Fragmentation studies and electrospray ionization mass spectrometry of lapachol: protonated, deprotonated and cationized species

Author(s)

Vessecchi, Ricardo ^{[1, 2]} ; Emery, Flavio S. ^[3] ; Galembeck, Sergio E. ^[2] ; Lopes, Norberto P. ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Quim & Fis, BR-14040903 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Dept Quim, Fac Filosofia Ciencias & Letras Ribeirao Preto, BR-14040903 Ribeirao Preto, SP - Brazil

^[3] Univ Sao Paulo, Dept Ciencias Farmaceut, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: RAPID COMMUNICATIONS IN MASS SPECTROMETRY; v. 24, n. 14, p. 2101-2108, JUL 2010.
• Web of Science Citations: 27

Abstract

Electrospray ionization mass spectrometric analysis of lapachol (2-hydroxy-3-(3-methy1-2-butenyl)-1,4-naphthoquinone) was accomplished in order to elucidate the gas-phase dissociation reactions of this important biologically active natural product. The occurrence of protonated and cationized species in the positive mode and of deprotonated species in the negative mode was explored by means of collision-induced dissociation (CID) experiments. For the protonated molecule, the H(2)O and C(4)H(8) losses occur by two competitive channels. For the deprotonated molecule, the even-electron rule is not conserved, and the radicalar species are eliminated by formation of distonic anions. The fragmentation mechanism for each ion was suggested on the basis of computational thermochemistry. Atomic charges, relative energies, and frontier orbitals were employed aiming at a better understanding of the gas-phase reactivity of lapachol. Potential energy surfaces for fragmentation reactions were obtained by the B3LYP/6-31+G(d,p) model. Copyright (C) 2010 John Wiley \& Sons, Ltd. (AU)

• FAPESP's process: 05/01572-1 - The use of computational chemistry in chemical processes involved in electrospray ionization
• Grantee: Ricardo Vessecchi Lourenço
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/08281-3 - Gas-phase reactivity of quinonoid compounds lapachol derivatives by electrospray ionization: Synergism between computational and experimental methods
• Grantee: Ricardo Vessecchi Lourenço
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 09/14184-0 - Antiinfective compounds: bringing together medicinal chemistry and organic synthesis in search of lead antiparasitic compounds
• Grantee: Flavio da Silva Emery
• Support Opportunities: Regular Research Grants