PHENYLGLYCIDYL ETHER ADDUCTS OF 2'-DEOXYCYTIDINE AND 2'-DEOXYADENOSINE - STABILITY IN SOLUTION AND STRUCTURE-ANALYSIS BY ELECTROSPRAY TANDEM MASS-SPECTROMETRY

The adducts of phenylglycidyl ether with 2'-deoxyadenosine (dAdo) and 2'-deoxycytidine (dCyd) exhibit structural modifications. The N-1 addu ct of dAdo underwent rearrangement to the N-6 adduct; the N-3 adduct o f dCyd was deaminated to the corresponding 2'-deoxyuridine adduct. The se structural modifications were studied by using liquid chromatograph y-electrospray tandem mass spectrometry, and kinetic data for both rea ctions are presented. The low energy (+) collision-activated dissociat ion spectra of:the dAdo adducts allow the two positional isomers N-1 v ersus N-6 to be distinguished. The structure of the latter is independ ently proven by an extended NMR study. For the dCyd and 2'-deoxyuridin e adducts, information about the alkylation site is found in the colli sion-activated dissociation spectra. These spectra show the presence o f an unexpected N-di-alkylated dCyd in addition to the two epimeric N- 3 adducts.