The photochemical reactivity and photophysical and electrochemical properties of a series of N-adamantylphthalimides bearing carboxylic functional groups were investigated. Upon irradiation (with or without a triplet sensitizer), the compounds undergo decarboxylation via photoinduced electron transfer (PET) from the carboxylate to the phthalimide. UV-vis and fluorescence pH titrations were used to determine pK_a values for the prototropic forms, which were put in connection with the quantum yields of the reaction (Φ_R). The compounds bearing electron donors OH and OCH₃ at the phthalimide 4 position are fluorescent (Φ_F = 0.02–0.49) and PET takes place from both singlet and triplet excited states. The estimated rate constants for PET in the singlet excited states for the methoxy- and amino-substituted phthalimides are (2.0 ± 0.1) × 10⁹ s⁻¹ and (3.4 ± 1.0) × 10⁷ s⁻¹, respectively. Laser flash photolysis (LFP) was conducted to characterize the triplet excited states, which are populated less efficiently for compounds with electron donors. The PET is reversible and the overall Φ_R depends on the rates for back electron transfer, protonation of the phthalimide radical anion and decarboxylation. The plausible photochemical and photophysical pathways depend on the phthalimide substituents, which is important for the use of phthalimide derivatives in organic synthesis and photocatalysis.

Rosuvastatin, a member of the statin family of drugs, is used to regulate high cholesterol levels in the human body. Moreover, rosuvastatin and other statins demonstrate a protective role against free radical-induced oxidative stress. Our research aimed to investigate the end-products of free radical-induced degradation of rosuvastatin. To induce the radical degradation, an aqueous solution of rosuvastatin was irradiated using different doses of gamma radiation (50–1000 Gy) under oxidative conditions. Rosuvastatin and related degradation products were separated on nanoC18 column under gradient elution, and identification was carried out on hyphenated nanoUPLC and nanoESI-QTOF mass spectrometer system. Elemental composition analysis using highly accurate mass measurements together with isotope fitting algorithm identified nine major degradation products. This is the first study of gamma radiation-induced degradation of rosuvastatin, where chemical structures, MS/MS fragmentation pathways and formation mechanisms of the resulting degradation products are detailly described. The presented results contribute to the understanding of the degradation pathway of rosuvastatin and possibly other statins under gamma radiation conditions.