Establishing an international standard of naming compounds is the purpose of the IUPAC system.
To correlate each name with a unique and unambiguous structure is the goal of the system.
IUPAC refers to a molecule's longest chain of carbons connected by single bonds, whether in a continuous chain or in a ring.
All deviations are indicated by a specific set of priorities.
Alkanes are the family of saturated hydrocarbons that are composed of carbon and hydrogen.
The molecule can be in continuous chains or in rings.
The root names of organic compounds are alkanes and cycloalkanes.
The Greek or Latin prefix indicates the number of carbons in the chain.
The IUPAC system is updated frequently.
The 1993 guidelines place the position number close to the functional group designation, however, you should be able to use and recognize names in either the old or the new style.
Ask your instructor which system to use.
The substituents within Group C have the same priority.
Methoxy is what CH3O is.
The names for complex substituents are given in brackets.
The following examples show how organic compounds containing substituents from Group C are named.
Determine the root name of the chain.
The smaller number is the position number of the first substituent.
If the first substituents have the same number, then the second substituent has a smaller number.
Determine the position of each substituent.
The position numbers and names of the substituent groups should be placed in alphabetical order.
Always include a position number for each substituent.
If there is a tie, the carbon with the substituent whose name is earlier in the alphabet could be used to begin the numbering.
Because it has a higher priority than any other substituents, the C " C has a lower position number.
A substituent name is used when the chain cannot include an alkene.
Numbering can only be done on either a ring or a chain.
The alkyne has the lower position number.
The alkene takes the lower number if each has the same position number.
The group of highest priority is indicated by the name of the molecule, with priority equivalent to any other substituents.
Now that the functional groups and substituents from Groups A, B, and C have been described, a modified set of steps for naming organic compounds can be applied to all simple structures.
Name the longest continuous carbon chain that includes this group.
The lower number is assigned to the highest priority functional group.
The position of the multiple bond should be determined by the number of the first carbon.
If the molecule includes Group A functional groups, replace the last "e" with the highest prior ity functional group, and include its position number just before the name of the highest priority functional group.
The number 1 is usually omitted from the name because an aldehyde can only be on carbon 1.
The six groups derived from carboxylic acids are in decreasing priority after carboxylic acids, salts, anhydrides, esters, acyl halides, amides, and nitriles.
The alkyl name comes first, followed by the name of the carboxylate anion.
"Aromatic" compounds are derived from benzene and similar ring systems.
The process of determining the root name of the parent ring, priority, and position number of substituents, and assembling the name in alphabetical order is similar to the aliphatic nomenclature described earlier.
The root name of the ring can be changed.
A group of aromatic compounds called ketones are attached to at least one benzene ring.
phenones are compounds that are named after the group on the other side of the carbonyl.
Bicyclic compounds have two rings.
Four possible arrangements of two rings are dependent on how many atoms are shared by the two rings.
The first arrangement in which the rings do not share any atoms does not require a method to designate how the rings are put together.
Functional groups and substituents follow standard rules once the ring system is named.
The standard rules of choosing one parent ring system and describing the other ring as a substituent are followed.
The highest priority functional group is phenyl.
Benzene is larger than cyclopentane and has three substituents.
The ring system in spiro compounds is indicated by the word "spiro", followed by brackets indicating how many atoms are contained in each path around the rings, and an alkane name describing how many carbons are in the ring systems.
Numbering goes through the spiro carbon and around the second ring.