ESI-MS spectra of 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones

Twelve 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones were investigated by tandem mass spectrometry using positive as well as negative electrospray ionization. The influence of the electron affinity of the substituent and the steric effect on the fragmentation is discussed. Pyridinones with a substituent of low proton affinity show loss of water, HCN or benzene from the pyridinone ring in the first step of MS2 fragmentations. Oppositely, if a substituent with high proton affinity is present on the phenyl ring in the 4-position of pyridinone, the fragmentation paths are complex, depending mainly on the substituent proton acceptor ability. Elimination of neutral molecules CO, HCN, H2O, PhH (benzene) or Ph and CN radicals are fragmentation processes common for all compounds in the subsequent steps of the fragmentations. 3-Cijano-4-(supstituisani fenil)-6-fenil-2(1H)-piridinoni su ispitivani tandem masenom spektrometrijom koriscenjem pozitivne i negativne elektrosprej jonizacije. Ispitivan je uticaj supstituenata i sternog efekta na fragmentacije. Piridinoni koji imaju supstituente malog afiniteta prema protonu pokazuju gubitak vode, HCN ili benzena iz piridinonskog prstena u prvom koraku MS2 fragmentacija. Suprotno, ako je supstituent sa visokim afinitetom prema protonu prisutan na fenilnom prstenu u 4-polozaju piridinona, slozeni fragmentacioni putevi uglavnom zavise od jacine te interakcije. Eliminacije neutralnih molekula CO, HCN, H2O, PhH (benzen) ili Ph i CN radikala su fragmentacioni procesi uobicajeni za sva ispitivana jedinjenja u narednim fragmentacionim stupnjevima.