Versatile synthesis of malonamic acid derivatives from a β-ketothioester

An efficient synthetic route is described that allows the preparation under mild conditions of several types of malonamic acid derivatives. The S-tert-butyl acetothioacetate monoanion reacted with aryl or alkyl isocyanates to give β-amidothioesters in one step and 73–87% yield, after spontaneous deacetylation of tricarbonyl intermediates. Treatment of these thioesters with several aliphatic or aromatic alcohols and amines at room temperature in THF or DME and in the presence of silver trifluoroacetate provided, respectively, the corresponding malonamic acid esters and malonamides in 80–100% yield.