Thermal Behavior and Mass Spectra of 5-Phenoxymethyl-2-oxazolidinones and 5-Phenyithiomethy1-2-oxazolidinone

Abstract

5-Phenoxymethy1-2-oxazolidinone(PM0), its derivatives, and 5-phenylthiomethy1-2-oxazo lidinone(PTO) were prepared by the reaction of tris(2, 3-epoxypropyl) isocyanurate with various phenols and benzenethiol. The oxazolidinones were found by the thermal analysis to be thermally stable. Both DTA and DSC curves for these compounds except for PMO revealed a single endothermic peak in the vicinity of their melting points. Heat of fusion had the lowest value for PTO. The heat of fusion values of compounds containing the electronreleasing substituents was greater than those of the electron-attracting substituents for PMO derivatives (Table 2). The main fragmentation mechanism by electron impact for the linkages between the benzene and oxazolidinone rings was found to consist of two processes; simple cleavage ( I ) and rearrangement reaction(II). Further, each process had the three cleavage modes (Fig.4). The ( I )/( II) ratios for the intensities of the main fragment ions in mass spectra were 0.52in PMO and 1.13 in PTO. The base peak for most PMO derivatives was RC₆H₅O(Degree of unsaturation =4.0). The proportion of fragment ions containing the benzene ring in the main fragmentation was greater than 80% (Table 4).