Hydroxyl complexes, amine

In the same spirit DFT studies on peroxo-complexes in titanosilicalite-1 catalyst were performed [3]. This topic was selected since Ti-containing porous silicates exhibited excellent catalytic activities in the oxidation of various organic compounds in the presence of hydrogen peroxide under mild conditions. Catalytic reactions include epoxidation of alkenes, oxidation of alkanes, alcohols, amines, hydroxylation of aromatics, and ammoximation of ketones. The studies comprised detailed analysis of the activated adsorption of hydrogen peroxide with... 

It was suggested by Harrod ( 5) that the ratio k2/kl is virtually independent of temperature and composition but dependent on the amine and epoxide used. Dusek et al (11) state that k and k2 depend on the autocatalytic effect of the hydroxyls and retardation caused by hydroxyl complexing with amine hydrogens but present no evidence to support this statement. They also mention data to support the constancy of k2/ki. 

An equilibrium is set up in equations (lb) and (2b) and the zero order behavior observed for the epoxy consumption may be attributed to the slow breakdown and low concentration of the ternary intermediate, Structures 2 and 3. On the other hand, if the hydroxyls are more reactive, equilibrium formation of the intermediates, Structures 4 and 5 will be far to the right and equations (la) and (2a) may be neglected. It may also be assumed that when the hydroxyls are much more tightly bound to the amine or epoxy, shifting equations (lb) and (2b) to the left, then the association of hydroxyl complexes with epoxy or amine, equations (lb) and (2b), tend to control the rate of reaction and not the breakdown of ternary complex, equations (Ic) and (2c). This would cause an apparent second order reaction. 

Further evidence of the probability of the Mika and Tanaka model (of hydroxyls complexing with amine) is an observation during experimentation. In Resin III, the isopropyl alcohol was not totally soluble when the mix was homogenized it formed an emulsion. As amine was added, the mixture became miscible as evidenced by the almost immediate disappearance of turbidity. 

The first reaction is the hydroxyl complexing with amine ... 

Amine Donors. Complexes with l,3-bis[2(S)-aminomethyl-l-pyrrolidinyl]propane and other optically active tetra-amines containing pyrrolidinyl groups with six-membered chelate rings have been studied, and the stereochemistry of the complex depends on the position of the two pyrrolidinyl groups in the ligand. Studies of ability of similar complexes to hydrolyse esters have been reported. Stability constant measurements for nickel(ii) monoamine complexes have been made in a number of hydroxylic solvents. Magnetic and optical spectral measurements of some nickel(ii) succinimide and mixed amine-succinimide complexes indicate that... 

In this type o-f complexes Psingle bond. Their -formation by deprotonation o-f PhNHOH by the metal-oxo moiety supports the view that the 2-bQnded PhNO ligand can be considered as the bis anion o-f the hydroxyl amine. These complexes can also be obtained by the -following reac t i on [24]... 

Similarly, Blay, Pedro, et al. have reported the synthesis of 8-lactones via a catalytic highly enantioselective Henry addition of methyl 4-nitrobutyrate to aldehydes [67] (Scheme 27). The Henry reaction between aldehyde 145 and methyl 4-nitrobutyrate in the presence of Cu(OTf)2-amine 147 complex and Et3N afforded the addition product with moderate diastereoselectivity and with excellent enantio-selectivity. Protection of the resulting hydroxyl group provided intermediate 148. Removal of the nitro group present in 148 by treatment with BusSnH/AIBN was followed by deprotection/lactonization under acidic conditions to give 8-lactone 151 with good enantioselectivity. 

With the success in Lewis acid-catalyzed thiol conjugate addition reactions mentioned above, we further tried to apply the J ,J -DBFOX/Ph-nickel(II) aqua complex catalyst to the catalyzed asymmetric conjugate addition reactions of hydroxyl-amines [88, 89]. However, after some preliminary examinations, we found that... 

A seemingly complex heterocycle which on close examination is in fact a latentiated derivative of a salicylic acid shows antiinflammatory activity. It might be speculated that this compound could quite easily undergo metabolic transformation to a salicylate and that this product is in fact the active drug. Condensation of acid 134 with hydroxyl amine leads to the hydroxamic acid 135. Reaction of... 

The ion-pair complex formed by the interaction of hydroxobis(8-quinolyloxo) vanadium (V) [VOQ2OH] and /i-butyl amine is also effective in photoinitiation of polymerization of MMA in bulk and in solution [40]. The quantum yield of initiation and polymerization determined are equal to 0.166 and 35.0, respectively. Hydroxyl radical ( OH) is reported to be the initiating radical and the following photoreaction is suggested ... 

Melt reaction mechanisms of tertiary aliphatic amine catalyzed phenolic-epoxy reactions were proposed to begin with a trialkylamine abstracting a phenolic hydroxyl proton to form an ion pair (Fig. 7.36). The ion pair was suggested to complex with an epoxy ring, which then dissociated to form a /1-hydroxycther and a regenerated trialkylamine.87... 

When hot, ammonia and compounds, which contain nitrogen-hydrogen bonds eg ammonium salts and cyanides react violently with chlorates and alkaline perchlorates. Diammonlum sulphate, ammonium chloride, hydroxyl-amine, hydrazine, sodamide, sodium cyanide and ammonium thiocyanate have been cited. So far as hydrazine is concerned, the danger comes from the formation of a complex with sodium or lithium perchlorate, which is explosive when ground. Many of these interactions are explosive but the factors which determine the seriousness of the accident are not known. 

The first test case was the ferrous high-spin state (Fe, S = 2) in the picket-fence porphyrin acetate complex [Fe(CH3COO)(TPpivP)] [13, 23], which is a model for the prosthetic group termed P460 of the multiheme enzyme hydroxyl-amine oxidoreductase from the bacterium Nitrosomonas europeae. Both the picket-fence porphyrin and the protein P460 exhibit an extraordinarily large quadrupole splitting, as observed by conventional Mossbauer studies [56]. 

It was shown that complexes 19 of the zwitterionic precursors of ortho-quinone methides and a bis(sulfonium ylide) derived from 2,5-di hydroxyl 1,4 benzoquinone46 were even more stable than those with amine N-oxides. The bis(sulfonium ylide) complexes were formed in a strict 2 1 ratio (o-QM/ylide) and were unaltered at —78 °C for 10 h and stable at room temperature under inert conditions for as long as 15—30 min (Fig. 6.18).47 The o-QM precursor was produced from a-tocopherol (1), its truncated model compound (la), or a respective ortho-methylphenol in general by Ag20 oxidation in a solution containing 0.50-0.55 equivalents of bis(sulfonium ylide) at —78 °C. Although the species interacting with the ylide was actually the zwitterionic oxidation intermediate 3a and not the o-QM itself, the term stabilized o-QM was introduced for the complexes, since these reacted similar to the o-QMs themselves but in a well defined way without dimerization reactions. 

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