Nitrogen transfers

Problems sulfur and nitrogen transferred to the products (and coke) Solutions feed hydrotreating, reduction of S, N, Conradson carbon, metals Results higher quality products reduction in pollution better yields of valuable products reduced post-treatment... 

At high temperature, sodium and its fused haHdes are mutually soluble (14). The consolute temperatures and corresponding Na mol fractions are given in Table 3. Nitrogen is soluble in Hquid sodium to a limited extent, but sodium has been reported as a nitrogen-transfer medium in fast-breeder reactors (5) (see Nuclearreactors). 

With respect to the monoazacrown ethers, Pedersen has utilized some interesting technology which is applicable to this class of compounds. For example, he has used benzylamine as a nitrogen transfer agent. This is accomplished by the sequence shown in Eq. (4.5). In the same report, Pedersen utilized the r-butyloxycarbonyl (tBOC)... 

A commercial silver alloy in the form of wire or foil is suitable for this determination. Clean the alloy with emery cloth and weigh it accurately. Place it in a 250 mL conical flask, add 5 mL water and 10 mL concentrated nitric acid place a funnel in the mouth of the flask to avoid mechanical loss. Warm the flask gently until the alloy has dissolved. Add a little water and boil for 5 minutes in order to expel oxides of nitrogen. Transfer the cold solution quantitatively to a 100 mL graduated flask and make up to the mark with distilled water. Titrate 25 mL portions of the solution with standard 0.1 M thiocyanate. 

In 1983, Groves and Takahashi demonstrated that a nitrido-Mnvporphyrin underwent a nitrogen-transfer reaction via a tV-trifluoroacetylnitrenoid species to give an aziridine, when it was treated with trifluoroacetic anhydride (TFAA) in the presence of olefins (Scheme 31).141... 

Later, Carreira et al. reported that nitrido-Mnv(salen) also underwent a nitrogen-transfer reaction under similar reaction conditions.142 An asymmetric version of this reaction has been realized by using the chiral nitrido-Mnv(salen) (44) (Scheme 32).143 When trifluoroacetic acid... 

Wolfe has presented an excellent description of the systematic application of stable and radioactive isotope tracers in determining the kinetics of urea production, urea recycling, and interorgan nitrogen transfer in living systems. 

This methodology is also an important and potentially valuable method for C—N bond formation using the amination of carbon nucleophiles with electrophilic nitrogen transfer reagents (Scheme 1) Amination of ordinary carbanions and a-carbanion derived from carbonyl compounds and nitriles provides an important method for the synthesis of amines and a-amino carbonyl compounds and nitriles", respectively. For this purpose, a number of electrophilic amination reagents, which are synthetic equivalents of the R2N+ synthon, have been developed and the synthetic potential of electrophilic amination of carbon nucleophiles has been studied in detail . ... 

Reports of atom-transfer reactions for complexes of Os in high oxidation states chiefly appear in three areas hydride transfer, oxotransfer, and nitrogen transfer. 

Nitrogen-transfer reactions of osmium imido species lead to cis diamines or amino alcohols. Reaction of 0s02(N-/-C4H9)2 [63174-13-0] with olefins produces vicinal diamines after reductive cleavage. Catalytic oxyamination of olefins using chloramine-T or AJ-chlor-AJ-argenocarbamates yields vicinal hydroxy toluenesulfonamides (112) or carbamates (113), respectively, which maybe deprotected to vicinal amino alcohols. 

Transamination Is the Most Widespread Form of Nitrogen Transfer... 

Depending on the type of iron catalyst, the reaction seems to take different mechanistic pathways. According to Johannsen and Jorgensen s results, the catalytic cycle starts with the formation of nitrosobenzene 32 either by disproportionation of hydroxylamine 29a to 32 and aniline in the presence of oxo iron(IV) phthalocyanine (PcFe4+=0) or by oxidation of 29a [131]. The second step, a hetero-ene reaction between the alkene 1 and nitrosobenzene 32, yields the allylic hydroxylamine 33, which is subsequently reduced by iron(II) phthalocyanine to afford the desired allylic amine 30 with regeneration of oxo iron(IV) phthalocyanine (Scheme 3.36). That means the nitrogen transfer proceeds as an off-metal reaction. The other byproduct, azoxybenzene, is probably formed by reaction of 29a with nitrosobenzene 32. 

On the other hand, for allylic aminations very promising results have been realized with regard to regioselectivity, catalytic activity and substrate scope. However, further efforts are necessary to find nitrogen transfer reagents which allow convenient deprotection and isolation of the allylic amine. 

The 3-aryl-N-BOC-oxaziridines 140 are prepared by the oxidation of the corresponding benzaldimines 139 using the lithium salt of m-CPBA under aprotic conditions. These oxaziridines can then be used as protected-nitrogen transfer agents [95TL1439]. 

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