Give The Iupac Name For The Following Compound

The IUPAC nomenclature provides a systematic way to name organic chemical compounds, ensuring clarity and consistency in scientific communication. Accurately naming a compound using IUPAC rules is crucial for identifying and understanding its chemical properties and reactions.

Understanding IUPAC Nomenclature

Before diving into specific examples, it's essential to grasp the fundamental principles of IUPAC nomenclature. The system relies on identifying the parent chain, the longest continuous chain of carbon atoms in the molecule, and then naming the substituents attached to that chain.

Key Components of an IUPAC Name:

• Parent Chain: The longest continuous chain of carbon atoms, forming the base name (e.g., methane, ethane, propane).
• Substituents: Atoms or groups of atoms attached to the parent chain (e.g., methyl, ethyl, chloro).
• Locants: Numbers indicating the position of substituents on the parent chain.
• Functional Groups: Specific groups of atoms within a molecule that are responsible for the characteristic chemical reactions of that molecule (e.g., alcohol, ketone, amine).

General Steps for Naming Organic Compounds:

1. Identify the Parent Chain: Find the longest continuous chain of carbon atoms. If there are multiple chains of the same length, choose the one with the most substituents.
2. Number the Parent Chain: Number the carbon atoms in the parent chain to give the substituents the lowest possible numbers.
3. Identify and Name the Substituents: Determine the names of the groups attached to the parent chain. Common alkyl substituents include methyl (-CH3), ethyl (-CH2CH3), and propyl (-CH2CH2CH3).
4. Arrange Substituents Alphabetically: List the substituents in alphabetical order, ignoring prefixes like di, tri, tetra, etc.
5. Combine All Components: Combine the locants, substituent names, and parent chain name into a single, coherent name.

Naming Alkanes and Alkyl Substituents

Alkanes are the simplest organic compounds, consisting only of carbon and hydrogen atoms linked by single bonds. Understanding how to name alkanes and their corresponding alkyl substituents is the foundation of IUPAC nomenclature.

Naming Straight-Chain Alkanes:

The names of straight-chain alkanes are straightforward and based on the number of carbon atoms in the chain:

• 1 carbon: Methane (CH4)
• 2 carbons: Ethane (C2H6)
• 3 carbons: Propane (C3H8)
• 4 carbons: Butane (C4H10)
• 5 carbons: Pentane (C5H12)
• 6 carbons: Hexane (C6H14)
• 7 carbons: Heptane (C7H16)
• 8 carbons: Octane (C8H18)
• 9 carbons: Nonane (C9H20)
• 10 carbons: Decane (C10H22)

Naming Alkyl Substituents:

Alkyl substituents are formed when a hydrogen atom is removed from an alkane. The name of the alkyl substituent is derived from the alkane name by changing the "-ane" ending to "-yl":

• Methane becomes Methyl (-CH3)
• Ethane becomes Ethyl (-CH2CH3)
• Propane becomes Propyl (-CH2CH2CH3)
• Butane becomes Butyl (-CH2CH2CH2CH3)

Isopropyl and sec-Butyl

Two common branched alkyl substituents have specific names:

• Isopropyl: A propyl group attached to a chain at the second carbon atom, (CH3)2CH-.
• sec-Butyl: A butyl group attached to a chain at the second carbon atom, CH3CHCH2CH3-. The sec- prefix stands for "secondary," indicating that the carbon atom attached to the main chain is bonded to two other carbon atoms.

Naming Alkenes and Alkynes

Alkenes contain at least one carbon-carbon double bond, while alkynes contain at least one carbon-carbon triple bond.

Naming Alkenes:

1. Identify the Parent Chain: Find the longest continuous carbon chain that contains the double bond.
2. Number the Parent Chain: Number the chain so that the double bond receives the lowest possible number. The position of the double bond is indicated by the number of the first carbon atom involved in the double bond.
3. Change the Suffix: Replace the "-ane" ending of the corresponding alkane name with "-ene."

For example, CH3CH=CHCH2CH3 is named 2-pentene because the longest chain containing the double bond has five carbons, and the double bond starts at the second carbon atom.

Naming Alkynes:

The process for naming alkynes is similar to that for alkenes:

1. Identify the Parent Chain: Find the longest continuous carbon chain that contains the triple bond.
2. Number the Parent Chain: Number the chain so that the triple bond receives the lowest possible number. The position of the triple bond is indicated by the number of the first carbon atom involved in the triple bond.
3. Change the Suffix: Replace the "-ane" ending of the corresponding alkane name with "-yne."

For example, CH≡CCH2CH3 is named 1-butyne because the longest chain containing the triple bond has four carbons, and the triple bond starts at the first carbon atom.

Naming Compounds with Functional Groups

Functional groups are specific atoms or groups of atoms within a molecule that are responsible for the characteristic chemical reactions of that molecule. Naming compounds with functional groups requires prioritizing the functional group in the numbering and using specific suffixes.

