Studies on chemical alterations of nucleic acids and their components—VII

The Cascade Methylation/Cyclization of ortho‐Cyanoarylacrylamides with Dicumyl Peroxide

“…Based on the experimental results and the literatures,[4e], [8a], a plausible mechanism for the methylation/cyclization cascade is proposed in Scheme . The thermal homolytic cleavage of DCP generate the cumyloxyl radical, which underwent the β‐cleavage to afford the methyl radical and acetophenone.…”

“…Peroxides are commonly used as radical initiators and oxidants because homolysis of its O–O band could provide alkoxy or acyloxy radicals, which may undergo further β‐cleavage to generate the alkyl radical . Since the pioneering studies by Kawazoe and co‐workers, demonstrated a methylation of the protonated nucleobases by using tert ‐butyl hydroperoxide (TBHP) as the methylation reagent,[4a] a series of peroxides such as tert ‐butyl peroxybenzoate (TBPB), di‐ tert ‐butyl peroxide (DTBP), cumyl hydroperoxide (CHP), and dicumyl peroxide (DCP), have been successfully applied to the methylation of (hetero)arenes, alkenes, carboxylic acids/amides, sulfoximines, and isocyanides . Although these advances have been made, developing new methylation to construct valuable molecules is still desirable.…”

Ribonucleosides and Rna

“…However. only guanosine can be specifically modified at the 8-position ( Figure 13) (29). Adenosine resulted in modification at the 2-and 8-positions.…”

GMP and AMP as methyl radical traps in the reaction with pentaamminemethylcobalt(III)

“…Purines are known to undergo C8 methylation by reaction with a methyl radical [6][7][8]. The radical pathway for preparation of C-alkylated purines is in some cases sufficiently efficient to be utilized for preparative purposes [5].…”

“…The radical pathway for preparation of C-alkylated purines is in some cases sufficiently efficient to be utilized for preparative purposes [5]. The tert-butoxyl radical is often used as a methyl radical source, generated, for example, by tertbutylhydroperoxide/iron(II) in aqueous sulphuric acid or by UV irradiation of peresters or pyridones [6][7][8][9]. For the prospect of applications targeted at DNA it would be advantageous to avoid both the strongly oxidizing tert-butoxyl radical and the use of ultraviolet light.…”