Abstract: A new and efficient synthetic route to malonamides and malonamic acid esters is described. S-tert-Butyl acetothioacetate monoanion reacted with aryl or alkyl isocyanates to give tricarbonyl compounds, which spontaneously deacetylated to the corresponding b-amidothioesters. Treatment of the latter with aliphatic or aromatic amines or alcohols at room temperature in the presence of silver trifluoroacetate provided malonamides or malonamic acid esters, respectively, in excellent overall yields.