Question

R..N /--OH NH2 NH Ho- O O' 、OH S O no HN O O S 2 H HN

On one hand, all compounds (nutrients, vitamins, drugs) consumed by humans must be soluble enough to enter our system but, on the other hand, not so soluble as to be filtered out by our kidneys before they can be effectively used. The above structures of penicillin and derivatives of penicillin highlight the difficulties in developing and administering drugs. All of the drugs in the penicillin family have the same mode of action; they all inhibit the formation of bacterial cell walls by inactivating an enzyme that supports the formation of cell walls. Ultimately, the weakened cell wall causes the bacterium to die. Unfortunately, the drugs cannot be administered by the same route due to differences in their solubility.

The four compounds above are members of the penicillin family. The structures of Penicillin and its derivatives highlight the difficulties in developing and administering drugs. Penicillin and Penicillin-G (1^st and 2^nd generation drugs, respectively) are the most effective at binding to and killing bacteria but neither can be administered by mouth. Ampicillin, a 3^rd generation drug, is partially effective orally but works better if injected. Amoxicillin, a 4^th generation drug, has proved to be orally effective.

In water Penicillin is the least soluble of the 4 compounds, Penicillin-G is also poorly soluble in water but better than Penicillin. Ampicillin is much more soluble in water than either of the Penicillin's but not as soluble as Amoxicillin.

A. Study the 4 structures and decide which, based on their solubility, is Penicillin, Penicillin-G, Ampicillin, or Amoxicillin and then write their names under the appropriate structure.

B. Why is amoxicillin effective orally while penicillin is not?

C. a) What functional groups were inserted or added to the penicillin-G structure to create a compound that could be administered by mouth (amoxicillin)?

b) Why – using chemical terms for bonding interactions – did they make those changes?

D. What feature common to all of the structures makes part of the molecule strained, and therefore, reactive? Explain.

Answer 1

2 nici lln Penicillin NH2 NH 시 moxyllin

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