The reactions of the hydroxyl radical with a number of compounds containing the unit-CHX-CHY-, where X = OH or OMe and Y = OH, OAc, Halogen, or a protonated amino-group, have been studied by e.s.r. spectroscopy. The transient species involved have been identified on the basis of their hyperfine splittings and g-factors; in the case of the radical *CH(OH)*CH2NH3+ and its derivatives, clear trends in the proton and nitrogen splittings are observed as the NH hydrogen atoms are successively replaced by methyl groups, and these have been rationalised in terms of an interaction involving both hydroxy-and amino-substituents.The data not only support theview that radicalscontaining the fragment-C(0H)-C(OH)< undergo acid-catalysed elimination of water but also reveal further details of this reaction and information about related heterolytic processes; for example, there is evidence that the radical cation M e k H -t H, is formed transiently from the radical .CH(OMe)-CH,X (X = CI or OAc). Amines do not appear to fragment heterolytically from radicals of the type -CH(OH).CH2NR3+, but the formation of the species Me,"+ from the choline cation suggests that the C-N bond in the species *CH (OH)*CH2NMe3+ readily undergoes homolysis.previously been adduced, from e.s.r. generated by y-irradiation of an aqueous solution of the spectroscopic observations, that when ethylene glycol is oxidised with the hydroxyl radical [from the titanium-(111) ion-hydrogen peroxide system or photolysis of hydrogen peroxide 3], the first-formed radical (1) undergoes dehydration to give the radical (2) in an acidcatalysed reaction (i).2,3 A number of related transformations has been documented,2 and support for the occurrence of reaction (i) has subsequently been obtained from an investigation in which the radical (1) was
Data on family caregiver stress obtained before, during, and following respite suggest that stress was moderated by an in-hospital respite program for patients with Alzheimer's disease. Although short-term benefits may be realized for caregivers, in-hospital Alzheimer's respite care may present a particular risk for patient decline, adverse events, and institutionalization.
17α-Methyl-11β-arylestradiol (17α-methyl-11β-(4-(2-(1-piperidinyl)ethoxy)phenyl)estra-1,3,5(10)-triene-3,17β-diol) is a new
molecule developed by Aventis Pharma for the treatment of
osteoporosis. It was produced on the pilot plant scale from the
norsteroid intermediate ethylene deltenone (3,3-ethylenedioxyestra-5(10)-9(11)-diene-17-one). Stereoselective epoxidation of
the 5(10)-olefin was performed by hydrogen peroxide and
hexachloroacetone, the most selective of the systems tested. The
11β-aryl appendage was introduced as a cuprate generated
catalytically from the related Grignard reagent. The A-ring was
aromatized by a mixture of acetyl bromide and acetic anhydride. This reaction was optimized by a Design Of Experiments
carried out on an automated workstation. The advantages and
limits of this approach are discussed. The last step consisted of
the stereospecific alkylation of the 17-ketone by methylmagnesium bromide and dehydrated cerium trichloride. The drug
substance was crystallized as a hydrate (overall yield = 23%).
The mi-anion CH2 : NO2has been used as a spin trap for a variety of organic radicals, which have been generated in aqueous solution by reactions effected by the hydroxyl radical or the sulphate radical anion, SO,*-.The resulting species have been identified by their e.s.r. parameters, confirmation being obtained where necessary by independent generation of the species from the appropriate nitro-compound and a one-electron donor (*CMe,*OH). Of especial value in the analysis, splitting is observed not only from the (p-) methylene protons in RCH2N02*-but also in almost all cases from y-protons and, in some cases, from 6-protons; further, aN and a,(p-CH,) are significantly dependent upon structure. For radicals of the type CXYZ*CH2*N02*-, the splittings of the two p-methylene protons are unequal, evidently as the result of the chirality of the neighbouring carbon atom. In some cases information has been obtained about the mechanisms of reaction, as in comparison of the reactions of *OH and SO4*-with carboxylate ions and of those of 2-chloro-and 2-iodoethanol with *OH. THERE has been considerable success in the last decade in generating highly reactive organic radicals in solution a t concentrations above the detectable limit for e.s.r. spectroscopy ; the methods include electron-bombardment, developed by Fessenden and Schuler,2 the use of inorganic redox systems [especially titanium(Ii1) ionhydrogen peroxide] ,3 and ultraviolet irradiation . 4 p However, some species can still defy detection; for example, there is evidence for1the rapid formation of the phenyl radical by the one-electron reduction of benzenediazonium ion in aqueous solution by, for example, the radical *CMe,*OH, but the e.s.r. spectrum of the phenyl radical cannot be observed.6 Moreover, there may be a need to test for the presence of a particular radical in a 1
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