H2C= , called the methylene substituent.

52. Multiple Double Bonds or Triple Bonds
For compounds having more than one double or triple bond, the name must indicate how many double bonds or triple bonds are present.

53. Multiple Double Bonds or Triple Bonds continued…
Number locators are used when different isomers are possible, depending on the positions of the double or triple bonds .

54. Trivial Names of Alkenes and Alkynes
Alkenes and alkynes have trivial names that are firmly entrenched in nomenclature.
Some of the most common ones are as follows and should be committed to memory.

55. Trivial Names of Alkenes and Alkynes continued…
Trivial names are also commonly used for substituents containing double or triple bonds.
Examples of using these common names include:

56. Benzene and Benzene Derivatives
The Lewis structure of benzene (C6H6) consists of three C=C double bonds that alternate with three C-C single bonds in a six-membered ring.
To name benzene “cyclohexa-1,3,5-triene” would actually be considered inaccurate since it behaves significantly different than an alkene. Instead it is aromatic.

57. Benzene and Benzene Derivatives continued…

58. The Numbering System for the Benzene Ring
A number is not included in the name of monosubstituted benzenes to indicate the position of the substituent because all six carbon atoms of benzene are equivalent.

59. Some Examples of Multiple Substituents on the Benzene Ring

60. The Ortho, Meta, and Para Position
For benzene rings that have two substituents, (i.e., disubstituted benzenes) the relative positions of the substituents can be designated using the non-numerical prefixes “ortho,” “meta,” or “para.”

61. The Ortho, Meta, and Para Position Examples

62. Trivial Names Involving the Benzene Ring
Because of the rich history of aromatic compounds in chemistry, several trivial names are in widespread use.
The following examples should be committed to memory.

63. Toluene and Anisole
Toluene (C6H5-CH3) and anisole (C6H5-OCH3) are monosubstituted benzenes that are acceptable root names in the IUPAC system.

64. Dimethyl Benzenes
Some trivial names describe two substituents on benzene, not just one.
The most common of these is xylene, the trivial name for dimethylbenzene, which has ortho, meta, and para isomers.

65. Substituents Containing the Benzene Ring
If a substituent on a benzene ring is sufficiently complicated, the molecule is probably easier to name if we treat the benzene ring as a substituent instead.

66. Some Examples of Phenyl Substituted Compounds

67. The Phenylmethyl (Benzyl) Group
A closely related substituent is C6H5CH2–, which is called the phenylmethyl group or the benzyl group. It can be abbreviated as PhCH2– or Bn–.

68. Summary and Conclusions
To name alkenes, cycloalkenes, and alkynes, the root is modified by replacing “ane” in the name for the analogous alkane or cycloalkane with “ene,” as well as the “yne” ending for the alkynes.
In naming the molecule, the lower of the two numbers designating the carbons of the multiple bond is placed immediately before the root.
The root name of an alkene or alkyne is derived from the longest continuous chain of carbon atoms containing the double or triple bond.

69. Summary and Conclusions continued…
Prefixes (di, tri, etc.) specify how many double and/or triple bonds are present when there is more than one.
When a benzene ring has two or more substituents, a numbering system is used to identify their locations on the ring.
The ring is numbered to give the substituents the lowest possible set of numbers.
ortho = o = 1,2-positioning; meta = m = 1,3-positioning; para = p = 1,4-positioning.

70. Nomenclature 3 Lecture PowerPoint
Considerations of Stereochemistry

71. Priority of Substituents and Stereochemical Configurations at Tetrahedral Centers: R/S Designations
The IUPAC rules for assigning the configuration at a particular stereocenter involve three basic steps:

72. R/S Designations continued…

73. Substituents Involving Only Single Bonds

74. Substituents Involving Only Single Bonds continued…

75. Example of R/S Designation
CH3, H, Cl, and Br need to have their priorities assigned.
Identify the atoms at the points of attachment as C, H, Cl, and Br.
The atomic numbers of these atoms decrease in the order: Br > Cl > C > H. Therefore, the substituent priorities are assigned to reflect this decrease.

