Dr. Nesma Mamdouh Bayoumy Organic Chemistry For Dental Students Dr. Nesma Mamdouh Bayoumy Lecture (1) Spring, 2015

An Introduction to Organic Compounds Chapter 1 Organic chemistry is that branch of chemistry that deals with the structure, properties, and reactions of compounds that contain carbon. Organic compounds are the compound which contains mainly carbon and hydrogen.

Hydrocarbons Saturated Unsaturated Alkanes CnH2n+2 Alkenes Alkynes

IUPAC Nomenclature The Three Basic Parts Basic Part – Suffixes The name for any organic molecule consists of three basic parts: Prefixes-Parent-Suffix Basic Part – Suffixes Suffixes on the end of the name of an organic molecule tell you what major family the molecule belongs to The suffix for an alkane is “-ane” The suffix for an alkene is “-ene” The suffix for an alkyne is “-yne”

Counting to Ten in Organic Basic Part – the Parent The “parent” part of the name tells you how many carbons are in the longest chain “main chain” of the molecule. Counting to Ten in Organic 01 = meth 02 = eth 03 = prop 04 = but 05 = pent 06 = hex 07 = hept 08 = oct 09 = non 10 = dec

Parent and suffix… The parent is named based on the number of carbons 1 carbon = “meth” So a one-carbon alkane is called methane CH4 2 carbons = “eth” So a two carbon alkane is called ethane. CH3CH3 3 carbons = “prop” So a three carbon alkane is called propane. CH3CH2CH3 4 carbons = “but” So a four carbon alkane is called butane. CH3CH2CH2CH3

Prefixes Prefixes – the Halides So name the following alkane (shown as both condensed formula and a skeletal structure) Prefixes Prefixes are any substituent attached to the main chain (parent) of the molecule. Prefixes – the Halides Chlorine is called “chloro” Fluorine is called “ Fluoro” Bromine is called “bromo” Iodine is called “iodo Answer? nine carbons + alkane family = NONANE

Putting together a name… The rules for IUPAC nomenclature include: Step 1: Find the main chain (Longest chain) Step 2: Number the main chain Step 3: Identify all prefixes and their position numbers Step 4: Write the full name: Prefixes-Parent-Suffix. Step 5: Add punctuation. Put commas between numbers (2 5 5 becomes 2,5,5) Put a hyphen between a number and a letter (2 5 5 trimethylheptane becomes 2,5,5-trimethylheptane) Successive words are merged into one word (trimethyl heptane becomes trimethylheptane)

Follow the rules… Name the following… 4-Bromoheptane 3,4-Dibromoheptane 3-Bromo-1-chloro-4-methylhexane 1,1-Dibromo-3-methyloctane 3-ethylhexane

Alkyl Groups Alkyl groups are named similarly to alkanes. If you remove a hydrogen atom from one of these you get an alkyl group. A fragment of methane, CH4, would be CH3- called “methyl” A fragment of ethane, CH3CH3, would be CH3CH2-, called “ethyl”. Example: 3-ethylhexane

IUPAC Systematic Nomenclature - Alkanes If compound has two or more chains of the same length, parent hydrocarbon is chain with greatest number of substituents. Quiz Draw Some Simple Alkanes: 2-methylpentane 3-ethylhexane

Example 1:  Write the structural formula for 2-methylpentane Start from counting the number of carbon atoms in the longest chain - pent counts 5 carbons. Are there any carbon-carbon double bonds? No – an tells you there aren't any. Now draw this carbon skeleton: Put a methyl group on the number 2 carbon atom: Write the structural formula: 2,3-dimethylbutane. 2,2-dimethylbutane. 3-ethyl-2-methylhexane. 4-bromo-3-methylhexene.

Propyl Groups There are two possible three-carbon alkyl groups to form from propane, CH3CH2CH3. The straight chain version: CH3CH2CH2- which is called “propyl” or “n-propyl” (where n stands for “normal” or straight-chained) The other possibility is to form the fragment on the central carbon: CH3CHCH3, which is called “isopropyl” Name the following molecule:

There are two options: Option 1 is highlighted in red: The red one has two branches Option 2 is highlighted in blue: The blue one has three branches Eight carbons in main chain. Octane. Three alkyl groups attached: 2-methyl 5-propyl 6-methyl Full name: 2,6-dimethyl-5-propyloctane.

Nomenclature of Substituents The name of the alkyl group followed by the name of the class of compound constitutes the common name for alcohols amines, and alkyl halides: Suffix General Formula Function Class Ol OH Alcohols al CHO Aldehydes one C=O Ketones ether -O- Ethers oate -COO- Esters oic acid -COOH Carboxylic acids amine NH2 Amines

For each of the compounds A through G shown below, enter the appropriate IUPAC suffix in the designated answer box. In the second answer box enter a number indicating the number of carbon atoms in the longest chain. Compound IUPAC suffix Chain length

Dr. Nesma Mamdouh Bayoumy Organic Chemistry For Dental Students Dr. Nesma Mamdouh Bayoumy Lecture (2) Spring, 2015

Examples:

4-chloro-5,5-dimethylhex Name the following: 3-methylpentanoic acid but-3-enoic acid 4-chloro-5,5-dimethylhex -1-en-3-ol 4-bromo-5,6-dimethylheptan-2-amine 3-ethyl-2,2,4,5-tetramethylhexane

Name the following: Hexa-1,4-diene Pent-3-en-1-yne Hexa-1,3-dien-5-yne 3,4-Dipropyl-1,3-hexadien-5-yne 4-bromo-7-methyl-2-nonene 5-fluoro-7,7-dimethyl-2,4-octadiene

Nomenclature of Cycloalkanes Cycloalkanes generally are shown as skeletal structures:

Nomenclature of Cycloalkanes Ring is the parent hydrocarbon unless the alkyl substituent has more carbons; in that case the substituent becomes the parent hydrocarbon. If only one substituent, no need to give it a number:

Examples: cyclobutylhexane propylcyclopentane 1,1,2-trimethylcyclobutane 2-chloro-1,3-dimethyl cyclohexane 3-isopropylcyclo pent-1-ene 3-ethylcyclohept-1-ene

The line formula for a cyclic compound is shown below. Give the IUPAC name Suffix Number of ring carbons The IUPAC name : 3-ethyl-5,5-dimethylcyclohept-2-en-1-one The Suffix: ONE The number of carbons: 7 carbons

A line formula for a compound is shown below. How many carbon atoms are in the root chain? Give the IUPAC name for this compound? Answer: Number of carbons 5 The IUPAC name: 4-chloro-2-ethyl-3-methylpent-4-enoic acid

Give the IUPAC name for the following 4-isopropyl-1-ethyl-2-propylcyclohexane 3-ethyl-1,5,5-trimethylcyclohexene 1-cyclohexylheptan-3-ol 4-bromo-7-chloro-3-isopropylcyclo hept-1-ene

Benzene Derivatives 1-methyl-2-propylbenzene 1-bromo-4-ethyl-2-isopropylbenzene 1,3,5-trimethylbenzene