Organic Chemistry | 96102 - what will be the numbering order in n-askIITians

pogula sumanth Grade: 12

        what will be the numbering order in nomenclature for a compound that contain a substituent on a carbon and another carbon contain two substituents on it .

for exmple write the IUPAC name of following compound
                O CH3
                ||  |
CH3-CH-C-C -CH3
           |        | 
        CH3  CH3

6 years ago

Answers : (1)

ruchi yadav

askIITians Faculty

26 Points

							Please see the below example :(CH₃)₂CHCH₂CH(C₂H₅)C(CH₃)₃
This example illustrates some sub-rules of the IUPAC system that must be used in complex cases. The expanded and line formulas are shown below.
Sub-Rules for IUPAC Nomenclature1.If there are two or more longest chains of equal length, the one having the largest number of substituents is chosen.
2.If both ends of the root chain have equidistant substituents:
    (i) begin numbering at the end nearest a third substituent, if one is present.
    (ii) begin numbering at the end nearest the first cited group (alphabetical order).
In this case several six-carbon chains can be identified. Some (colored blue) are identical in that they have the same number, kind and location of substituents. The IUPAC name derived from these chains will not change. Some (colored magenta) differ in the number, kind and location of substituents, and will result in a different name. From rule 1 above the blue chain is chosen, and it will be numbered from the right hand end by application of rule (i). Remembering the alphabetical priority, we assign the following IUPAC name:3-ethyl-2,2,5-trimethylhexane.

Thank You
Ruchi
Askiitians Faculty