Systematic Nomenclature of Organic Compounds PDF

Bicol University Guinobatan Chem 11 Organic Chemistry Systematic Nomenclature of Organic Compounds Hannah Angelie H. Olivarez, RCh  TABLE OF CONTENTS 01 02 Overview of IUPAC Steps in IUPAC Naming Nomenclature 03 04 P...

Bicol University Guinobatan Chem 11 Organic Chemistry Systematic Nomenclature of Organic Compounds Hannah Angelie H. Olivarez, RCh  TABLE OF CONTENTS 01 02 Overview of IUPAC Steps in IUPAC Naming Nomenclature 03 04 Prefixes, Roots, and Naming Examples Suffixes Review: Formula Types of Formula Displayed Formula 01 Empirical Formula 04 (Full Structural Formula) 02 Molecular Formula 05 Skeletal Formula Structural Formula Stereochemical 03 (Condensed Structural 06 Formula Formula) Empirical Formula Molecular Formula The molecular formula of an organic compound simply shows Simplest formula that shows the the number of each type of atom ratio of number of atoms of the present. It tells you nothing elements present in one about the bonding within the molecule compound. Example: Lactic acid Example: Lactic acid CH2O C 3 H 6 O3 Structural Formula (Condensed Structural Formula) Shows how the constituent atoms of a molecule are Example: joined together with Lactic acid minimal detail using conventional groups. CH3CH(OH)CO2H All the atoms attached to a 2-methylpropene particular carbon atom are CH2C(CH3)2 written immediately after that carbon atom Full Structural Formula (Displayed Formula) Detailed structure of a molecule showing the relative placing of atoms and the Example: number & type of bonds between them One of the common mistake students often made is the omission of O-H bonds for the hydroxyl functional group For ring structures (including benzene rings), all the C and H atoms (and their related bonds) can be omitted Skeletal Formula Simplified organic formula by Example: Lactic acid removing hydrogen atoms from alkyl chains, leaving just the carbon skeleton and associated functional groups Each C-C bond in the carbon skeleton is a line (each end is a carbon atom) Double and triple lines indicate double and triple bonds respectively Stereochemical Formula Shows the three-dimensional spatial arrangement of bonds, atoms and groups around a key part Example: Lactic acid of a molecule (usually a stereochemical centre) Solid wedges indicate bonds to an atom pointing out of the plane of the paper Dashed wedges or hashed lines indicate bonds to an atom pointing into the plane of the paper Normal straight lines indicate bonds on the plane of the paper Fischer Projections Fischer projections show sugars in their open chain form. the carbon atoms of a sugar molecule are connected vertically by solid lines, while carbon-oxygen and carbon-hydrogen bonds are shown horizontally. Haworth Projections Haworth projections are often used to depict sugars in their cyclic forms.  Review: Classes of Organic Compounds!  Overview of IUPAC 01 Nomenclature  IUPAC Nomenclature The International Union of Pure and Applied Chemistry (IUPAC) system is used for naming organic compounds in a systematic way. This ensures that each compound has a unique, unambiguous name.  Basic Components of IUPAC Names: 01 02 03 Prefix Suffix Identifies Denotes the primary substituents and Root functional group of their positions on Describes the the molecule. the main chain. longest carbon chain (parent chain) in the molecule. Prefixes for Alkyl Groups (Substituents) These are used to name side chains (hydrocarbon groups attached to the parent chain): Methyl- (–CH₃) Ethyl- (–C₂H₅) One carbon substituent Two carbon substituent Example: 2-Methylpentane Example: 2-Ethylhexane Propyl- (–C₃H₇) Isopropyl- (–CH(CH₃)₂) Three carbon substituent Branched form of a Example: 3-Propylheptane three-carbon group Example: 3-Isopropylpentane Prefixes for Alkyl Groups (Substituents) These are used to name side chains (hydrocarbon groups attached to the parent chain): Butyl- (–C₄H₉) Sec-butyl- (–CH(CH₃)CH₂CH₃) Four carbon substituent Branched four carbon group attached Example: 2-Butylhexane at the second carbon Example: 2-Sec-butylpentane