Radical fragmentation-phosphorylation

The one-pot radical fragmentation-phosphorylation reaction of a-amino acids or 3-amino alcohols (e.g., 619) affords a-amino phosphonates 620 in good yields (Scheme 3.243). This reaction has been applied to the synthesis of biologically active phosphonates [651]. 

The reaction of dimethyl phosphite with tetrafluoroethylene in a sealed tube in the presence of a free radical initiator (/-BujOj, Bz O, AIBN) leads to a mixture from which the major product, dimethyl 1,1,2,2-tetrafluoroethylphosphonate, is isolated in 48% yield.In 1996, the radical addition of a phosphoryl fragment to difluoroalkenes to produce the corresponding difluoroalkyl-phosphonates was described independently by two groups (Scheme The phosphoryl... 

The pathway B begins as the pathway A, but the C4 radical 6 breaks the secondary C-0 bond of the phosphate linkage at the 3 position in a hetero-lytic reaction. This releases a 5 -phosphorylated DNA fragment and a radical cation 14. This radical cation reacts with H2O to generate a new 4 -DNA radical 15, which forms a hydroperoxide 16 by reaction with O2. Then the... 

ROS and RON can react with the DNA molecule and induce purine or p)u imidine base or sugar lesions, nitration and deaminations of purines, and DNA-DNA or DNA-protein cross-links (Dizdaroglu et al., 2002). These processes lead to mutations and impaired transcriptional and posttranscriptional processes and compromise protein synthesis (Colurso et al., 2003). In addition, DNA damage, oxidative phosphorylation, and altered cell metabolism may lead to apoptosis and promote neuronal death (Fishel et al., 2007 Becker and Bonni, 2004). ROS and RNS can also attack amino acids, leading to the formation of carbonyl derivatives (Stadtman and Levine, 2003). Oxidation of protein also leads to protein fragmentation and protein cross-linking. In addition, peroxynitrite and a hydroxyl radical can react with tyrosine and form other indexes of protein oxidation,... 

Phosphoryl-fullerenyl radicals that have an q -coordinated [ML2] fragment have been prepared. The complex [Pd (-h)-diop)(q -C6o)] has been shown to undergo M-C bond rupture as a consequence of phosphoryl radical attack at the metal centre. Evidence was shown for the coordination of benzene in an q -fashion prior to C-H activation at a Pt(II) centre the process is reversible. [I(py)2]N03 has been shown to oxidatively add to [Pt(N-N)(q -alkene)]. 

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