Naming Organic Compounds

Naming Organic Compounds

H H H H H H H H | | | | | | | | H - C - C - C - C - C - C - C - C - H | | | | | | | H H H H H H H H H H | | | H - C - C - C - C - H | | | HH H H - C - H | H - C - H | H Here’s a structural diagram of a typical hydrocarbon It has 14 C’s and 30 H’s so the formula is C14H30 since each C is surrounded by 4 bonds typically, for ease of drawing, the H’s are left out to form a carbon skeleton diagram

Naming Organic Compounds Find the longest continuous carbon chain. This structure is called the parent chain. To name the parent chain prefixes at the beginning of the word are used. These prefixes are determined by the number of C atoms in the parent chain. C - C - C - C - C - C - C - C | C - C- C - C | C | C This parent chain has 9 C so it starts with non. If there are no double bonds it ends with ane Nonane is the name of the parent chain

Naming Organic Compounds Find the longest continuous carbon chain. This structure is called the parent chain. If the carbon chain is 1 C starts with meth 2 C starts with eth 3 C starts with prop 4 C starts with but 5 C starts with pent 6 C starts with hex 7 C starts with hept 8 C starts with oct 9 C starts with non 10 C starts with dec C - C - C - C - C - C - C - C | C - C- C - C | C | C This parent chain has 9 C so it starts with non. If there are no double bonds it ends with ane Nonane is the name of the parent chain

5 6 7 8 9 C - C - C - C - C - C - C - C | C - C- C - C | C | C 5 4 3 2 1 Using the red numbers the 1st side chain is encountered at the 5th C 4 Next you must number the parent chain Chains can be numbered from either direction so the rule to follow states: Number the chain so the lowest possible number is used when the 1st side chain is encountered 6 3 7 8 2 Using the blue numbers the 1st side chain is encountered at the 3rd C 9 1

5 6 7 8 9 3 C side chain is called propyl 4 3 2 C side chain is called ethyl 2 1 C - C - C - C - C - C - C - C | C - C- C - C | C | C Next, identify the side chains and where they are attached Notice all side chains end inyl

5 6 7 8 9 4 3 2 1 Now lets consider the names which have been determined C - C - C - C - C - C - C - C | C - C- C - C | C | C Parent chain is nonane side chains are 3-ethyl and 5-propyl the complete name is 3-ethyl-5-propylnonane Side chains appear 1st and are always alphabetized, (ethyl before propyl), parent chain appears last

Now draw the skeleton structure for 5-butyl-6-ethyl-2-methyl decane 1st identify the parent chain 5-butyl-6-ethyl-2-methyldecane (decane means 10 C’s with no double bonds C - C - C - C - C - C - C - C - C - C Side chains are: 2-methyl (1 C attached to the 2nd C) | C | C | C | C | C | C | C 5-butyl 4 C’s attached to the 5th C 6-ethyl 2C’s attached to the 6th C

Now draw the skeleton structure for 3,3-diethyl-2,5,6-trimethylheptane 1st identify the parent chain 3,3-diethyl -2,5,6-trimethylheptane(heptane means 7C’s with no double bonds C | C | Side chains are: 3,3-diethyl (2C attached to each side of the 3rd C) C - C - C - C - C - C - C | C | C | C | C | C 2,5,6-trimethyl 1C’s attached to the 2nd, 5th and 6th C

Name the following: C C - C C | | | C - C - C - C - C - C - C - C | | | | C C C C octane Parent Chain is 2,2,3,4,7,7 hexamethyl Side Chains are 6 - ethyl Final Answer is 6 - ethyl - 2,2,3,4,7,7 - hexamethyloctane

Naming Cyclic Hydrocarbons with Side Chains What is this structure called? Number the carbons in the ring using the lowest possible numbers. CH3 5 4 1 3 2 CH3 CH3 1,2,4-trimethyl cyclopentane

Draw 2,3-diethyl-1-methylcyclohexane

Aromatics with Side-Chains CH2CH2CH3 Name? 1,3-dipropylbenzene CH2CH2CH3

Sometimes compounds are more easily named when the benzene ring is considered to be a side chain. Name? 2,2,3-trimethyl-4-phenylhexane

C C C C C C C Draw 2,3-dimethyl-2,3-diphenylpentane

Alkyl Halides-Hydrocarbons containing F, Cl, Br, I When a halogen is introduced into a hydrocarbon molecule naming proceeds as if the halogen were simply a branch. CH3CH2CHCH2CH3 | Cl is named 3-chloropentane so CH3CH2CH2CH2CH2CH2Br is named 1-bromohexane

Draw the complete structural diagram for 4-bromo-2,5-dimethylheptane H H H H H H H | | | | | | | H-C-C -- C-C - C -- C-C-H | | | | | | | H CH3 H BrCH3 H H (CH3)2CHCH2CHBrCH(CH3)2 named H H C H H C H C H H H C C H H C H H H H H Br C C H H

H H C H H H H H H H C C H C C C H H H Br H H C C H H The parent chain is Hexane the rest of it is 3 - bromo 2,5 - dimethyl, so the complete name is 3-bromo-2,5-dimethylhexane

If double bonds are present, the hydrocarbon is still named as if the halogen were absent. F-CH=CH-CH2-CH3 is named 1-fluoro-1-butene CH3-CH=CH-CH2I is 1-iodo-2-butene CH2-CH=CH-CH2 | | Br Br is named 1,4-dibromo-2-butene The condensed structural diagram for 1-chloro-6-iodo-2,4-hexadiene is

CH2-CH=CH-CH=CH-CH2 | | I Cl

Cis and Trans Isomers Molecules with double and triple bonds cannot rotate in opposite directions on each side of the double bond so when side chains, like Cl atoms for example, are attached on each side of the double bond 2 different structures are possible. cis-1,2-dichloroethene trans-1,2-dichloroethene

Name trans-2,3-dibromo-2-pentene

Addition Reaction Hydrohalogenation of Alkenes to Alkyl halides

H C C H2Cl 3

H H C C H H Cl H

H H H H C C H Cl

Addition Reaction Hydrohalogenation of an Alkene to an alkyl halide C2H4 + HCl C2H5Cl ethene chloroethane

Markovnikov’s Rule When non-identical atoms are added 2 products are theoretically possible. Experiments show only 1 main product is formed. The H atom will bond to the C atom which already has more H’s attached. x 2H’s H-CH=CH-CH3 + HBr H2C – CH – CH3 or H2C – CH –CH3 H Br Br H 2-bromopropane Main product 1-bromopropane The “rich” get “richer”

H Br Predict the product for the reaction below

Naming Organic Compounds