Glycosidic free radical

Ditellurides, 24 422 Diterpene glycosides, 24 239 Diterpenoid acids, 24 552 Diterpenoids, 24 550-555 labdane family of, 24 573 Di -ferf-alkyl peroxides, 23 439-441 as free-radical initiators, 14 288... 

In this review we have presented a complete and, as far as possible, up to date account of how C-glycosides may be synthesized using C(l) nucleophiles. Free radical based methods, which have provided numerous and useful procedures for C-glycoside synthesis, were beyond the scope of this review and only a few representative examples are mentioned. 

R. Nouguier, C. Lesueur, E. De Riggi, M. P. Bertrand, and A. Virgili, Stereoselective free-radical cyclisation on a sugar template. Hie sulphonyl radical as a synthetic tool for functionalized glycosides. Tetrahedron Lett. 37 3541 (1990). 

For the release of an unaltered base, the sugar moiety must be damaged. In principle, the base could already be released from a radical site at the sugar moiety, i.e. on the time-scale of the lifetime of the DNA radicals. The observation of 2-dRL incorporated into DNA as a product formed upon OH attack shows that a damage at C(l ) contributes to the release of an unaltered base. In the carbohydrate series, hydrolytic scission at the glycosidic linkage when this site contains a free-radical is a well-documented phenomenon, and it has been estimated that the rate of reaction must be faster than 35 s 1 (von Sonntag and Schuchmann 2001). As it stands, it cannot be excluded, that under certain conditions the base release from the C(l ) radical [reaction (38)] occurs in competition to its oxidation [reaction (2)]. In a cellular environment, there is also the reduction of DNA... 

The mechanism of strand breakage in hyaluronic acid must naturally involve the scission of the glycosidic bond. From product studies of the free radical... 

C-Glycosides. Thiophenyl glycosides undergo ready free-radical allylation with allyl- or methallyltri- -butyltin. Thus the L-lyxose derivative 1 reacts with allyltri-/ -butyltin under photochemical initiation to give 2 and 3 in the ratio 90 10. The reaction... 

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