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I am having trouble with this homework problem.
Br
l
CH3CH2CHCH2CH2CH2OH
In case this doesn't line up right the Br is above the 3rd C.
What is this? |
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| | From:  ·Steve· | Sent: 4/12/2008 4:19 AM |
Br
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CH3–CH2–CH–CH2–CH2–CH2–OH 6 5 4 3 2 1 The OH group tells us this is an alcohol. Therefore, number the carbons starting from the end closest to the OH group. The six carbon alkane is hexane, which will be changed to the alcohol name by dropping "e" and adding "ol" giving "hexanol." Since the OH group is attached to carbon #1, this is 1-hexanol. Lastly, prefix this name with the names of the other groups attached to the main chain, in alphabetical order with their positions given. In this case there is only one group (we still call the bromine atom a "group") called the bromo group, attached to carbon #4. Therefore the complete name is 4-bromo-1-hexanol. Steve |
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Thank you. The way you numbered, really helps it to sink in..
"·Steve·" <[email protected]> wrote: <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Structural compounds
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| | | From: ·Steve· |
Br
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CH3–CH2–CH–CH2–CH2–CH2–OH 6 5
4 3 2 1 The OH group tells us this is an alcohol. Therefore, number the carbons starting from the end closest to the OH group. The six carbon alkane is hexane, which will be changed to the alcohol name by dropping "e" and adding "ol" giving "hexanol." Since the OH group is attached to carbon #1, this is 1-hexanol. Lastly, prefix this name with the names of the other groups attached to the main chain, in alphabetical order with their positions given. In this case there is only one group (we still call the bromine atom a "group") called the bromo group, attached to carbon #4. Therefore the complete name is 4-bromo-1-hexanol. Steve | |
View other groups in this category.
Meri Salcedo
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| | | From: ·Steve· | Sent: 4/12/2008 5:29 PM |
I tell my students to number the carbons literally as I did this time. Doing so helps prevent careless errors with the positions of the groups and the number of carbons in the main chain. Also, it is sometimes necessary to redraw the structure to make it easier to tell what's connected to what. A condensed formula written as follows is correct, but confusing: CH3CH(CH3)CH(CH3)CH2C(CH2CH3)2CH2CH2C(CH3)3 Here it is again, drawn more sensibly: CH3 CH2CH3 CH3 | | | CH3–CH–CH–CH2–C–CH2–CH2–C–CH3 | | | CH3 CH2CH3 CH3 9 8 7 6 5 4 3 2 1 Now it is much easier to name.  Steve |
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| | (1 recommendation so far) | Message 5 of 7 in Discussion |
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What if there is a structural compound like:
CH3
l In case it doesn't come out, the top C is over
CH3CCH3 the second C, and the bottom C is under the
l second C. How would you number this is order
CH2OH to get what it is?
Meri Salcedo
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| | | From: ·Steve· | Sent: 4/14/2008 5:17 PM |
You still want to find the longest carbon chain. Since this is an alcohol, this main chain should include the OH-bearing carbon. The easiest is just number them 1, 2, and 3 starting from the OH carbon and going up. But carbon #3 can also be either of the two methyl groups that are attached to the middle carbon because you will get the same result (exactly the same name). I'll highlight the three numbering possibilities: CH3
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CH3�?FONT color=#ff0066>C–CH3
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CH2–OH CH3
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CH3�?/FONT>C–CH3
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CH2–OH CH3
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CH3�?FONT color=#ff0033>C�?/FONT>CH3
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CH2–OH This is named 2,2-dimethyl-1-propanol. Steve |
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Steve,
Thanks again. It makes perfectly good sense to see it laid out like you did.
Thanks!!
Meri Salcedo
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