76. Example of R/S Designation
Having established the priorities of all four substituents, we next orient the molecule so that the lowest-priority substituent (in this case, H) is pointed away.

77. A Helpful Tip
If the 4th-priority group is pointing toward you, you can determine the arrangement of the 1st, 2nd, and 3rd-priority groups (clockwise or counterclockwise), and then reverse the arrangement before assigning the R/S designation.

78. Naming Molecules with One Stereocenter
For relatively simple molecules, that often means that the (R)/(S) designation appears first in the name.

79. 2-Chlorobutane Example
For this stereoisomer of 2-chlorobutane, the substituents bonded to the stereocenter are CH3, CH2CH3, Cl, and H
We can immediately assign Cl as the first-priority substituent and H as the fourth-priority substituent but the priorities of CH3 and CH2CH3 substituents remain tied.

80. 2-Chlorobutane Example continued…
To break the tie, we proceed to Rule 2, which has us examine the set of atoms one bond away from the point of attachment.
For the CH2CH3 substituent, that set of atoms is {C,H,H} and for the CH3 group it is {H,H,H}

81. Substituents with Double or Triple Bonds
To apply these rules, it is helpful to consider adding imaginary atoms when replacing double and triple bonds with single bonds.

82. Applying the Rules for Double and Triple Bonds

83. Applying the Rules for Double and Triple Bonds continued…

84. Determining the Configuration of the Stereocenter of 3-Methylhex-1-ene
The C=C double bond has been replaced by a single bond, and single bonds to two imaginary C atoms have been added.
CH=CH2 is first priority, CH2CH2CH3 is second priority, and CH3 is third priority.

85. Determining the Configuration of the Stereocenter of 3-Methylhex-1-ene continued…
These substituents are arranged counterclockwise, the configuration is assigned S and the complete name of the molecule is (S)-3-methylhex-1-ene.

86. Molecules with More Than One Stereocenter

87. Molecules with More Than One Stereocenter continued…
The molecule can be named (R)-3-bromo-(S)-2-chloropentane.

88. Stereocenters Incorporated into Rings
When a stereocenter is part of a ring, the protocol for assigning R and S configurations does not change.
The Cl substituent has the highest priority and H has the lowest priority, however the two substituents involved in the ring are tied at the points of attachment.

89. Stereocenters Incorporated into Rings continued…
Both atoms at the point of attachment are bonded to a {C, C, C} set of atoms (i.e., another tie).
The tie is broken, however, when we reach the atoms that are two bonds away from the point of attachment.

90. Stereocenters Incorporated into Rings continued…
The set of atoms is {C, H, H} for the substituent that makes up the top half of the ring and {Br, Br, C} for the substituent that makes up the bottom half of the ring, so the latter substituent has the higher priority.

91. The cis/trans Convention for Rings

92. The cis/trans Convention for Rings continued…
These isomers cannot be specified unambiguously using the cis/trans convention.

93. Fischer Projections and the R/S Designations
Vertical bonds in a Fischer projection point away from you and horizontal bonds point toward you.
Thus, if the lowest-priority group is on a vertical bond, then the projection represents a properly oriented model.

94. Fischer Projections and the R/S Designations continued…
If the lowest-priority substituent is on a horizontal bond, instead, then we can simply reverse the order in which the first-, second-, and third-priority substituents are arranged.

95. Using the R/S Designations to Identify Enantiomers and Diastereomers
The R/S designation in the names of molecules can be used to determine the specific relationship between a pair of configurational isomers; that is, whether they are enantiomers or diastereomers of each other.

96. Example Using the R/S Designations to Identify Enantiomers
(2R,3S,4S)-2,3,4-trichlorohexane and (2S,3R,4R)-2,3,4-trichlorohexane are enantiomers of each other.
Each of the stereocenters in one is the reverse of the corresponding stereocenters in the other.

