Prodrugs of aza nucleosides based on proton transfer reaction
DFT calculation results for intramolecular proton transfer reactions in Kirby's enzyme models 1-7 reveal that the reaction rate is quite responsive to geometric disposition, especially to distance between the two reactive centers, r (GM), and the angle of attack, alpha (the hydrogen bonding angle). Hence, the study on the systems reported herein could provide a good basis for designing aza nucleoside prodrug systems that are less hydrophilic than their parental drugs and can be used, in different dosage forms, to release the parent drug in a controlled manner. For example, based on the calculated log EM, the cleavage process for prodrug 1ProD is predicted to be about 10(10) times faster than that for prodrug 7ProD and about 10(4) times faster than prodrug 3ProD: rate (1ProD) > rate (3ProD) > rate (7ProD) . Hence, the rate by which the prodrug releases the aza nucleoside drug can be determined according to the structural features of the linker (Kirby's enzyme model).
proton transfer reaction dft calculations kirby's enzyme model aza nucleosides prodrugs decitabine prodrugs effective molarity (em)