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Topic: Help finding mass fragment in organic compound  (Read 4026 times)

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Offline robert_l

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Help finding mass fragment in organic compound
« on: May 20, 2009, 05:10:51 AM »
What would be the fragment of this molecule (mass=165) with a m/z of 137, i.e. loss of 28?

Is this a McLafferty rearrangement? i don't think so because there is no aldehyde or ketone group, but not sure how to get a m/z of 137?

thank you in advance.
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Offline StarvinMarvin

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Re: Help finding mass fragment in organic compound
« Reply #1 on: May 20, 2009, 05:34:43 AM »
Most common leaving fragments weighing 28 are N2 and ethene. Do you see how this could work in your example? Do you know the ionization type? Did you try to work the mechanism out?
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Offline robert_l

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Re: Help finding mass fragment in organic compound
« Reply #2 on: May 20, 2009, 05:56:48 AM »
I tried doing the McLafferty rearrangement to produce a 6 membered ring, in which I have produced ethene but i'm not sure if my mechanism is correct. this is what i got:
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Offline StarvinMarvin

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Re: Help finding mass fragment in organic compound
« Reply #3 on: May 20, 2009, 06:38:44 AM »
Don't you think that one of the products has to have a charge?
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Offline robert_l

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Re: Help finding mass fragment in organic compound
« Reply #4 on: May 20, 2009, 06:43:26 AM »
The first product should have a positive charge on it. Also, I think there are spare electrons on the O atom.

thanks for your help.
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