Rakipov I. Fragmentation of RGD-peptidomimetics, containing b-alanine residue, in fast atom bombardment mass spectrometry

Thesis for candidate degree in chemistry, specialty 02.00.03 - organic chemistry. - A.V. Bogatsky Physico-Chemical Institute of NAS of Ukraine. Odessa, 2012.Thesis is dedicated to the study of RGD-peptidomimetics structure which contain b-alanine fragment by fast atom bombardment mass spectrometry (FAB MS). Systematic study FAB mass spectra of positive and negative ions are permitted to determine main fragmentation pathways investigated compounds and its analytical features. The relative probability of realization one or another fragmentation pathway is dependent on the charge location and stability of products formation, due to the structure and confirmed by quantum-chemical calculations. In case of hydrochlorides of investigated compounds which contain R=H, Ph, Hal-Ph in b-position of b-alanine, fragmentation of protonated [M+H]+ molecules leads to the formation b, y, у1 и b1 ions. Introduction of Alk-О-Ph substituent into the b-position of b-alanine promotes the appearance of new fragmentation pathways leads to formation с and z ions. Investigation of protonated RGD-peptidomimetics molecules by the tandem MS methods show, that formation of rearrangement [b1+OH+H]+ ions is depends not only on the substituent in b-position of b-alanine, but also on the central fragment of peptidomimetic structures. For isophthalic acid derivatives that rearrangement is dominated (except compound R=H), while other fragmentation pathways is not realized. Metastable product ions spectra of alkali metal-cationized molecules are characterized the intensive peak [b1+OH+Cat]+ ions while other characteristic ions for protonated molecules are absent. In case of compounds, which consist tert-Butyl carbamate group charge-remote fragmentation was dedicated.