Thermal Behavior and Characterization of Some 2-Oxazolidinone Derivatives

Abstract

Abstract Four kinds of 2-oxazolidinone derivatives, (1) [5-phenoxymethyl-3-phenylcarbamoyl-2-oxazolidinone (1a), 2,4-bis(2-oxo-3-oxazolidin-3-ylcarbonylamino)toluene (1b), N,N′-bis(2-oxo-3-oxazolidin-3-ylcarbonyl)-1,6-hexanediamine (1c), and 1,4-bis(3-phenylcarbamoyl-2-oxo-5-oxazolidin-5-ylmethoxy)benzene (1d)], were prepared with the addition of 2-oxazolidinone, 5-phenoxymethyl-2-oxazolidinone (2), and 1,4-bis(2-oxo-5-oxazolidin-5-ylmethoxy)benzene (3) to mono- or diisocyanates by using N,N-dimethylformamide or benzene as solvents and 1,4-diazabicyclo[2.2.2]octane as a catalyst. Compound 1 was found to be thermally stable by thermal analysis. DSC curves of these compounds revealed an endothermic peak due to melting, except for 1d which was obtained from 3. The main fragmentation mechanism by electron impact for 1 was found to consist of two processes: simple cleavage and a rearrangement reaction. Further, each process was followed by cleavage modes. The proportion of fragment ions containing the benzene ring in the main fragmentation was greater than 80%. From the DTA-TG/DTG curves, the difference between EI-cleavage and thermal decomposition for 1a was elucidated.