Tert-butyl- (–C(CH₃)₃) Four carbon group attached at a tertiary carbon Example: 2-Tert-butylpentane Prefixes for Halogens (Halide Substituents) Halogen atoms can replace hydrogen atoms in organic compounds: Fluoro- (–F) Chloro- (–Cl) Fluorine substituent Chlorine substituent Example: 2-Fluoropropane Example: 1-Chlorobutane Bromo- (–Br) Iodo- (–I) Bromine substituent Iodine substituent Example: 2-Bromopentane Example: 1-Iodohexane Prefixes for Nitrogen-containing Groups Nitrogen atoms may appear in organic compounds in the form of various functional groups: Amino- (–NH₂) Nitro- (–NO₂) Amine group substituent Nitro group substituent Example: 2-Aminobutane Example: 1-Nitropropane Prefixes for Oxygen-containing Groups These groups often affect the physical properties of the compound: Hydroxy- (–OH) Alkoxy- (–OR) Hydroxyl group, typically for An ether group, where R is an alcohols or phenols when it is alkyl group (e.g., methoxy, not the main functional group ethoxy) Example: 2-Hydroxybutanoic Example: Ethoxyethane (common acid name: diethyl ether) Prefixes for Multiple Substituents (Indicating Quantity) When multiple identical substituents are present, the following prefixes are used: Di- Tri- Two identical groups Three identical groups Example: 2,3-Dimethylbutane Example: 1,1,1-Trichloroethane (two methyl groups at (three chlorine atoms at position 1) positions 2 and 3) Tetra- Four identical groups Example: Tetrachloromethane (four chlorine atoms on a methane backbone) Prefixes for Cyclic Compounds When the main carbon chain forms a ring, the prefix cyclo- is used: Cyclo- Indicates a ring structure Example: Cyclohexane (a six-carbon ring)  Prefixes for Carbonyl-containing Functional Groups Carbonyl groups (C=O) appear in various functional groups like aldehydes, ketones, carboxylic acids, etc.: Formyl- (–CHO) Oxo- (C=O) Aldehyde group attached as Ketone group used when it is asubstituent not the primary functional Example: 4-Formylbenzoic acid group Example: 2-Oxopentanoic acid  Prefixes for Isomeric Variants For isomers, some prefixes are used to indicate the structure or branching pattern: Iso- Neo- Indicates branching, usually near the Indicates a specific branching end of the chain pattern, usually for five-carbon (commonly used with alkanes) alkanes Example: Isopropyl alcohol Example: Neopentane (common name for 2-propanol) Sec- (secondary) Tert- (tertiary) Substituent attached to a secondary Substituent attached to a tertiary carbon carbon (a carbon attached to (a carbon attached to two other three other carbons) carbons) Example: Tert-butyl alcohol Example: Sec-butyl chloride  Steps in IUPAC 02 Naming  HIGHLIGHTS OF THE MONTH Step 1 Identify the longest carbon 01 Step 2 chain (parent chain). 02 Number the chain so that the substituents have the lowest possible numbers. Step 4 Combine the name of the 04 03 Step 3 Name and number the substituent with the parent substituents (prefixes). chain and use the correct suffix to indicate the main functional group.  Naming Alkanes (Saturated Hydrocarbons) General formula: CₙH₂ₙ₊₂ Suffix: "-ane" Example 1: Hexane Longest chain: 6 carbons No substituents IUPAC name: Hexane  Naming Alkanes (Saturated Hydrocarbons) General formula: CₙH₂ₙ₊₂ Suffix: "-ane" Example 2: 2-Methylpentane Longest chain: 5 carbons (pentane) One methyl (CH₃) substituent at position 2 IUPAC name: 2-Methylpentane  Naming Alkenes (Unsaturated Hydrocarbons with Double Bonds) General formula: CₙH₂ₙ Suffix: "-ene" The double bond gets the lowest possible number in the chain. Example 1: But-2-ene Longest chain: 4 carbons (butane) Double bond between C2 and C3 IUPAC name: But-2-ene  Naming Alkenes (Unsaturated Hydrocarbons with Double Bonds) General formula: CₙH₂ₙ Suffix: "-ene" The double bond gets the lowest possible number in the chain. Example 2: 3-Methylpent-1-ene Longest chain: 5 carbons with a double bond starting at C1 Methyl group at C3 IUPAC name: 3-Methylpent-1-ene  Naming Alkynes (Unsaturated Hydrocarbons with Triple Bonds) General formula: CₙH₂ₙ₋₂ Suffix: "-yne" Triple bond gets the lowest number. Example 1: Ethyne Longest