New 3-hydroxy-1,5-benzodiazepin-2-ones were synthesized through condensation between ophenylenediamines with glycidic ester. Alkylation and oxidation of some of the obtained compounds were also explored in different conditions yielding various oxidized and alkylated benzodiazepines. The structural elucidation of the synthesized compounds was achieved by MS, NMR spectroscopy and also through X-ray diffraction analysis. The glycidic ester was thus shown to be an interesting synthon in the synthesis of new 1,5-benzodiazepines used in alkylation and oxidation reactions.

The fragmentation patterns of a series of three novel synthesized 3-hydroxy-4-phenyl-tetrahydro-1,5-benzodiazepin-2-ones (1-3), possessing the same backbone structure, were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) techniques. A simple methodology, based on the use of ESI (positive ion mode) and by increasing the declustering potential in the atmospheric pressure/vacuum interface, collision-induced dissociation (CID), was used to enhance the formation of the fragment ions. In general, the novel synthetic 1,5-benzodiazepine derivatives afforded, in the gas phase, both protonated and sodiated molecules. This led to the confirmation of the molecular masses and chemical structures of the studied compounds. Exact accurate masses were measured using a high-resolution ESI-quadrupole orthogonal time-of-flight (QqToF)-MS/MS hybrid mass spectrometer instrument. The breakdown routes of the protonated molecules were rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole-hexapole-quadrupole (QhQ) tandem mass spectrometer. All the observed major fragmentations for the 1,5-benzodiazepines occurred in the saturated seven-membered ring containing the nitrogen atoms. These formed a multitude of product ions by different breakdown routes. All the major fragmentations involved cleavages of the N-1-C-2 and C-3-C-4 bonds. These occurred with concomitant eliminations of glyoxal, benzene and ethyl formate, forming the product ion at m/z 119, which was observed in all the studied compounds. In addition, an unique simultaneous CID-MS/MS fragmentation was noticed for the 1,5-benzodiazepines 1 and 3, which occurred by a pathway dictated by the substituent located on the N-1-position. It was evident that the aromatic ring portion of the 1,5-benzodiazepines was resistant to CID-MS/MS fragmentation. Re-confirmation of the various geneses of the product ions was achieved by conducting a series of precursor ion scans. ESI-MS and CID-MS/MS analyses have thus proven to be a specific and very sensitive method for the structural identification of these novel 1,5-benzodiazepine derivatives.

Synthesis of New 1,5-Benzodiazepin-2-ones from Ethyl Glycidate. -The condensation of o-phenylenediamines (I) with substituted glycidate (II) to form diastereomeric benzodiazepinones (III) and (IV) is reported (no yields given). -(EL MESLOUHI, H.; ESSASSI, E. M.; ZERZOUF, A.; SALEM, M.; PETRUS, C.; VIALLEFONT, PH.; Bull.

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The structure of the title compound, C12H16N2O3, has been established by X‐ray crystallographic study. The dioxazocine ring has a chair conformation and a hydrogen bond links the O and N atoms of two adjacent carbamoyl groups.