Imide radical

The imido complex [Mo2(cp)2(/r-SMe)3 (/u.-NFl)]" " 25+ undergoes an irreversible one-electron (EC) reduction [70]. Controlled potential electrolysis afforded the amido analog [Mo2(cp)2(/x-SMe)3(/x-NH2)] 26 almost quantitatively after the transfer of IF mol 25+. The amido complex was not the primary reduction product the latter was assigned as a rearranged imide radical (Sch. 18), which is able to abstract a FI-atom from the environment (supporting electrolyte, solvent, or adventitious water) on the electrolysis timescale. In the presence of protons, the reduction of 25+ became a two-electron (ECE) process. This is consistent with the protonation at the nitrogen lone pair of the primary reduction product, followed by reduction of the resulting amido cation... 

The oxygen is chemisorbed on the catalyst. This then reacts with ammonia to produce a chemisorbed imide radical. The imide reacts with a molecular oxygen to yield nitric oxide. 

From the product salts, ThN is obtained by thermal decomposition of the imide radical and separation of the K metal by vacuum distillation. 

The mechanism of the Schmidt reaction has not been established with certainty. Schmidt proposed a mechanism in which the hydrazoic acid is cleaved by the strong mineral acid to nitrogen and the imide radical (NH). This radical is supposed to add to the carbonyl group, followed by a rearrangement either directly or by a Beckmann transformation of an intermediate oxime to the amide. ... 

As we saw when discussing allylic brommation m Section 10 4 N bromosuccm imide (NBS) is a convenient free radical brommatmg agent Benzylic brommations with NBS are normally performed m carbon tetrachloride as the solvent m the presence of peroxides which are added as initiators As the example illustrates free radical bromi nation is selective for substitution of benzylic hydrogens... 

The first use of ionic liquids in free radical addition polymerization was as an extension to the doping of polymers with simple electrolytes for the preparation of ion-conducting polymers. Several groups have prepared polymers suitable for doping with ambient-temperature ionic liquids, with the aim of producing polymer electrolytes of high ionic conductance. Many of the prepared polymers are related to the ionic liquids employed for example, poly(l-butyl-4-vinylpyridinium bromide) and poly(l-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [38 1]. 

In an effort to identify a more stereoselective route to dihydroagarofuran (15), trimethylsilylated alkyne 17 was utilized as a substrate for radical cyclization (Scheme 2). Treatment of 17 with a catalytic amount of AIBN and tri-n-butyltin hydride (1.25 equiv) furnishes a mixture of stereoisomeric vinyl silanes 18 (72% combined yield) along with an uncyclized reduction product (13% yield). The production of stereoisomeric vinyl silanes in this cyclization is inconsequential because both are converted to the same alkene 19 upon protodesiiyiation. Finally, a diastereoselective di-imide reduction of the double bond in 19 furnishes dihydroagaro-... 

Hollaender and Neumann, 1971) as supporting a free-radical induced decomposition of intermediate phenyldi-imide (phenyldiazene) by way of the diazenyl radical [equation (48) cf. Hoffmann and Guhn, 1967]. 

Samarium(II) iodide also allows the reductive coupling of sulfur-substituted aromatic lactams such as 7-166 with carbonyl compounds to afford a-hydroxyalkylated lactams 7-167 with a high anti-selectivity [74]. The substituted lactams can easily be prepared from imides 7-165. The reaction is initiated by a reductive desulfuration with samarium(ll) iodide to give a radical, which can be intercepted by the added aldehyde to give the desired products 7-167. Ketones can be used as the carbonyl moiety instead of aldehydes, with good - albeit slightly lower - yields. 

One of the present authors (31) has developed a series of additives which combine the features of both free radical inhibitors and flame retardants of the tetrabromophthalimide or chlorendic imide type with hindered phenol antioxidant structures such as the following compounds ... 

With ligand 170 (R = Bn), Fahmi reports the formation of an equal amount of byproduct, formulated as the allylic imide 171, Eq. 103. Indeed, Fahmi suggests that this is the correct structure of the same byproduct observed by Katsuki et al. (116) (cf. Section III.A.4, Structure 161). Fahmi suggests that this product may be formed by insertion of solvent in copper benzoate intermediate 172, as illustrated in Scheme 12. The generated copper imidate 174 then reacts with the allylic radical and combines to provide the allylic amination product 175 that rearranges to the observed imide 171. 

Near-infrared (NIR) absorption spectroscopy has been used to characterize the delocalized re-stacks on electronic conducting dendrimers by Miller and coworkers [47-49]. These dendrimers were prepared by peripherally modifying PAMAM dendrimers with cationically substituted naphthalene diimides, and then reduced with one electron per imide group to convert each imide into its anion radical. The re-stacking of these radical anions on these dendrimer surfaces was indicated by an absorbance band beyond 2000 nm in the NIR spectra. 

This radical cyclization strategy was utilized for the synthesis of the smaller fragment silyl ether 54 as well (Scheme 8). Evans aldol reaction of the boron eno-late derived from ent-32 with aldehyde 33, samarium(III)-mediated imide methyl ester conversion, and protecting group exchange led to tosylate 51. Elaboration of 51 to ketone 53 was achieved under the conditions used for construction of the second tetrahydrofuran moiety of 49 from 46. A highly diastereoselective reduc-... 

The photochemistry of imides, especially of the N-substituted phthalimides, has been studied intensively by several research groups during the last two decades [233-235]. It has been shown that the determining step in inter- and intramolecular photoreactions of phthalimides with various electron donors is the electron transfer process. In terms of a rapid proton transfer from the intermediate radical cation to the phthalimide moieties the photocyclization can also be rationalized via a charge transfer complex in the excited state. 

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