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Medical Which is the correct base structure of Penicillin?

  1. Aug 3, 2010 #1
    Hi, I have done quite a bit of looking about and i'm aware that there are many forms of penicillin...
    While looking at the base structure of penicillin i have found two different kinds... At a guess i'd say one is synthetic and one is natural form?

    Could someone possibly clear this up for me? Thanks in advance for any help you can provide.
    Here are the two pictures of the chem structures, i need to know which is the main base for Pen...

    Number 1 -

    Number 2 -
  2. jcsd
  3. Aug 3, 2010 #2
    The second shows the proper relation (according to my source) of the R group to the lactam ring but otherwise lacks the detail of the first. .
    Last edited: Aug 3, 2010
  4. Aug 4, 2010 #3
    Hi, thanks for your reply...
    So in theory they are both correct, just another way of showing the same thing?

  5. Aug 4, 2010 #4
    No. I edited by last post. The second one is correct according to several sources. The first lacks an oxygen double bond just after the R group attachment.


    Always check what is actually posted rather than what shows in your email. It seems that the first diagram is defining the R group a bit differently, but not all R groups have the -CONH- chain.

    Last edited: Aug 4, 2010
  6. Aug 4, 2010 #5
    Hi, I did actually check on the forum... No worries though.

    So it still is number 1 still penicillin? just part of another strand of penicillin?

    Thanks again
  7. Aug 4, 2010 #6
    Diagram number one has the core beta lactam structure according to my second link. However, most diagrams of PCN include the double bond O next to the R attachment (see link one). If you remove the R-O-, and substitute a hydrogen you get penicillanic acid.
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