STUDY OF NEW SULFONYLUREAS BY MASS-SPECTR OMETRY

A series of new biologically active sulfonylurea were characterized by mass spectrometry. The substituents of the sulfonylurea group were ph enyl, norbornene, pyridine or pyrimidine rings. The high thermolabilit y of these molecules involves the use of two different ionizing method s: electron-impact (EI) and liquid secondary ion mass spectrometry (LS IMS). EI led to mass spectra depending on the probe and the source tem peratures, and was unable to indicate the true molecular mass. LSIMS g ave stable protonated or cationized molecules leading to this informat ion. Nevertheless, EI spectra indicated the nature of the two main pre cursors of the skeleton: isocyanate and sulfonamide. The information g iven by the two complementary ionization modes led to the characteriza tion of the molecules, in spite of their high thermolability and their low volatility.