Efficient
radiotherapy requires the concomitant use of ionizing
radiation (IR) and a radiosensitizer. In the present work uracil-5-yl
O
-sulfamate (SU) is tested against its radiosensitizing
potential. The compound possesses appropriate dissociative electron
attachment (DEA) characteristics calculated at the M06-2X/6-31++G(d,p)
level. Crossed electron–molecular beam experiments in the gas
phase demonstrate that SU undergoes efficient DEA processes, and the
single C–O or S–O bond dissociations account for the
majority of fragments induced by electron attachment. Most DEAs proceed
already for electrons with kinetic energies of ∼0 eV, which
is supported by the exothermic thresholds calculated at the M06-2X/aug-cc-pVTZ
level. However, in water solution under reductive conditions and physiological
pH, SU does not undergo radiolysis, which demonstrates the crucial
influence of aqueous environment on the radiosensitizing properties
of modified nucleosides.