Radical externalism

Varveris H, Delakas D, Anezinis P, et al. Concurrent platinum and docetaxel chemotherapy and external radical radiotherapy in patients with invasive transitional cell bladder carcinoma. A preliminary report of tolerance and local control. Anticancer Res 1997 17(6D) 4771 1780. 

It is important to note that saturated fatty acids are not immune to effects of oxidation. The strongly oxidizing radicals HO and RO abstract hydrogens at reasonable rates even from saturated fatty acids (10 for RO and 10 for HO ). The subsequent LsatOO radicals then abstract hydrogens from neighboring unsaturated fatty acids and thus can be sources of external radicals initiating radical chains in PUFA s (9, 208). 

Platinum forms two distinct series of these complex salts, in one of which platinum is bivalent and in the other quadrivalent. In the platinous series the metal holds four molecules or radicals coordinated with it to form the complex radical, which in turn may hold two external radicals. Thus when ammonia is added to platinous chloride and the precipitate so formed is boiled with ammonia, a compound is formed having the composition [(NH3)4Pt Cl2. The ammonia groups may be partially or entirely replaced by acid groups such as Cl, N02, SCN, etc. Thus we have four classes of derivatives which correspond to the following general formulae, X being used to represent any univalent acid radical and It any univalent basic radical. 

Abstraction a to an oxygen atom. Formation of a bicyclic system starting from a free alcohol is depicted in Scheme 40 (Eq. 40.1) [136]. Malacria has recently reported the preparation of enantiomerically pure 1,2,3-triols via an unusual 1,4-hydrogen atom abstraction followed by a highly diastereoselective trapping of the resultant alkoxy substituted radical with acrylonitrile (Eq. 40.2) [19]. In this particular case, intramolecular reaction with the alkenyl group (3-cxo-trig or A-endo-ing cyclization) is not feasible therefore, reaction with an external radical trap is favored. 

Even though some have argued [28] that there are enzymatic reactions in which coenzyme B12 acts as a simple free radical initiator for a chain process, this is not what we are hoping to mimic. Thus it is clear that some of the properties of cyclodextrin-Bi2 are quite promising, but that we must learn how to keep the radicals bound in the cavity so that external radical chain processes do not take over. There is still plenty to do, but the surprising properties of cyclodextrin-Bi2 furnish a very good start. 

Changes in number-average molecular weight with conversion of MA to PMA in an RT process using V-70 as the external radical source. Polymerization mediated by (A) (TAP)Co and block copolymerization mediated by (B) (TAP)Co-PtBA (PDI = 1.09, M = 3.86x 10 ). Reprinted with permission from ref. 6. Copyright 2011 American Chemical Society. 

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