Which is the correct base structure of Penicillin?

Adam_h

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 -

SW VandeCarr

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. .

Adam_h

Hi, thanks for your reply...
So in theory they are both correct, just another way of showing the same thing?

Adam

SW VandeCarr

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.

http://www.worldofmolecules.com/drugs/penicillin.htm

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.

http://www.biology.ed.ac.uk/research...s/penicill.htm

Adam_h

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
Adam

SW VandeCarr

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.