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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

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

Grade:12

1 Answers

ruchi yadav
askIITians Faculty 27 Points
10 years ago
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 Nomenclature

1.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

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