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Author: Subject: Molecular model: what type of bond is this?
jwarr
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[*] posted on 3-7-2009 at 09:04
Molecular model: what type of bond is this?


I was perusing wikipedia and found myself looking at the following:


I haven't taken any organic chemistry yet, which I assume is the problem. Could someone please tell me what that squiggly bond signifies?
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Sauron
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[*] posted on 3-7-2009 at 09:13


It just means that is an attachment point for an unspecified ligans or group and of unspecified stereochemistry.



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TheOrbit
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[*] posted on 3-7-2009 at 10:47



you should give the link to the problem you ask for.

[Edited on 4-7-2009 by TheOrbit]
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JohnWW
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[*] posted on 3-7-2009 at 13:08


That means phenylethylamine derivatives - amphetamine, including methamphetamine! BTW Any attachments other than H to the point of attachment of those unspecified groups, the carbon alpha to the NH2 group or beta to the C6H5 group, would result in that carbon becoming asymmetric and optically active.
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UnintentionalChaos
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[*] posted on 3-7-2009 at 15:32


That line indicates unspecified stereochemistry. It's not showing an unknown group, but rather a methyl group. The file is from here, by the way:

http://en.wikipedia.org/wiki/File:Amphetamine-2D-skeletal.sv...

:P

An unknown group is either represented with an "R" (or an X in the case of an unspecified halogen) like this:



Sometimes, you also see this as well, which is probably what Sauron is thinking about :



In this case, the goal is usually not to indicate that there is an unknown substituent on some core structure, but rather to focus on the specified structure; in this example, the acetyl moiety.

[Edited on 7-3-09 by UnintentionalChaos]




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Siddy
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[*] posted on 3-7-2009 at 17:08


When you learn stereochemistry you will see that when you have a carbon (sp2) with 4 different substitutes (bonded to 4 different things, in this case a H, Benzy, amine and methyl), the specific arrangement can change the compound. This is a type of isomer (you have probably already touched on some types of isomers).Its hard to visualize without physical models.

But what that squiggly line means, is that the bond SHOULD be specified as going INTO or OUTOF the page (designating specific sterochemistry), but for the purpose of just showing amphetamine they dont care (i think because both isomers are active). In all my chem classes and text books i have never come across squiggly lines and you should use them unless ur lecturer does. Its kind of a cop out and you will be asked to draw specific isomers even in basic chem classes so dont worry about them.
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12AX7
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[*] posted on 3-7-2009 at 20:27


I haven't seen the "bond-tilde" notation before. Unspecified groups are usually written as R groups.

The wavey bond does indeed mean it can be R or S.

Another unspecified bond you might see is a line going to the center of a phenyl ring. This means the group may be substituted on any arbitrary point around the ring, or it may be a mixture (usually with some preference, para/ortho or meta).

Tim

[Edited on 7-4-2009 by 12AX7]




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