Attempts were then made to convert the thus-obtained e~ ters cis-VIII, cis-X, and cis-XI to the corresponding 2-substituted maleinimides. One route in this direction could consist in hydrolysis of the above esters to the corresponding maleic acids and transformation of these aCids to imides analogOusly to the synthesis of showdomycin2• This route failed in our case because of the great stability of the nitrile function in alkaline media.(As it has been fourid ...