97. Example Using the R/S Designations to Identify Diastereomers
The configuration is the same at C2 in both molecules (i.e., R), but opposite at C3 and C4, so they are diastereomers.

98. Stereochemical Configurations of Alkenes: Z/E Designations
There are limitations to cis and trans alkene designations.

99. Stereochemical Configurations of Alkenes: Z/E Designations continued…
When there is more than one nonhydrogen substituent bonded to one or both alkene carbons, you cannot use cis or trans designations.

100. The Z/E System for Double Bond Configurations
Determine the configuration about a double bond by first determining which of the two substituents on each alkene carbon has the higher priority.
Afterwards, the configuration can be designated as either Z or E, depending upon the orientation of the two higher-priority substituents with respect to the double bond.

101. The Z/E System for Double Bond Configurations continued…

102. Z/E Example C2 and C3 are the atoms connected by the double bond.
CH3 beats H because its atom at the point of attachment, C, has the higher atomic number. On C3, the CH2CH3 substituent beats H.

103. Z/E Example continued…
The left isomer has the two higher-priority substituents on the same side of the double bond, so the configuration is Z.
The right-sided isomer has the two higher-priority substituents are on opposite sides of the double bond, so the configuration is E.

104. Assigning Configurations to Molecules with More Than One Alkene Group
When a molecule has two or more alkene groups that can be assigned either an E or a Z configuration, the name of the molecule must do so unambiguously.

105. Multiple Z/E Designations
In the penta-1,3-diene isomer on the left below, there are two double bonds but only one E/Z configuration is assigned.
The double bond at C1 cannot have an E/Z con- figuration, because two H atoms are bonded to C1.

106. Summary and Conclusions
Stereochemical configurations for tetrahedral stereocenters can be assigned using R/S designations.
Stereochemical configurations for double bonds can be assigned using E/Z designations.
Both types of assignments require establishing priorities to substituents using the Cahn-Ingold-Prelog rules.
According to the Cahn-Ingold-Prelog rules, the substituent with the higher atomic number at the point of attachment has the higher priority.
To break the tie between substituents attached by the same atom, the sets of atoms one bond farther away from the point of attachment are examined.

107. Summary and Conclusions continued…
When a tetrahedral stereocenter is part of a ring, the protocol for assigning R and S configurations does not change.
In Fischer projections, the R/S designation can be assigned directly if the lowest-priority substituent is on a vertical bond, because it points away from us.
Otherwise, if the lowest-priority substituent is on a horizontal bond, the arrangement of the 1st, 2nd, and 3rd-priority substituents must be reversed before assigning the configuration.
The R/S assignments can be used to determine whether molecules are enantiomers or diastereomers.

108. Nomenclature 4 Lecture PowerPoint
Naming Compounds with Common Functional Groups

109. The Basic System for Naming A Variety of Functional Groups
The name of a compound requires a suffix to be added to the root if it contains something other than halo, nitro, ether, alkene, or alkyne groups.

110. How Suffixes Are Added to a Variety of Commonly Occurring Functional Groups

111. How Suffixes Are Added to a Variety of Commonly Occurring Functional Groups continued…

112. Naming Examples
The presence of the carboxylic acid (CO2H) requires the suffix “oic acid.”
Adding a suffix generally requires first dropping the “e” from the root.
Nitriles are an exception. Notice that in butanenitrile, the “e” in “butane” is retained.

113. Number Locators
A number locator must be included in their names because ketone, alcohol, and amine functional groups can appear at different locations along a carbon chain, thus leading to constitutional isomers.

114. Examples Using Number Locators

115. Carboxylic Acids and Their Derivatives
These functional groups need no number locator because they cannot be located at various positions along a carbon chain.

116. Multiple Functional Groups Corresponding to the Suffix
The usual naming rule is modified only slightly if the molecule contains multiple functional groups of the type corresponding to the suffix.

