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    CH3CH(Br)2CH2CH2CH2CH(Cl)2CH(Cl) 2?
    Is this 2,2-dibromo-6,6,7,7-tetrafluoroheptane? Should one follow the alphabetical rule first here(smallest number for bromine) or the lowest sum rule (smallest chlorine number?
    Also, what would CH3CH(CH3)2CH(CH2CH3)C(TRIPLE BOND)C-CH2-CH(F)CH3 be? 2 fluoro 6 ethyl 7,7 dimethyloctyne?
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    I agree with the IUPAC name you have given to the first molecule, but for the second one, are you sure you have written the formula correctly as I don't see how there are five bonds on the second carbon atom??
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    Neither.

    http://www.chem.ucalgary.ca/courses/...ifference.html

    If that doesn't answer your questions, please come back to me.
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    (Original post by JustThatStudent)
    I agree with the IUPAC name you have given to the first molecule, but for the second one, are you sure you have written the formula correctly as I don't see how there are five bonds on the second carbon atom??
    Sorry it's meant to be C only
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    (Original post by Pigster)
    Neither.

    http://www.chem.ucalgary.ca/courses/...ifference.html

    If that doesn't answer your questions, please come back to me.
    • the principal functional group is given the lowest possible locant
    • substituents are then assigned locants based on this numbering scheme in such a way as to give the lowest locant number at the first time there is a difference
    • in the event that there is no first point of difference in the locants, substituents are numbered based on alphabetisation giving the first substituent the lowest possible locant number

    Thank you for sharing such a useful resource With regard to the first bullet point, how does one decide what the principal functional group is, let's say is a compound contains -CO- and a halogen as well as NH2 etc? Which would get priority?
    Also, the second bullet point; what does it mean in general terms? What is the 'point of difference' it constantly mentions?
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    For the second molecule I think it should be either:

    3-ethyl-2,2-dimethyl-7-fluorooct-4-yne

    Or

    3-ethyl-2,2-dimethyl-7-fluoro-4-octyne

    I would think that the ethyl functional group comes first as it is first alphabetically, but the numbering must be based on the position of the triple bond group, and you should also number this as there are several places the triple bond could appear, as opposed to propene, for example.

    What do you think of this?
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    (Original post by BackLumbarJack)
    • the principal functional group is given the lowest possible locant
    • substituents are then assigned locants based on this numbering scheme in such a way as to give the lowest locant number at the first time there is a difference
    • in the event that there is no first point of difference in the locants, substituents are numbered based on alphabetisation giving the first substituent the lowest possible locant number

    Thank you for sharing such a useful resource With regard to the first bullet point, how does one decide what the principal functional group is, let's say is a compound contains -CO- and a halogen as well as NH2 etc? Which would get priority?
    Also, the second bullet point; what does it mean in general terms? What is the 'point of difference' it constantly mentions?
    You kind of have to learn the priorities, because they change depending on which functional groups are present.
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    (Original post by BackLumbarJack)
    how does one decide what the principal functional group is
    http://www.masterorganicchemistry.co...-nomenclature/
 
 
 
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