Cyclopropenones. IV. The Reactions of Diphenylcyclopropenone with Water, Carboxylic Acid, Phenol, and Amide

The pyrolysis of diphenylcyclopropenone monohydrate (II) at 150°C afforded α-phenyl-trans-cinnamic anhydride (VI). It was proved that the reaction consists of two main steps, the nucleophilic attack of water on I to yield α-phenyl-trans-cinnamic acid (IV), and the reaction of I with IV, thus finally yielding VI. The same type of reaction as that of I with IV was also observed when I was heated in phenol to afford phenyl α-phenyl-trans-cinnamate (XII). The reaction of I with the weak nucleophilic reagent, α-phenyl-trans-cinnamamide (XIV), afforded a monoimino derivative of VI (XVI), which is believed to be produced by the nucleophilic attack of the amide-oxygen of XIV on the carbonyl-carbon of I.