Addition of one of the amide amines to the nitrile would then afford the iminonitrile 5. The observed product 6 can be rationalized by assuming loss of the carboxamide under strongly basic conditions. Decarboxylative hydrolysis of 6 then leads to bemegride 7.
Adding one of the amide amines to the nitrile would subsequently yield the iminonitrile 5. The observed product 6 can be explained by assuming the loss of the carboxamide under strongly alkaline conditions. Decarboxylative hydrolysis of 6 then results in bemegride 7.