Strongly acidic or basic conditions

Indole is a neutral compound but can be protonated or deprotonated under strongly acidic or basic conditions, respectively. The piC of the conjugate acid is about —2.4 that of the neutral compound is about 16.7 (1). 

Hydrolysis of Nitriles. The chemical hydrolysis of nitriles to acids takes place only under strong acidic or basic conditions and may be accompanied by formation of unwanted and sometimes toxic by-products. Enzymatic hydrolysis of nitriles by nitrile hydratases, nittilases, and amidases is often advantageous since amides or acids can be produced under very mild conditions and in a stereo- or regioselective manner (114,115). 

Condensation reactions of hydroxymethyl groups on phenolic resoles and amines on melamine take place between pH 5 and 6 (Fig. 7.33). Only selfcondensations of hydroxymethyl substituents occur under strongly acidic or basic conditions. 

Like similarly activated carboxylate esters, these aromatic phosphonate diesters 30 were readily hydrolyzed to GLYH3 in good yield and purity under typical strongly acidic or basic conditions, or in a stepwise fashion under extremely mild conditions via the zwitterionic monoaryl esters 32 (44). Products such as 32 or 33 readily precipitated after a few hours at room temperature from aqueous acetone. 

C <4.7x10 Pa at 20 °C Water 20 mg at 20 °C Readily soluble in polar organic solvents Stable in neutral and weakly basic conditions Unstable in strongly acidic or basic conditions Stable in most of organic solvents such as acetone, acetonitrile and carbon tetrachloride Undergoes hydrolysis to yield methomyl oxime in alkaline solutions... 

In our retro-synthetic analysis, we envisioned the pyrrolidinylethanol side chain could be installed via the Ullmann ether formation or the analogous reachons from the aryl-iodide functional group. The key intermediate 9 (cis) in the Medicinal Chemistry route was not stable under strongly acidic or basic conditions since it was easily isomerized to the thermodynamically more stable trans-isomer 9a via... 

The reduction of conjugated nitroalkenes such as S-nitrostyrenes to oximes provides easy access to a large number of versatile organic intermediates. However, despite their potential utility, many of these methods suffer from the use of strongly acidic or basic conditions, requirement of anhydrous conditions, and incompatibility with halogenated arenes. Eurther, some of the methods are inefficient for the preparation of aldoximes due... 

Esters and amides, on the other hand, require the presence of an acid or base catalysis to react with water. These reactions are not instantaneous but require rather strongly acidic or basic conditions and heat to proceed at a reasonable rate. For example, a typical ester saponification is usually conducted with 10% NaOH in water, and the solution is refluxed until the ester layer disappears. (Most esters are not soluble in water.) This may require from 15 minutes up to several hours of reflux. Similarly, a typical amide hydrolysis is often conducted by refluxing the amide in concentrated hydrochloric acid for a period ranging from 15 minutes up to several hours. Esters and amides are relatively stable to the near-neutral conditions found in living organisms, which is one reason why they are important functional groups in biochemistry. 

As the deposited oxide layer is well mixed, strong interaction between the oxides is expected, leading often to mechanically strong materials, but pretreatment procedures can be hindered. For instance, in the preparation of a metal-based catalyst, a reduced reducibility of the precursor is often encountered, and, as a result, a reduced availability of the catalytically active phase is encountered. Moreover, under strongly acidic or basic conditions, some support materials, e.g., alumina, may be dissolved, as mentioned before. Furthermore, the adhesion of the precipitated layer with the monolith substrate is often a point of concern, especially during drying and heat treatment. 

Coarse 12 34 Coarse gelatinous precipitates useful for analysis under strongly acidic or basic conditions. 

Enol silyl ethers react with aldehydes with a catalytic amount of TBAF to give the aldol silyl ethers in good yields. These reactions generally proceed under very mild conditions and within shorter periods of time than conventional strong acidic or basic conditions. The products from4-f-butyl-l-methyl-2-(trimethylsilyloxy) cyclohexene and benzaldehyde show very good axial selectivity and a little anti-syn selectivity (eq 20). The aldol condensation of ketones and aldehydes can be achieved in one pot when ethyl (trimethylsilyl)acetate is used as a silylation agent with TBAF (eq 21). 

Due to the fact that the compound is a salt, the water solubility of fosetyl-aluminium is extremely high. It is stable towards hydrolysis under neutral conditions and decomposes only under strong acidic or basic conditions or by exposure to strong oxidizing agents. Table 21.3 lists further physicochemical properties [23]. 

It is confusing to have this wealth of esterification methods why are there so many Of course there are no bounds to the ingenuity and skill of organic chemists, but as far as derivatization for chromatography goes, clearly some procedures have been developed in response to particular problems perhaps the acid is sensitive to particular environments (strongly acidic or basic conditions, moisture), or thermolabile or sterically hindered. Other methods may have been chosen for speed, for convenience or for quantitative yield. At this point perhaps some guidance would be helpful. 

The rearrangement of benzil 4 in water at 300-380 °C proceeds under neutral conditions with no added catalyst. The yield of products shows little variation with pH at near neutral conditions, but it increases greatly under more strongly acidic or basic conditions. Hence, it has been shown that the rearrangement in high-temperature water is catalyzed not only by OH but also by H" and by water itself ... 

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