Turn on thread page Beta
    • Thread Starter
    Offline

    3
    ReputationRep:
    What is the name of this compound?

    CH2(OH)CH2C(CH3)=CHCH2CH3

    Thanks/
    Offline

    0
    ReputationRep:
    What is the longest carbon chain?
    What does the double bond make the name; where is it?
    The OH cant be at the end since we have -ene so put use hydroxy at the beginning and it's position.
    Offline

    0
    ReputationRep:
    6-hydroxy-4-methylhex-3-ene
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by canI?)
    6-hydroxy-4-methylhex-3-ene
    But having OH makes it alcohol, doesn't it?
    • Community Assistant
    • Study Helper
    Offline

    17
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by SWEngineer)
    But having OH makes it alcohol, doesn't it?
    It has both an alkene group (-ene) and an alcohol group (hydroxy or ol).

    The ene takes priority as the suffix, so the alcohol prefix (hydroxy- ) is used.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by charco)
    It has both an alkene group (-ene) and an alcohol group (hydroxy or ol).

    The ene takes priority as the suffix, so the alcohol prefix (hydroxy- ) is used.
    So, can we say it is: 1-hydroxy-3-methylhexene?
    Offline

    0
    ReputationRep:
    (Original post by SWEngineer)
    So, can we say it is: 1-hydroxy-3-methylhexene?
    You'll name from the shortest way to reach the alkene functional group, so it'll be as stated before:

    6-hydroxy-4-methylhex-3-ene

    Naming it your wat would get 1-hydroxy-3-methylhex-4-ene

    You also need to say which carbon the double bond occurs at because it isnt situated at the end of the long chain but in the middle. You number the functional group via the shortest route from the main group, in this case the alkene group
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by charco)
    No, the double bond takes number priority (it's the suffix to the root) and you have to state its position:

    6-hydroxy-4-methylhex-3-ene

    exactly as canI? says
    Why isn't it 1-hydroxy-3-methyl-3-hexene?

    Why are you inserting 6-hydroxy?

    Here, I think counting from either direction, left to right and vice versa gives the same as to the less number to reach the double bond. And, thus, if we count from left to right for example, OH will be on the first carbon.

    What do you think?
    Offline

    0
    ReputationRep:
    (Original post by SWEngineer)
    Why isn't it 1-hydroxy-3-methyl-3-hexene?

    Why are you inserting 6-hydroxy?

    Here, I think counting from either direction, left to right and vice versa gives the same as to the less number to reach the double bond. And, thus, if we count from left to right for example, OH will be on the first carbon.

    What do you think?
    The main functional group is the alkene not the alcohol so you look for the shortest route to the alkene functional group. Which is 3. therefore hex-3-ene. Taking this it leaves the hydorxy group on the 6th carbon and the methyl group on the 4th. There getting you 6-hydroxy,4-methyl,hex-3-ene
    Offline

    0
    ReputationRep:
    (Original post by SWEngineer)
    Why isn't it 1-hydroxy-3-methyl-3-hexene?

    Why are you inserting 6-hydroxy?

    Here, I think counting from either direction, left to right and vice versa gives the same as to the less number to reach the double bond. And, thus, if we count from left to right for example, OH will be on the first carbon.

    What do you think?
    Well spotted. Check the formula carefully and it is three carbons from either end to the START of the double bond. Figures: hexane has 5 C-C bonds, and this has the double bond in the centre so it is symmetrical with respect the to double bond and carbon chain. 1 hydroxy 3-methylhexa-3-ene is fine.

    To check, draw plain hex-3-ene and verify that it is the same counting from left to right or right to left on the same drawing.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 5, 2011
Poll
Favourite type of bread

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.