117. Some Naming Examples

118. Nomenclature Rules for Esters
Because the two alkyl groups (R and R’) can consist of any number of carbon atoms, the name of the ester must accurately describe both.
The name of an ester has the general form alkyl alkanoate.
The alkanoate portion derives from the analogous alkane having the same number of carbons.

119. Ester Examples
In ethyl butanoate, the alkanoate group is named butanoate because it is made up of a four-carbon chain.
In propyl ethanoate (propyl acetate), the alkyl group is a propyl group and the alkanoate group has two C atoms.

120. Numbering Systems for Functional Groups that Require a Suffix
In 2-ethylpentanoic acid, the longest chain of carbons containing the carboxylic acid group has five carbons. The ethyl group on C2 is treated as a substituent.

121. More Examples

122. Alkyl Groups Bonded to Nitrogen in Amines and Amides
The nitrogen atom of an amine can be bonded to two, one, or zero hydrogen atoms.
This gives rise to structures of the form RNH2, R2NH, and R3N, respectively.

123. Examples for Naming Alkyl Groups Bonded to Nitrogen in Amines continued…
In the molecule on the right, the two ethyl groups attached to N are indicated by the N,N-diethyl prefix.

124. Examples for Naming Alkyl Groups Bonded to Nitrogen in Amides
This molecule is a propanamide because the carbon chain that contains the amide group consists of three C atoms. The 2,2-dichloro prefix indicates the two Cl atoms attached to the main chain, whereas the N-propyl identifies the propyl group attached to N.

125. Examples for Naming Alkyl Groups Bonded to Nitrogen in Amides continued…
This molecule is a butanamide because the longest carbon chain containing the amide group has four C atoms. The N-cyclopentyl prefix identifies the cyclopentyl group attached to N, and the N,3-dimethyl prefix indicates that there are two methyl groups—one attached to N and the other attached to C3 of the main chain.

126. Alkene or Alkyne Having a Functional Group That Calls for a Suffix
In propenoic acid, the longest carbon chain has three atoms. The root must be changed to propene.
To indicate the presence of the carboxylic acid, the final “e” from propene is dropped, and the suffix “oic acid” is added, yielding propenoic acid as the IUPAC name.

127. Alkene or Alkyne Having a Functional Group That Calls for a Suffix continued…

128. Stereochemistry and Functional Groups That Require a Suffix
On C3, the groups we must consider are H3C- and CH3O-, and on C2 those groups are H-and the aldehyde group. The CH3O- group is the higher-priority group on C3, and the aldehyde group is the higher-priority group on C2.
Because these two groups are on the same side of the double bond, the configuration is Z.

129. The Hierarchy of Functional Groups
IUPAC has determined a hierarchy of functional groups to eliminate any potential nomenclature conflicts.

130. Examples of Functional Group Priority

131. Examples of Functional Group Priority continued…

132. Hierarchy of Functional Groups in Nomenclature

133. Hierarchy of Functional Groups in Nomenclature continued…

134. Summary of the Hierarchy
The priority for aldehyde C is greater than the alcohol C.

135. Trivial Names of Carboxylic Acids

136. Trivial Names of Carboxylic Acids continued…

137. The Greek Lettering System for Carboxylic Acids

138. Trivial Names of Carboxylic Acid Derivatives

139. Trivial Names of Aldehydes

140. Trivial Names of Ketones

141. Primary, Secondary, and Tertiary

142. Trivial Names of Alcohols

143. Trivial Names of Amines

144. More Trivial Names

145. Aromatic Trivial Names

146. Summary and Conclusions
Adding a suffix generally requires first dropping the “e” from the root.
A number locator is generally required in the name of a ketone, alcohol, or amine because those functional groups can appear at different locations along a carbon chain, thus leading to constitutional isomers.
Carboxylic acids and their derivatives need no number locator because those functional groups cannot be located at various positions along a carbon chain.

147. Summary and Conclusions continued…
Naming alkyls attached amines and amides is shown by the prefix N-.
There is a functional group hierarchy that helps name compounds with multiple functional groups.
A variety of trivial names exists for many types of functional groups.