chain: 2 carbons (ethane) Triple bond between C1 and C2 IUPAC name: Ethyne (common name: acetylene)  Naming Alkynes (Unsaturated Hydrocarbons with Triple Bonds) General formula: CₙH₂ₙ₋₂ Suffix: "-yne" Triple bond gets the lowest number. Example 2: 3-Methylbut-1-yne Longest chain: 4 carbons with a triple bond starting at C1 Methyl group at C3 IUPAC name: 3-Methylbut-1-yne  Naming Alcohols (–OH Functional Group) General formula: R–OH Suffix: "-ol" The hydroxyl group gets the lowest possible number. Example 1: Propan-2-ol Longest chain: 3 carbons (propane) Hydroxyl group at C2 IUPAC name: Propan-2-ol (common name: isopropyl alcohol)  Naming Alcohols (–OH Functional Group) General formula: R–OH Suffix: "-ol" The hydroxyl group gets the lowest possible number. Example 2: 2-Methylbutan-1-ol Longest chain: 4 carbons (butane) Hydroxyl group at C1 Methyl group at C2 IUPAC name: 2-Methylbutan-1-ol  Naming Alcohols (–OH Functional Group) General formula: R–OH Suffix: "-ol" The hydroxyl group gets the lowest possible number. Example 2: 2-Methylbutan-1-ol Longest chain: 4 carbons (butane) Hydroxyl group at C1 Methyl group at C2 IUPAC name: 2-Methylbutan-1-ol  Naming Aldehydes (–CHO Functional Group) Suffix: "-al" The carbonyl group (C=O) is always at the end of the carbon chain. Example 1: Butanal Longest chain: 4 carbons Aldehyde group at C1 IUPAC name: Butanal  Naming Aldehydes (–CHO Functional Group) Suffix: "-al" The carbonyl group (C=O) is always at the end of the carbon chain. Example 2: 3-Methylbutanal Longest chain: 4 carbons Methyl group at C3 IUPAC name: 3-Methylbutanal  Naming Ketones (–C=O Functional Group) Suffix: "-one" The carbonyl group (C=O) is located within the carbon chain. Example 1: Pentan-2-one Longest chain: 5 carbons Carbonyl group at C2 IUPAC name: Pentan-2-one  Naming Ketones (–C=O Functional Group) Suffix: "-one" The carbonyl group (C=O) is located within the carbon chain. Example 2: 4-Methylpentan-2-one Longest chain: 5 carbons Methyl group at C4 Carbonyl group at C2 IUPAC name: 4-Methylpentan-2-one  Naming Carboxylic Acids (–COOH Functional Group) Suffix: "-oic acid" The carboxyl group is always at the end of the carbon chain. Example 1: Ethanoic acid Longest chain: 2 carbons Carboxyl group at C1 IUPAC name: Ethanoic acid (common name: acetic acid)  Naming Carboxylic Acids (–COOH Functional Group) Suffix: "-oic acid" The carboxyl group is always at the end of the carbon chain. Example 2: 3-Methylbutanoic acid Longest chain: 4 carbons Methyl group at C3 Carboxyl group at C1 IUPAC name: 3-Methylbutanoic acid  Naming Esters (–COOR Functional Group) Suffix: "-oate" Esters are named as derivatives of carboxylic acids, with the alcohol part as a prefix. Example 1: Methyl ethanoate Parent carboxylic acid: Ethanoic acid (CH₃COOH) Alcohol group: Methanol (CH₃OH) IUPAC name: Methyl ethanoate  Naming Esters (–COOR Functional Group) Suffix: "-oate" Esters are named as derivatives of carboxylic acids, with the alcohol part as a prefix. Example 2: Ethyl butanoate Parent carboxylic acid: Butanoic acid Alcohol group: Ethanol IUPAC name: Ethyl butanoate Practice Exercises 1. CH₃CH₂CH₂CH₃ 2. CH₃CH(CH₃)CH₂CH₃ 3. CH₂=CH–CH₃ 4. CH₃C≡CCH₃ 5. CH₃CH₂CH₂OH 6. CH₃CH₂CHO 7. CH₃COCH₃ 8. CH₃CH₂CH₂COOH 9. CH₃CH₂COOCH₃ Practice Exercises 1. Butane 2. 2-Methylbutane 3. Prop-1-ene 4. But-2-yne 5. Propan-1-ol 6. Propanal 7. Propan-2-one 8. Butanoic acid 9. Methyl propanoate Draw the structures for the following compounds: 1. 2-Methylhexane 2. Pentan-3-one 3. Ethyl propanoate 4. 2-Butanol 5. 3-Methylbutanoic acid  Common Mistakes and Tips 02 Omitting the position of the functional group. Always specify the location of the 01 double/triple bonds and Not assigning the lowest substituents. possible number to the functional group 03 Incorrect: But-3-ene for Ignoring the priority of But-1-ene. functional groups. The functional group with the highest priority should dictate the suffix of the molecule. THANKS Do you have any questions? CREDITS: This presentation template was created by Slidesgo, including icons by Flaticon, and infographics & images by Freepik