Common Functional Groups and Their Suffixes:

• Alcohols (-OH): Suffix "-ol". Example: Ethanol (CH3CH2OH)
• Aldehydes (-CHO): Suffix "-al". Example: Ethanal (CH3CHO)
• Ketones (-CO-): Suffix "-one". Example: Propanone (CH3COCH3)
• Carboxylic Acids (-COOH): Suffix "-oic acid". Example: Ethanoic acid (CH3COOH)
• Amines (-NH2): Suffix "-amine". Example: Ethylamine (CH3CH2NH2)
• Ethers (-O-): Named using alkoxy substituents (e.g., methoxy, ethoxy). Example: Methoxyethane (CH3OCH2CH3)
• Esters (-COOR): Named as alkyl alkanoates. Example: Ethyl ethanoate (CH3COOCH2CH3)
• Amides (-CONH2): Suffix "-amide". Example: Ethanamide (CH3CONH2)

Priorities of Functional Groups

When a molecule contains multiple functional groups, a priority order determines which group is named with the suffix and which are named as substituents. A simplified priority order is:

Carboxylic acids > Esters > Aldehydes > Ketones > Alcohols > Amines > Ethers > Alkenes/Alkynes > Alkanes

For example, if a molecule contains both an alcohol and a ketone, the ketone will be named as a substituent ("oxo-") and the alcohol will be given the "-ol" suffix.

Cyclic Compounds

Cyclic compounds contain a ring of carbon atoms. Naming them requires using the prefix "cyclo-" before the alkane name corresponding to the number of carbon atoms in the ring.

Naming Simple Cycloalkanes:

• Cyclopropane (C3H6)
• Cyclobutane (C4H8)
• Cyclopentane (C5H10)
• Cyclohexane (C6H12)

Naming Substituted Cycloalkanes:

1. Number the Ring: Number the carbon atoms in the ring to give the substituents the lowest possible numbers. If there is only one substituent, it is automatically assigned position 1.
2. List Substituents Alphabetically: List the substituents in alphabetical order, including their locants.

For example, 1-ethyl-3-methylcyclohexane.

Stereochemistry: cis, trans, E, and Z

Stereochemistry deals with the spatial arrangement of atoms in molecules. Cis and trans are used to describe the relative positions of substituents on rings or across double bonds, while E and Z are used for alkenes with more complex substitution patterns.

cis and trans:

• cis-: Indicates that two substituents are on the same side of a ring or double bond.
• trans-: Indicates that two substituents are on opposite sides of a ring or double bond.

For example, cis-1,2-dimethylcyclohexane has both methyl groups on the same side of the cyclohexane ring.

E and Z:

The E and Z nomenclature is used to describe the stereochemistry of alkenes when the cis and trans nomenclature is ambiguous.

1. Assign Priorities: For each carbon atom of the double bond, assign priorities to the two substituents based on the Cahn-Ingold-Prelog (CIP) priority rules (based on atomic number). The atom with the higher atomic number receives the higher priority.
2. Determine Relative Positions:
   • Z- (from the German zusammen, meaning "together"): If the two higher priority groups are on the same side of the double bond.
   • E- (from the German entgegen, meaning "opposite"): If the two higher priority groups are on opposite sides of the double bond.

For example, (Z)-2-bromo-2-butene.

Examples with Detailed Explanations

Let's work through some examples to solidify understanding of the IUPAC nomenclature rules.

Example 1:

CH3CH2CH(CH3)CH2CH2CH3

1. Parent Chain: The longest continuous chain has six carbon atoms (hexane).
2. Numbering: Number the chain from left to right to give the methyl group the lowest possible number (3).
3. Substituent: A methyl group (-CH3) at position 3.
4. Name: 3-methylhexane

Example 2:

CH3CH=CHCH2CH3

1. Parent Chain: The longest continuous chain containing the double bond has five carbon atoms (pentene).
2. Numbering: Number the chain from left to right to give the double bond the lowest possible number (2).
3. Name: 2-pentene

Example 3:

CH3CH2COCH3

1. Parent Chain: The longest continuous chain containing the ketone group has four carbon atoms (butanone).
2. Numbering: Number the chain from left to right to give the ketone group the lowest possible number (2).
3. Name: 2-butanone

Example 4:

CH3CH(OH)CH2CH3

1. Parent Chain: The longest continuous chain containing the alcohol group has four carbon atoms (butanol).
2. Numbering: Number the chain from left to right to give the alcohol group the lowest possible number (2).
3. Name: 2-butanol

Example 5:

CH3CH2CH2COOH

1. Parent Chain: The longest continuous chain containing the carboxylic acid group has four carbon atoms (butanoic acid).
2. Numbering: The carboxylic acid group is always at position 1, so no number is needed.
3. Name: Butanoic acid

Example 6:

