Crack Antibiotics by Yourself
Now, many people come to me and say: "Look: I had school sores, so, I took oral dicloxacillin. Now, however, I suffer from a mild urinary tract infection, for which my doctor has prescribed me cephaloxin. But I still have a lot of dicloxacillin which I wouldn't like to throw away, wasting money! What can I do?!"
Actually, that's a lie: fortunately, no one has ever asked me such a stupid thing and now, I believe, this'll never happen, because, today, I'm going to prove how simple it is to crack antibiotics by yourself!
All you need are some banal items, you could find in every, decent, supermarket. For example, a certain quantity of 3-chloroperoxybenzoic acid is required, as you can see, right at the beginning, in order to oxidize the protected penicillin.
But, hey: can you imagine a supermarket that doesn't sell MCPBA?
Whenever I look at this reaction, Strauss' Blue Danube Waltz notes pop in my head. That's likely to be a direct consequence of my love for "2001:A space Odyssey": so, that acetate ion, which plays the key role in Morin rearrangement, always reminds me of a space shuttle, harmoniously floating.
By the way, given that the most complicated part of the job is already done, almost automatically, by the aforementioned rearrangement, the rest of the synthesis looks a little bit boring.
Triethylamine is added to yield the double bond.
You, then, remove the amide and the protecting group of the carboxylic function: what you get, in the end, is a close derivative of the original 7-aminocephalosporanic acid.
To increase the yield of the amide, the substituent that is added is modified so that the final step could go on smoothly: an anhydride eases the formation of the amide and the amine is efficiently protected in such a way that no interference might occur.
So, here you are: a penicillin turned into a cephalosporin through seven steps only.
Still, I believe it's not that cheaper, after all...
