An expedient synthesis of 3-acyltetramic acids of the melophlin family from α-aminoesters and immobilized Ph3PCCO

The naturally occurring 3-acyltetramic acids (3-acylpyrrolidine-2,4-diones) melophlin A, B, C and G were prepared in few steps from α-aminoesters or their hydrochlorides by cyclization with Ph3PCCO under mild conditions. The employment of immobilized, polystyrene-bound ylide greatly simplifies the removal of by-product Ph3PO and of other impurities. Various 3-acylation methods were assessed.