Abstract Mono-S-trimethylsilylketene dithioacetals have been prepared from dithioesters by the action of trimethylsilyl iodide formed in situ. They were reacted easily with dialkylazodicarboxylates to give good yields of α-hydrazinodithioesters. The latter were transformed into thioamides or endothiodipeptides by aminolysis either with an amine or an amino acid.