Synthetic studies towards the total synthesis of rigidiusculamide D: pyrrolidinones from ascomycetes fungus / Nur Syazwani Osman

The synthetic studies towards the total synthesis of rigidiusculamide D: pyrrolidinone from ascomycetes fungus employed convergent approach was divided into two parts. The first part which was the preparation of tetramic acid ring was then divided into several routes to produce four different compounds of tetramic acid ring. For the first route, methyl acetoacetate was used as the starting material which undergoes alkylation, bromination and intramolecular cyclization reaction which produced two different compounds which were monomethylated compound and dialkylated compound at C3-position of the tetjamic acid ring. For the second route, glycine methyl ester, ethyl bromoacetate and sarcosine were used as the starting material which produced unprotected, JV-benzylated and JV-methylated tetramic acid ring through alkylation, condensation and Dieckmann cyclization reaction. In the second part, benzofuran ring was synthesized using two different starting materials namely methyl 4-hydroxybenzoate and 4-hydroxybenzaldehyde. Both starting material undergo prenylation reaction, epoxidation and cyclization reaction in order to obtain the target molecules. Finally, after successfully synthesized both desired tetramic acid ring and benzofuran ring, coupling reaction or condensation reaction took place in order to obtain the key carbon skeleton towards the synthesis of rigidiusculamide D: pyrrolidinone.