LAUSR

Abstract Quinone derivatives are promising anticancer, antimalarial, and antileishmanial drug candidates. Lapachol is the main natural quinonoid compound studied to date. The synthesis of lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone) derivatives can help characterization of these compounds in biological matrixes or extracts, particularly by electrospray ionization tandem mass spectrometry (ESI–MS/MS). The synthesized 2-methoxy-, 2-tosyl- and 2-mesyl- derivatives were protonated and fragmented by collisional-induced dissociation (CID); their fragmentation mechanisms were proposed based on CID results and DFT calculations. Quantum Theory of Atoms-in-Molecules, QTAIM, was performed and the bond weakening/reinforcement from bond critical point analysis of electronic densities was used to suggest the fragmentation pathways. Results herein were compared to data previously reported for lapachol (2-hydroxy-1,4-naphthoquinone). The tosyl derivative underwent an interesting fragmentation mechanism, which was comparable to the mechanism undergone by protonated lapachol. Therefore, identifying these compounds by the product-ions produced during ESI–MS/MS spectrometry is feasible.