Reactions in alkaline solution

Reviews176 of the chemistry of the unsaturated sugars include discussions of their reactions in alkaline solution only a brief discussion of the glycals and 2-hydroxyglycals will be given here. 

Hydrolysis stops at amide stage if R is a ferf-alkyl group H202 accelerates the hydrolysis reaction in alkaline solution (Section 24-3B). 

Sherman WV (1967a) Photosensitized chain reactions in alkaline solutions of nitrous oxide in 2-pro-panol. J Am Chem Soc 89 1302-1307... 

Sherman WV (1967b) Light-induced and radiation-induced reactions in methanol. I. y-Radiolysis of solutions containing nitrous oxide. J Phys Chem 71 4245-4255 Sherman WV (1967c) The y-radiolysis of liquid 2-propanol. III. Chain reactions in alkaline solutions containing nitrous oxide. J Phys Chem 71 1695-1702 Silva C, Walhout PK, Yokoyama K, Barbara PF (1998) Femtosecond solvation dynamics of the hydrated electron. Phys Rev Lett 80 1086-1089... 

Biuret Reaction. The particular capabilities of the stop-ped-flow vidicon system have been used to help explain some unusual behavior in the biuret reaction. The biuret reaction is the basis for the standard clinical chemistry technique for determining the total protein content of human blood serum (23). It involves a complexation reaction, in alkaline solution, between the cupric ion (Cu2+) and the peptide bonds of the protein. In the standard biuret technique, the reaction is allowed to go to completion and then the absorbance of the copper-protein complex is measured at 55 nm. This technique tends to be rather slow since the reaction, although very rapid over the first few seconds, does not go to completion for at least 20 to 30 minutes. 

Addition Reaction. The double bond of dehydroalanine and e-methyl dehydroalanine formed by the e-elimination reaction (Equation 6) is very reactive with nucleophiles in the solution. These may be added nucleophiles such as sulfite (44). sulfide (42), cysteine and other sulfhydryl compounds (20,47), amines such as a-N-acetyl lysine (47 ) or ammonia (48). Or the nucleophiles may be contributed by the side chains of amino acid residues, such as lysine, cysteine, histidine or tryptophan, in the protein undergoing reaction in alkaline solution. Some of these reactions are shown in Figure 1. Friedman (38) has postulated a number of additional compounds, including stereo-isomers for those shown in Figure 1, as well as those compounds formed from the reaction of B-methyldehydroalanine (from 6 elimination of threonine). He has also suggested a systematic nomenclature for these new amino acid derivatives (38). As pointed out by Friedman the stereochemistry can be complicated because of the number of asymmetric carbon atoms (two to three depending on derivative) possible. 

O Sullivan and White [563] recently investigated formaldehyde oxidation at thermally prepared Ru02 electrodes. Two waves were observed for this reaction in alkaline solution (Fig. 24), the first wave beginning at 0.6V... 

It is known that the halogen or OTf ligand on R-Pd-X (1) is readily displaced by an alkoxy, hydroxy, or acetoxy anion to provide a basic R-Pd-OR" (4) complex, as is seen in the syntheses of 6 and 7. Thus, available information indicates that there are two transmetalation processes (path A and path B) for the crosscoupling reaction in alkaline solution however, it is not yet obvious in many reactions which process is predominant. It was recently demonstrated that the reaction of 9-alkyl-9-BBN (10) proceeded through the former process (path A) and the latter (path B) was predominant in a less acidic 9-oxa-lO-borabicy-clo[3.3.2]decane (14) [23] (Scheme 3).NMR study revealed the exclusive formation of an ate-complex (11) between 10 and NaOH whereas the corresponding 14 remained unchanged with an added base. The reactions were zero-order in... 

Oxygen evolution is a more complex reaction, involving the transfer of four electrons. The overall reaction in alkaline solutions is... 

Fig. 7. Alkali metal ion catalysis for the [WiCNlg] —SOs reaction in alkaline solution. Reprinted from Dennis et al. (78). Copyright 1983, Pergamon Press Ltd.

Weiss represented the rates of reaction in alkaline solution by the equation... 

Benzalazine is in slightly acid solution reduced to benzylamine in a six-electron reduction, whereas it forms benzaldehyde benzylhydrazone in a two-electron reaction in alkaline solution [1]. Benzaldehyde benzylhydrazone is reduced in acid solution to benzylamine in a four-electron reaction at potentials slightly less negative than those of benzalazine, so it is not quite clear whether benzaldehyde benzylhydrazone is an inteimediate in acidic solution or whether there is initially a cleavage of the central nitrogen-nitrogen bond. 

As already discussed (Sec. 17.5), phenols are converted into ethers by reaction in alkaline solution with alkyl halides methyl ethers can also be prepared by reaction with methyl sulfate. In alkaline solutions a phenol exists as the phenoxide ion which, acting as a nucleophilic reagent, attacks the halide (or the sulfate) and displaces halide ion (or sulfate ion). 

Mader, . M. "Kinetics of the Hydrogen Peroxide-sulfite Reaction in Alkaline Solution," J. Am. Chem. Soc. 1958, 80, 2634-2639. 

Successive elimination of an alkoxy group adjacent to an active hydrogen atom and intramolecular Cannizzaro reactions in alkaline solution, such as are found in saccharinate formation, are demonstrated by the conversion of 2-hydroxy-3-methoxy-3-phenylpropiophenone (X) to a salt of 2,3-diphenyllactic acid (XI). 

Quinone methides are frequently reported as intermediates from irradiation of arenes having a methyl or substituted methyl group in the 2-position to a carbonyl or nitro group (H-abstraction) or a hydroxy function (formal loss of water). The latter process has been studied with pyridoxine (201) and its derivatives (202) and (203), and the mechanism by which the loss occurs is found to depend upon the pH of the solution. In neutral solution, the formation of the quinone methide (204) from (201) arises either by excited state proton transfer to the aqueous methanol solvent and loss of OH from the phenoxide ion, or by intramolecular proton transfer and loss of water, while the reaction in alkaline solution involves dehydroxylation from the excited state of the phenoxide ion. 

Thus either 7 or 8 protons are required to convert Cr(VI) to Cr(III) in acidic solution reactions. In alkaline solution (Eq. 2) water is required for protonation of the chromate 0X0 groups. 

Mader, P. M. (1958) Kinetics of the hydrogen peroxide-sulfite reaction in alkaline solution. 

Note that both procedures lead to equations containing fT ions. For reactions in alkaline solutions, it is as well to eliminate these by adding nOW ions to each side of the equation, where n is the number of iT ions. You can then replace lT + OFT on one side of the equation by nH20, leaving nOH on the other side. 

Chloroanthraquinone is especially useful as a base material for the production of 2-aminoanthraquinone, from which the vat dye indanthrene (Vat Blue 4) is produced by a method discovered by Rene Bohn in 1901, involving a reaction in alkaline solution with atmospheric oxygen in the presence of potassium nitrate at 150 to 200 °C. At higher temperatures and using antimony-(V)-chloride or aluminum chloride, flavanthrone (Vat Yellow 1) is obtained this is nowadays produced from l-chloro-2-aminoanthraquinone and PA. 

Basic solution For reactions in alkaline solutions, first balance as though the reaction were in an acidic solution, using Steps 1-3. Then add as many OH ions to each side of the equation as there are ions in the equation. Now combine the and OH" ions into water (for example, 4 and 4 OH" give 4H2O). Rewrite the equation, canceling equal numbers of water molecules that appear on opposite sides of the equation. 

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