Ethyl N-bromo-alkylcarbamates as heterocyclic precursors and extractives from Oceanapia sp.
The synthesis of p-lactams has been of foremost importance since the discovery of penicillin by Sir Alexander Fleming, in 1928, and its susequent structure elucidation in 1945. Ethyl N-2-bromo-alkylcarbamates show considerable potential as precursors to p- lactams. In the past, p-lactams have been prepared by many methods, none of which have involved 2-3 bond formation. The proposed ring closure using ethyl N-2-bromoalkylcarbamate involves 2-3 bond formation, making this method of synthesis novel. This work describes two attempted methods of cyclisation. The first using a Grignard reagent, and the second, using abstraction of an acidic proton a to a phosphonate group. These methods of intramolecular cyclisation were based on analogous intermolecular additions, which are also described. The second method was also used to determine the general potential of ethyl N-bromo- alkylcarbamtes as precursors to other heterocyclic systems.