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Thread: question about chemical notation

  1. #1 question about chemical notation 
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    Please have a look at this diagram of 5-meo-dmt:



    Is there any reason why the terminal molecule on the upper right branch says H3C whereas the other molecules on the other branches say CH3? Does it matter in notation whether the H3 comes before or after the C?


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  3. #2  
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    It does not matter except to provide a slight amount of additional information that the Hydrogen atoms are evenly distributed. Generally it is more correct to have the hydrogens follow the carbon due to convention but in this case the desire to indicate symmetry overrode convention. It is common to indicate symmetry as was done.


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    Moderator Moderator AlexP's Avatar
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    cypress is correct. There is no difference between CH<sub>3</sub> and H<sub>3</sub>C -- they are both methyl groups. It is simply how the illustrator chose to represent the group. If it has 3 Hs and 1 C, it's a methyl group.

    A little side note... Sometimes you'll see a shorthand notation for alkyl groups, e.g. Me for methyl, Et for ethyl, etc. This would eliminate the need to redraw groups according to their position within a molecule, but the redrawing isn't a big deal anyway once you realize they're all the same thing.
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  5. #4  
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    Thanks both,

    Quote Originally Posted by cypress
    It is common to indicate symmetry as was done.
    So in what way is CH3 "asymetrical" (I have no knowledge of chemistry )?
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    It's not really. But many who write out the structural model of the dimethyl groups the way they did to indicate there is shape symmetry around the amine group even as you surmised it really can't be any other way. Why the interest in dimethyltrypamine? It is not to be trifled with.
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    Forum Professor Zwirko's Avatar
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    I would've thought that the most logical reason as to why the structure is drawn that way is simply to show that the carbon of the methyl group is the atom that is bonded to the nitrogen?
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  8. #7  
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    If it was written as CH<sub>3</sub> there's still no reason why you couldn't attach the line to the C.
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