31281-40-0Relevant academic research and scientific papers
A reliable Pd-mediated hydrogenolytic deprotection of BOM group of uridine ureido nitrogen
Aleiwi, Bilal A.,Kurosu, Michio
, p. 3758 - 3762 (2012)
The benzyloxymethyl (BOM) group has been utilized widely in syntheses of a variety of natural and non-natural products. The BOM group is also one of few choices to protect uridine ureido nitrogen. However, hydrogenolytic cleavage of the BOM group of uridine derivatives has been unreliably performed via heterogeneous conditions using Pd catalysts. One of the undesirable by-products formed by Pd-mediated hydrogenation conditions is the over-reduced product in which the C5-C6 double bond of the uracil moiety was saturated. To date, we have generated a wide range of uridine-containing antibacterial agents, where the BOM group has been utilized in their syntheses. In screening of deprotection conditions of the BOM group of uridine ureido nitrogen under Pd-mediated hydrogenation conditions, we realized that the addition of water to the iPrOH-based hydrogenation conditions can suppress the formation of over-reduced uridine derivatives and the addition of HCO2H (0.5%) dramatically improve the reaction rate. An optimized hydrogenation condition described here can be applicable to the BOM-deprotections of a wide range of uridine derivatives.
Photochemical generation and reactivity of the 5,6-dihydrouridin-6-yl radical
Newman, Cory A.,Resendiz, Marino J. E.,Sczepanski, Jonathan T.,Greenberg, Marc M.
experimental part, p. 7007 - 7012 (2009/12/24)
(Chemical Equation Presented) Nucleobase radicals are the major family of reactive intermediates formed when nucleic acids are exposed to hydroxyl radical, which is produced by γ-radiolysis and Fe·EDTA. Significant advances have been made in understanding the role of nucleobase radicals in oxidative DNA damage by independently generating these species from photochemical precursors. However, this approach has been used much less frequently to study RNA molecules. Norrish type I photocleavage of the tert-butyl ketone (2b) enabled studying the reactivity of 5′-benzoyl-5,6- dihydrouridin-6-yl (1b). High mass balances were observed under aerobic or anaerobic conditions, and O2 did not affect the photochemical conversion of the ketone (2b) to 1b. Competition studies with O2 indicate that the radical abstracts hydrogen atoms from β-mercaptoethanol with a bimolecular rate constant = 2.6 ± 0.5 × 106 M-1s-1. The major product formed in the presence of O 2 was 5′-benzoyl-6-hydroxy-5,6-dihydrouridine (6). In contrast, 5-benzoyl-ribonolactone (7), a hypothetical product resulting from C1′-hydrogen atom abstraction by the peroxyl radical, could not be detected. Overall, tert-butyl ketone 2b is a clean source of 5′-benzoyl-5,6-dihydrouridin-6-yl (1b) and should prove useful for studying the reactivity of the respective radical in RNA.
