Mass spectrometric studies—II: Mass spectrometric studies of maleimides and benzaldazine adducts. Identification of solid mixtues

It has been found by mass spectrometric studies that the so‐called ‘1:1‐adduct’ formed by N‐( n butyl)maleimide and benzaldazine, is in fact a solid mixture of one part bis ‐imide L and one part benzaldazine. Bis ‐imide L is one of the three stereoisomeric products obtained by the addition of two mole of N‐( n ‐butyl)malemide and one mole of benzaldazine. The three stereoisomeric bis ‐imides gave identical mass spectra. Mass spectra of bis ‐imide M and bis ‐imide M‐ d 2 are discussed, and confirm the proposed structures of perhydroprazolo‐pyrazole derivatives for these 1:2‐adducts.