Recently, pharmaceutical research has been focused on the design of new antibacterial drugs with higher selectivity towards several strains. Major issues concern the possibility to obtain com-pounds with fewer side effects, at the same time effectively overcoming the problem of antimi-crobial resistance. Several solutions include the synthesis of new pharmacophores starting from piperazine or morpholine core units. Mass spectrometry-based techniques offer important sup-port for the structural characterization of newly synthesized compounds to design safer and more effective drugs for various medical conditions. Here, two new piperazine derivatives and four new morpholine derivatives were synthesized and structurally characterized through a combined approach of FT-ICR and LTQ mass spectrometry. The support of both high-resolution and low-resolution mass spectrometric data namely accurate mass measurements, isotopic distribu-tion and MSn spectra, was crucial to confirm the success of the synthesis. These compounds were further evaluated for inhibitory activity against a total of twenty-nine Gram-positive and Gram-negative bacteria to determine the action spectrum and the antimicrobial effectiveness. Results demonstrated compounds’ antimicrobial activity against many tested bacterial species, providing an inhibitory effect linked to different chemical structure and suggesting that the new-synthesized derivatives could be considered as promising antimicrobial agents.

Dubermatinib (DMB, TP-0903), a benzenesulfonamide, is an inhibitor of the tyrosine kinase AXL, which is a member of the TAM family, and can prevent GAS6-mediated activation of AXL in cancer cells. Patients with previously treated chronic lymphocytic leukemia are being studied in phase I/II clinical trials to determine its antineoplastic potential (CLL). In the current work, the reactive intermediates of DMB were studied using liquid chromatography-mass spectrometry (LC-MS). Human liver microsomes (HLMs) were exposed to dimethylbenzene in a laboratory setting, and the resulting metabolites were collected through protein precipitation. Intense reactivity toward nucleophilic macromolecules was seen in the metabolites of the piperazine and pyrimidine rings in DMB, iminium and 2,5-quinone-imine, respectively. To assess the toxicities of the possibly reactive metabolites, DMB was incubated with HLMs in the presence of 1.0 mM KCN and 1.0 mM glutathione. The DMB metabolites found by LC-MS/MS were seven in vitro phase I metabolites, three cyano adducts, and two GSH conjugates. Phase I in vitro metabolic reactions included N-demethylation, hydroxylation, and dechlorination. The in vitro metabolism of DMB and the metabolites it produces have not been studied before.