Acetoxymaleic anhydride

Recognition that 23 is actually the anhydride of acetylene dicarboxylic acid (225) led to some early attempts and claims of cyclization of this molecule with various reagents. Using acetic anhydride, the product isolated was acetoxymaleic anhydride (226), postulated as possibly arising from the addition of acetic acid to 23. Pyrolysis of either 226 or of diacetyltartaric acid... 

Attempts to generate a related didehydrospecies, the anhydride of acetylene dicarboxylic acid (23), ended in failure, although the authors were sufficiently optimistic to reserve future studies in this area to themselves. A few years later the intermediacy of 23, along with the four-membered cycloalkyne 24, was claimed during the pyrolysis of acetoxymaleic acid anhydride. 

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