Reactions with protons

Aziridinones undergo two types of selective ring opening by nucleophiles <68AG(E)25). Reaction with proton-containing nucleophiles, e.g. water, alcohols, thiols, amines and mineral acids, leads exclusively to amides (339), corresponding to an C —N bond rupture. 

Other reactions with protonic reagents are 20H (aq) + FCIO2--------> ClOa + F + H2O... 

The Grignard reagents prepared from the activated magnesium appear to react normally with electrophiles. Thus reactions with proton donors, ketones, and carbon dioxide afford hydrocarbons, alcohols, and carboxylic acids, respectively. The reductive coupling of ketones to pinacols had also been accomplished with the activated magnesium. ... 

The now familiar alternatives of visual and potentiometric detection are available. A number of organic dyes form coloured chelates with many metal ions. These coloured chelates are often discernible to the eye at concentrations of 10 6-10 7 mol dm 3 and can function as visual indicators. Most metal ion indicators will also undergo parallel reactions with protons bringing about similar colour changes. Hence, a careful consideration of pH is prudent when selecting an indicator. Some typical indicators appear in Table 5.9. Of these, eriochrome black T, which forms red complexes with over twenty metal ions, is amongst the most widely used. Its behaviour will serve as a general example of indicator function. 

Conversely, Gourec et al. suggested a mechanism involving a non-metallic active site.85 In the proposed mechanism, based on XPS, SIMS, and CV analysis, dioxygen reacts with protonated nitrogen surface species to form oxidized nitrogen surface species and water. After further reaction with protons and electrons, the oxidized nitrogen is reduced, and water is produced. 

Thus, in the presence of water or other proton sources, the O2 ion forms HOO —the strong base. Therefore, many reactions that are ascribed to the superoxide ion are actually reactions with proton donors. These reactions produce effective oxidants (O2 and HOO ) and strong bases (HOO, OH , or B ). This route of base generation finds its applications in synthetic practice. Thus, ethyl... 

Compound 211 and several related compounds are readily accessible by stereospecific deprotonation of the appropriate optically active carbamic esters with 5-BuLi/TMEDA ° . Much of the knowledge about the stereochemical course of substitution in benzyUithium derivatives was obtained from experiments with these compounds. Only the reaction with proton acids, aliphatic aldehydes, ketones or esters as electrophiles proceed with retention for alkyl, silyl and stannyl halides, acid chlorides. 

The microenvironmental effect of various sulfonated polystyrene beads was studied using the Prins reaction as a probe.372 Reaction rates were found to be lower when carbomethoxy or carbobutoxy neighboring groups were present compared to phenyl. A less ionic microenvironment appears to allow for a higher concentration of styrene within the polymer and leads to an immediate reaction with protonated formaldehyde. 

Consider the extraction of M"+ from aqueous solution into organic solution by reaction with protonated ligand, HL ... 

In the case of hydrogen evolution and electrode reactions with proton... 

Subsequently the work of R. F. Merritt clearly established the selectivity of additions of fluorine to double bonds in CFC13 at —78°C in preference to reactions with protons. Merritt and co-workers studied such unsaturated systems as indenes and acenapthenes (83), A4 cholestenone (84), 1,1-diphenyl-ethylene (85), Schiff s bases (86), and acetylenes (87). 

In the associative mechanism, the reaction of olefin with metal hydride produces alkyl species while the reaction with proton produces alkyl cations. In contrast to the covalent bonding of alkyl species, alkyl cations are bound to catalytic sites by ionic force. 

Aromatic amines react uniquely with various oligomers derived from cyclic systems as carbon nucleophiles and the result is a remarkable array of annela-tion processes [142] as illustrated by the reaction with Proton-Sponge (117), shown in Scheme 74. 

If the index is positive then the solution is supersaturated, whereas a negative value indicates understaturation. When modelling mineral solubility with other reactions involving protons it may be necessary to write the dissolution reaction of the solid phase as a dissolution reaction with protons. Consider the dissolution of gibbsite ... 

In Section 5.2.4.5 the solubility fCso of gibbsite as a reaction with protons was calculated to be... 

The chemistry of the hydrazido( 1 -) ligand is in its infancy. Nevertheless, it is clear that such species can, in certain cases, undergo further reactions with protons to release organohydrazine. Whether or not hydrazido(l-) complexes or their organo analogs are capable of yielding an imido complex and an amine in a clean reaction as shown in reaction (58) remains to be demonstrated. 

In engine oil acid-base reactions with proton transfer, logKBH+A. > 103, occurs in systems, e.g., sulfuric acid + carbonate or sulfuric acid + phenate however, the majority of reactions belong to the group without proton transfer, logKB HA < 103, e.g., carboxylic acid + succinimide or phenol + succinimide. 

To verify this idea the methyl substituted phosphate complex 62 was synthesized and separated into its optical antipodes. The reaction with protons was not regiospecific but to a certain extent stereoselective, and the isolation of optically active phosphorane 63 was greatly helped by fortunate incursion of a spontaneous racemate separation 73>. 

The cobalt-silicon compounds described here undergo reactions with protonic molecules such as hydrogen chloride, Lewis bases such as trimethylamine, and oxidizing agents. 

As indicated by titration data (Figures 6 and 7), binding of copper in both Neuse and Newport River water decreases with increasing total copper in a manner consistant with a stepwise titration of a number of different ligands and/or binding sites. Binding of copper increases with increasing pH consistant with reactions with protonated weak acids. 

This is a mechanism of polyolefin cracking. The main polymer chains are reduced by reaction with protons or other carbonium ions, followed by chain scission giving C30-C50 oligomeric hydrocarbons [7], As a result of further, secondary cracking reactions by P-scission of C30-C50 hydrocarbons, gas and lower-molecular liquid C10-C25 hydrocarbons are produced. Other reactions are double bond and saturated hydrocarbon isomerization as well as methyl group shift . 

When a base catalyzed reaction with proton transfer in the first step is carried out in D20 solution, the substrate exchanges its acidic hydrogen with the deuterium of the solvent before the reaction takes place if the mechanism is fast pre-equilibrium proton transfer with subsequent slow step. If, on the other hand, hydrogen exchange does not occur prior to the reaction, it may be concluded that proton transfer is the rate-determining step. 

Several types of functional groups that contain C-Z o bonds are listed in Table 3.2. The electronegative heteroatom Z creates a polar bond, making carbon electron deficient. The lone pairs on Z are available for reaction with protons and other electrophiles, especially when Z = N or O. 

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