Organic Chemistry a branch of chemistry concerned with the study of carbon and its compounds.

Hydrocarbons the simplest class of organic compounds containing carbon & hydrogen only hydrocarbons aromatic aliphatic alkanes cycloalkanes alkenes alkynes

Aliphatic Hydrocarbons A hydrocarbon with no aromatic ring Example:

Aromatic Hydrocarbons a hydrocarbon containing one or more rings with delocalized  electron systems (example is benzene, C6H6)

Alkanes are saturated hydrocarbons general formula is CnH2n+2 ex: CH4 (methane) single covalent bonds (C-C) between carbon to carbon molecules are present uses the –ane ending in its name

Alkanes The first 10 alkanes are named as follows: CH4 methane C6H14 hexane C2H6 ethane C7H16 heptane C3H8 propane C8H18 octane C4H10 butane C9H20 nonane C5H12 pentane C10H22 decane

Cycloalkanes alkanes whose carbon atoms are joined in rings  general formula is CnH2n ex: C6H12 (cyclohexane) uses the prefix cyclo and –ane ending in its name

Alkenes (Olefins) unsaturated hydrocarbons that contain C=C general formula is CnH2n (same as cyloalkane) ex:C2H4 (ethene) uses the –ene ending in its name

Alkynes (Paraffins) unsaturated hydrocarbons that contain CC general formula is CnH2n-2 ex: C2H2 (ethyne) uses the –yne ending in its name

Important Notes an alkane less one hydrogen atom is called an alkyl group (example is when a hydrogen atom is removed from methane, it is called methyl, -CH3)

Naming Alkanes Step 1: Determine the parent name by finding the longest continuous chain of carbon atoms in the molecule. The parent name is the name of the alkane corresponding to the longest continuous carbon chain. The longest chain may not be always written horizontally.

Naming Alkanes C H 3 1 2 4 5 6 hexane 3 – methylhexane

Naming Alkanes If the molecule contains two chains of equal length, choose the one with the greater number of substituents as the parent chain.

Naming Alkanes  Step 2 name each substituent and precede this name with the number of carbon atom on the parent chain to which it is bonded.

Naming Alkanes Parent: butane Substituent: methyl Location: C2- methyl   Parent: butane Substituent: methyl Location: C2- methyl Name: 2 – methylbutane

Naming Alkanes Two or more identical substituents present in a molecule are indicated by the use of the prefixes di for 2, tri for 3 tetra for 4, etc. Each of the identical substituents must have a number

Naming Alkanes Parent: butane Substituent: methyl Location: C2 and C3- methyl Name: 2,3 –dimethylbutane

Naming Alkanes When two or more substituents are present, their names are listed in alphabetical order

Naming Alkanes Parent: heptane Substituent: methyl and ethyl   Parent: heptane Substituent: methyl and ethyl Location: C2- methyl and C3- ethyl Name: 3 – ethyl – 2 – methylheptane Note: the name of the compound is written in single word.

Naming Alkenes & Alkynes Step 1: Choose the longest continuous carbon chain that contains the double/triple bond as the parent chain. Step 2: Number the chain to give the lowest number to the first carbon of the double/triple bond.

Naming Alkenes & Alkynes Step 3: Substitute the ending -ene for ending –ane in the name of the corresponding alkane to obtain the parent alkene name and substitute –yne to obtain the parent alkyne. The position of the double/triple bond is indicated by a number. Step 4: Write the complete name of the compound with the correct number of all substituents, which are listed in alphabetical order.

Examples Parent: octene Location: C3 Substituent: methyl, ethyl & bromo Location: C3,C6- methyl; C4 bromo; C6-ethyl Name:4-Bromo–6-ethyl-3,6-dimethyl-3-octene

Examples Parent: butyne Location: C1 Substituent: methyl Location: C3 Name: 3 – methyl – 1- butyne or 3- methylbutyne

Aromatics: Benzene Monosubstituted benzenes are named by combining the substituent name w/ the word benzene. Name: 1 - ethylbenzene

For disubstituted benzenes the 3 possible isomers are named using the prefixes ortho (o), meta (m) & para (p) to designate the 1,2 – 1,3 & 1,4 –relationships of sustituents on the benzene ring: Name: 1,3-Dibromobenzene or meta-Dibromobenzene

Exercises: Draw the structure of the following hydrocarbons: 2,2-dimethylpentane 4-ethyl-2,3-dimethyloctane 3-ethyl-3-methyl-1-pentene 1,3- dibromobenzene

Exercises: Give the name of the following Hydrocarbons: 1. 2.

3. 4. 5. 6.

Hydrocarbon Derivatives these are compounds that are formed when one, two or three hydrogen atoms in the hydrocarbon molecules are replaced by atoms or group of atoms that are responsible for the properties of that compound. This group of atoms is called the functional group.

ALCOHOLS Contains the –OH group (hydroxyl) ex: CH3-OH methanol CH3CH2-OH ethanol phenol

Some Typical Alcohols “rubbing alcohol” CH3CHCH3 2-propanol (isopropyl alcohol) antifreeze HO-CH2-CH2-OH 1,2-ethanediol (ethylene glycol) glycerol HO-CH2-CH-CH2OH Anti-freeze

Ethers Contain an -O- between two carbon groups CH3-O-CH3 dimethyl ether CH3-O-CH2CH3 ethyl methyl ether

Aldehydes and Ketones O carbonyl group In an aldehyde, an H atom is attached to a carbonyl group O carbonyl group  CH3-C-H In a ketone, two carbon groups are attached to a carbonyl group CH3-C-CH3

Aldehydes as Flavorings

Ketones O O   Butter flavor CH3-C-C-CH3 butanedione propanone

Amines Organic compounds of nitrogen N Classified as primary, secondary, tertiary CH3 CH3   CH3—NH2 CH3—NH CH3—N — CH3 1° 2° 3°

Alkaloids Physiologically active nitrogen-containing compounds Obtained from plants Used as anesthetics, antidepressants, and stimulants Many are addictive

Some Common Amines

Some Common Amines

Carboxylic Acid Carboxylic acids contain the carboxyl group on carbon 1. O  CH3 — C—OH CH3—COOH carboxyl group

Some Carboxylic Acids & their Names Citric acid Aspirin

Amides Derivatives of carboxylic acids where an amino (-NH2) group replaces the –OH group. O O   CH3 — C—OH CH3 — C—NH2 carboxylic acid amide acetic acid acetamide

Some Amides & their Names  CH3C–NHCH3 N-methylethanamide (IUPAC) N-methylacetamide (common)

Esters In an ester, the H in the carboxyl group is replaced with an alkyl group O  CH3 — C—O —CH3 CH3—COO —CH3 ester group

Esters in Plants Esters give flowers and fruits their pleasant fragrances and flavors.

Some Esters and Their Names Flavor/Odor Raspberries HCOOCH2CH3 ethyl methanoate (IUPAC) ethyl formate (common) Pineapples CH3CH2CH2 COOCH2CH3 ethyl butanoate (IUPAC) ethyl butyrate (common)

Exercises: Identify the functional groups present in the following compounds: (2) (4) (1) (3)

(7) (5) (8) (6)