Amine relative

In the context of the stability of the nitrosoamine intermediate in the diazotization of heteroaromatic amines relative to that in the case of aromatic amines, the reversibility of diazotization has to be considered. To the best of our knowledge the reverse reaction of a diazotization of an aromatic amine has never been observed in acidic solutions. This fact is the basis of the well-known method for the quantitative analysis of aromatic amines by titration with a calibrated solution of sodium nitrite (see Sec. 3.3). With heteroaromatic amines, however, it has been reported several times that, when using amine and sodium nitrite in the stoichiometric ratio 1 1, after completion of the reaction nitrous acid can still be detected with Kl-starch paper,... 

Imines, either acyclic or macrocyclic but invariably multidentate, have a rich coordination chemistry that has been investigated at length. The 7r-accepting ability of imine donors results in the stabilization of lower oxidation states relative to their saturated amine analogs, and there exist many air-stable divalent imine complexes of Co, in contrast to amine relatives. The hexa-methyl-diene (52) has been the most intensively studied ligand of this class, particularly when complexed with Co. In addition, Co complexes of the dimethyl (53),295,296 tetramethyl (54),297 pentamethyl (55)298 and octamethyl (56)299 macrocyclic dienes are also known. In the presence of... 

Surfactants that form micelles have also been shown to accelerate the formation of nitrosamlnes from amines and nitrite (33.) A rate enhancement of up to 80 0-fold was observed for the nitrosation of dihexylamine by nitrite in the presence of the cationic surfactant decyltrimethylammonium bromide (DTAB) at pH 3.5. A critical micelle concentration (CMC) of 0.08% of DTAB was required to cause this effect, which was attributed to a micelle with the hydrocarbon chains buried in the interior of the micelle. The positively-charged ends of the micelle would then cause an aggregation of free nitrosatable amine relative to protonated amine and thus lead to rate enhancements. Since surfactants are commonly used in water-based fluids (25-50% lubricating agent or 10-2 0% emulsifier in concentrates), concentrations above the CMC of a micelle-forming surfactant could enhance the formation of nitrosamines. 

Tanaka and Mika 42) suggest that the higher basicity of amine relative to epoxide makes the formation of an amine-proton donor adduct more likely, and they proposed the following equations as an alternative to Eqs. (3-12) and (3-13). 

In our experiments, no CO inhibition was observed, instead the rhodium-catalyzed hydrogenation of aldehydes in the presence of amines showed a first-order dependence on both CO and H2 (Table V). The absence of any significant inhibition by CO is attributed to lower operating temperatures and lower H2 pressures feasible in the presence of amine, relative to the earlier reports (16). Maxima in the rates are reported only at CO partial pressures exceeding 1000 psig (11, 16) and were neither expected nor observed in this investigation. 

In presence of morpholine, (17) catalyzes the hydrogenation of nitrobenzene to aniline.61 A near twofold excess of the amine relative to (17) was used. At a higher excess, catalysis ceased. This was attributed to formation of a bis-morpholine complex. The hydrogenation proceeds best in solvents such as acetone, ethyl acetate or THF.62 The transfer of the first hydrogen atom to nitrobenzene was found to be rate determining and a dinuclear nitrobenzene complex (18) was postulated. The base (B) is morpholine. 

Any structural feature that stabilizes the ammonium ion (relative to the free amine) shifts the reaction toward the right, making the amine a stronger base. Any feature that stabilizes the free amine (relative to the ammonium ion) shifts the reaction toward the left, making the amine a weaker base. 

Oxime Conditions Yield (%) Rearrangement (rel. %) Amine (rel. %) Exo.endo... 

What conclusions may be drawn from these results as to the cause(s) of the reduced base strength of aromatic amines relative to saturated aliphatic or alicyclic amines Explain. 

The gold-catalysed intramolecular amination of allylic alcohols with alkylamines has provided substituted pyrrolidine and piperidine derivatives with excellent yields and selectivities (up to 99% yield and 96% ee)." The reaction mechanism was found to be consistent with the net syn addition of the amine relative to the departing hydroxyl group (Scheme 6). The synthesis of functionalized carbazoles through gold-catalysed deacylative cycloisomerization of 3-acylindole/ynes has been reported. ... 

Aniline and N-methylaniUne derivatives are the most reliable substrates for the Hartwig-Buchwald coupling, and they experience a high level of functional group tolerance. Similar to the coupling of primary amines, the double arylation of aniline can be a competing side reaction. A slight excess of the amine relative to the aryl component usually diminishes this side reaction. 

Figure 9.19. Mass spectrum of bis(3-methylbutyl)amine. (Relative abundance of the m/z 158 peak increases with increasing sample pressure.)...

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