Amidation oxidative

FIGURE 7.27 Ester (IR 1825-1815 cm4) and amide IV-oxide (amide 3-oxide) (IR 1750-1730 cm4) forms of benzotriazole adducts.94 R = R O and R 0C(=0)-Xaa. Compounds with R = tBuO and PhCH2 are amide forms.97 The product from reaction of Trt-methionine and HOBt is the amide 3-oxide96 (Trt = trityl = triphenylmethyl). Note that the atoms bearing the oxygen atoms are numbered differently in the two compounds. 

Recently an oxidative amidation protocol, employing copper (I) as a catalyst, was developed by C.-J. Li [14]. The proposed mechanism, shown in Scheme 14.1, involves nucleophilic addition of the amine free base 8 to aldehyde 7 to afford hemiaminal intermediate 9, which is then oxidized by copper(I)/t-butyl hydrogen-peroxide (Cu(l)/TBHP) to generate the desired amide products 10 [15, 16]. 

The utility of the method was demonstrated with a variety of electron-rich and electron-poor aryl aldehydes, but the method was not suitable for aliphatic aldehydes. No racemization was observed in the copper-catalyzed oxidative amidation reaction when an optically active amine, (S)-valine methyl ester, was employed. 

Torisawa [17] developed an alternative oxidative amidation of aldehydes using palladium chloride (PdCl2)-xantphos complex as a catalyst. The use of hydrogen peroxide (H2O2)-urea complex as oxidant prevents the formation of imine from the carbinolamine intermediate and minimizes the level of benzoic acid side... 

Complexes with organa -phosphorus and -arsenic oxides, amine oxides, amides, sulfoxides and... 

Oxidative amidation of aldehydes can be achieved with primary amine hydrochlorides, Cul as catalyst, and r-BuOOH as oxidant, probably via a carbinolamine intermediate.343... 

In any case, the region of accelerated aging must be limited by physical transitions (melting, glass transition), since the kinetic parameters undergo practically unpredictable discontinuous variations at these transitions, as illustrated by the example of oxidation (amide growth in an amide-cured epoxy) (Fig. 14.22). 

Oxidation a to nitrogen.1 In the presence of this Ru catalyst, f-BuOOH oxidizes amides to the a-(f-butyldioxy)amides in high yield, probably via an oxoruthe-... 

In general, on chemical modification carbon nanotubes exhibit much less toxicity or nontoxicity to living cell lines that have been investigated so far.117,118 For instance, Dumortier et al. conducted an in vitro cell uptake study of the functionalized SWNTs with B and T lymphocytes and macrophages.117 Two types of functionalized SWNTs were used, one prepared via 1,3-dipolar cycloaddition reaction and the other obtained through oxidation/amidation treatment. Both types of the functionalized nanotubes were rapidly taken up by lymphocytes and macrophages without affecting the overall... 

SCHEME 3.16 Oxidative amide trioxadecalin construction in the synthesis of theopederin D. 

C4HsCd04 Noncombustible solid. The solution is basic reacts with acids, producing heat. Incompatible with strong oxidizers, elemental sulfur, selenium, sulfides, tellurium, nitrates. In the heat of fire, toxic cadmium oxide fumes may form. CADMIUM BROMIDE (7789-42-6) CdBrj Noncombustible solid. Hydrolyzes in water, forming cadmium and bromic acid. Reacts with sulfides. Aqueous solution is inconqiatible with potassium. Incompatible with sulhiric acid, alkalis, ammonia, aliphatic amines, alkanolamines, alkylene oxides, amides, epichlorohydrin, organic anhydrides, isocyanates, nitromethane, vinyl acetate. 

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