(CH3)2CHCH2CH=CHCH3

1. Parent Chain: The longest continuous chain containing the double bond has six carbon atoms (hexene).
2. Numbering: Number the chain from right to left to give the double bond the lowest possible number (2).
3. Substituents: A methyl group at position 5. Note that the (CH3)2CH- is an isopropyl group.
4. Name: 5-methyl-2-hexene

Example 7:

      Cl
      |
CH3-CH-CH2-CH=CH-CH3

1. Parent Chain: The longest continuous chain containing the double bond has six carbon atoms (hexene).
2. Numbering: Number the chain from right to left to give the double bond the lowest possible number (2).
3. Substituent: A chloro group (-Cl) at position 5.
4. Name: 5-chloro-2-hexene

Example 8:

     CH3
      |
CH3-CH-CH2-CH2-OH

1. Parent Chain: The longest continuous chain containing the alcohol group has five carbon atoms (pentanol).
2. Numbering: Number the chain from right to left to give the alcohol group the lowest possible number (1).
3. Substituent: A methyl group (-CH3) at position 4.
4. Name: 4-methyl-1-pentanol

Example 9:

     Br   Cl
      |    |
CH3-CH-CH-CH3

1. Parent Chain: The longest continuous chain has four carbon atoms (butane).
2. Numbering: Number the chain from left to right to give the substituents the lowest possible numbers. Since both directions would give the substituents positions 2 and 3, we prioritize numbering to give the substituent that comes first alphabetically the lowest number. Therefore, we number from left to right.
3. Substituents: A bromo group (-Br) at position 2 and a chloro group (-Cl) at position 3.
4. Name: 2-bromo-3-chlorobutane

Example 10:

     CH3
      |
CH3-C=CH-CH3
      |
     CH3

1. Parent Chain: The longest continuous chain containing the double bond has four carbon atoms (butene).
2. Numbering: Number the chain from either direction to give the double bond the lowest possible number (2).
3. Substituents: Two methyl groups (-CH3) at position 2.
4. Name: 2,3-dimethyl-2-butene

Example 11: A cyclic compound:

     CH3
      |
  /       \
 /         \
|           |
|           |
 \         /
  \       /
    CH2
    |
    CH3

1. Parent Chain: This is a cyclohexane ring.
2. Numbering: Start numbering at the ethyl group (since ethyl comes before methyl alphabetically).
3. Substituents: An ethyl group at position 1 and a methyl group at position 3.
4. Name: 1-ethyl-3-methylcyclohexane

Advanced Concepts and Considerations

While the basic rules of IUPAC nomenclature cover a wide range of organic compounds, there are more advanced concepts to consider for complex molecules.

Bridged and Spiro Compounds

Bridged and spiro compounds are polycyclic compounds with specific ring junctions. Naming these compounds requires special prefixes and numbering systems.

Functional Group Derivatives

Derivatives of common functional groups, such as acid halides, anhydrides, and nitriles, have specific naming conventions.

Trivial Names

Some common organic compounds retain their "trivial" or common names (e.g., acetone, benzene) even though systematic IUPAC names exist. While IUPAC names are preferred for clarity, trivial names are often used in specific contexts.

Common Mistakes to Avoid

Accurate IUPAC naming requires careful attention to detail. Here are some common mistakes to avoid:

• Incorrectly Identifying the Parent Chain: Always find the longest continuous chain, even if it's not immediately obvious.
• Incorrect Numbering: Ensure that the principal functional group and substituents receive the lowest possible numbers.
• Forgetting to Alphabetize Substituents: Substituents must be listed in alphabetical order, ignoring prefixes like di, tri, and tetra.
• Ignoring Stereochemistry: When applicable, include stereochemical descriptors like cis, trans, E, and Z.
• Using Incorrect Prefixes and Suffixes: Ensure that you are using the correct prefixes and suffixes for the functional groups present in the molecule.
• Not Recognizing Functional Group Priority: When multiple functional groups are present, make sure to name the compound according to the appropriate priority.
• Not Paying Attention to Punctuation: Use commas to separate numbers and hyphens to separate numbers from words.

Resources for Further Learning

• IUPAC Nomenclature of Organic Chemistry: Blue Book: The definitive guide to IUPAC nomenclature.
• Online IUPAC Naming Tools: Many websites and software programs can help you generate IUPAC names from chemical structures and vice versa.
• Textbooks on Organic Chemistry: Most organic chemistry textbooks include detailed explanations of IUPAC nomenclature.
• Online Chemistry Forums and Communities: Participating in online forums and communities can provide opportunities to ask questions and learn from others.

Conclusion

Mastering IUPAC nomenclature is essential for anyone studying or working in chemistry. By understanding the fundamental principles and practicing regularly, you can confidently name and interpret the names of a wide variety of organic compounds. This systematic approach ensures clear communication and understanding in the chemical sciences. Remember to always double-check your work and consult reliable resources when needed. With practice and dedication, you can master the art of IUPAC nomenclature.