Synthesis, Chemical Reactivity, and Cytotoxicity of 2-Bis(alkoxycarbonyl)methyliden-1-azabicyclo[3.1.0]hexane Systems Related to Antitumor Antibiotic Carzinophilin A
Synthesis of the model compounds of carzinophilin carrying 2-methylidene-1-aza-bicyclo[3.1.0]hexane systems was achieved. Formation of malonylidenes or N-acyl-glycinylidenepyrrolidines was carried out by utilizing Eschenmoser's sulfide contraction or Herdeis's condensation between the 2-methylthio-Δ1-pyrrolone derivatives and ethyl nitroacetate, respectively. The 1-azabicyclo-[3.1.0]hexane systems