Hydrolysis in aqueous alkali

Benzo[g]cycl[3.2.2]azines or pyrrolizino[3,4,5- 3]isoquinolines, for example, 366, are similarly obtained by cycloaddition of DMAD to pyrrolo[2,l- ]isoquinolines <1985CPB3038>, and l-aza-benzo[ ]cycl[3.2.2]azines are prepared by cycloaddition of DMAD to imidazo[2,l- ]iso-quinolines <1985H(23)2531> (Scheme 102). In all of the above cases, as with the simpler cyclazines, the ester functions are removable by hydrolysis in aqueous alkali followed by... 

Water Retention of Hydrolyzed Samples. The water retention of the AN-grafted samples after hydrolysis in aqueous alkali were determined using three different methods ... 

Similarly, treatment of the anthranilic acid derivative (248) with nitrous acid gave the cyclic product 249 which underwent hydrolysis in aqueous alkali to afford o-azidobenzoic acid 1,2-Diacetylhydra-... 

PETP flakes produced from used soft drinks bottles were subjected to alkaline hydrolysis in aqueous sodium hydroxide. A phase transfer catalyst (trioctylmethylammonium bromide) was used to enable the depolymerisation reaction to take place at room temperature and under mild conditions. The effects of temperature, alkali concentration, PETP particle size, PETP concentration and catalyst to PETP ratio on the reaction kinetics were studied. The disodium terephthalate produced was treated with sulphuric to give terephthalic acid of high purity. A simple theoretical model was developed to describe the hydrolysis rate. 17 refs. 

Figure 2.4 Schematic representation of silicon hydrolysis from the zeolite framework in aqueous alkali hydroxide solution.

Silver(ll) oxide, present on a silver anode in aqueous alkali, will also cany out the oxidation of primary amines to nitriles. Oxidation of the intermediate imine at the silver anode is however relatively slow so that hydrolysis to the aldehyde becomes an important side reaction [97], a-Amino acids give nitriles in good yields at the silver(li) oxide electrode. 

Acids, (a) Carboxylic Liquid carboxylic acids are first freed from neutral and basic impurities by dissolving them in aqueous alkali and extracting with ethyl ether. (The pH of the solution should be at least three units above the PKa of the acid). The aqueous phase is then acidified to a pH at least three units below the pK of the acid and again extracted with ether. The extract is dried with magnesium sulphate or sodium sulphate and the ether is distilled off. The acid is fractionally distilled through an efficient column. It can be further purified by conversion to its methyl or ethyl ester (see p. 52) which is then fractionally distilled. Hydrolysis yields the original acid which is again purified as above. 

Insoluble in water, but readily soluble in acid or alkali soluble in benzene and ether. Hydrolysis in aqueous and alkaline solutions leads to replacement of Cl atoms by OH forming the hydroxy form.2... 

Dimethylpyrazole has been prepared from acetylacetone and hydrazine hydrate in ethanol3 or hydrazine sulfate in aqueous alkali.4 6 The latter method is preferred, because the reaction with hydrazine hydrate is sometimes violent.3 4 3,5-Dimethyl-pyrazole has also been prepared by hydrolysis and decarboxylation of the 1-carbamido- or 1-carboxamidine derivatives, obtained by reaction of semicarbazide 7 or aminoguanidine 8 with acetylacetone. 

The anomalous character of ammonium hydroxide is the cause of another marked difference between the salts of ammonium and those of the alkali-metals, manifested in a much greater degree of hydrolysis in aqueous solution. When slightly warmed, a previously neutral solution of an ammonium salt reddens litmus. When the ammonia is in combination with a non-volatile acid, boiling expels it, and ultimately an acidic reaction develops in the solution.5 The velocity of the action... 

A kinetic study of the effect of water on the hydrolysis of (173) established the existence of two reaction pathways leading to the carbonyl derivatives, depending on water concentration. The unsatisfactory results observed in many instances led to modifications of the hydrolysis conditions. The supposed limitation of the Nef reaction due to steric hindrance is probably a result of the low solubility of nitroalkanes in aqueous alkali, as demonstrated by the success of the reaction if THF-H20," alcoholic sodium hydroxide" or alkoxide" is used. Silica gel" ° as a reaction medium is of great advantage when the use of organic solvents is undesirable. A two-layer method represents an improvement for the conversion of aromatic nitroalkanes. ... 

In common with other penicillins, amoxicillin hydrolyses in aqueous alkali to a penicilloic acid, V. This has been isolated and characterised as the monosodium salt [42], which was subsequently shown [43] to have retained the 5R configuration of the parent penicillin. Epimerisation of the penicilloic acid in aqueous solution has been studied [43,44] and shown [43] to occur at C5, rather than at C6 as stated, without evidence, in [44], The penicilloic acid can also be obtained by hydrolysis with P-lactamases. 

Schiff bases are readily hydrolyzed on heating with acids however, occasionally, due to their insolubility in acidic medium, hydrolysis can be carried out only in aqueous alkali (87KGS836). 

Nitriles are easily reduced by Ni—A1 alloy, to the corresponding primary amine in aqueous alkali, and to the aldehyde in aqueous formic acid solution. Reductive hydrolysis may lead to the carbinol after furAer hydrogenation of the aldehydic group, as... 

On the other hand, A-tosylated aza-crowns were formed in good yields (50-94%) from the reaction of the bis-sulfonamides with dibromides or di-tosylates in aqueous alkali-toluene or benzene mixtures in the presence of quaternary ammonium salt phase-transfer catalysts. Some cyclizations did not depend on alkali concentration, but for the tri- or tetraaza-crowns, 50% alkali solutions were preferred. In the synthesis of A,jV -ditosyldiaza-18-crown-6 via the interaction of the bis-sulfonamide with a dibromide, dichloride, diiodide, or ditosylate using 50% aqueous sodium hydroxide-toluene or benzene solution in the phase-transfer reaction, the cyclization rate varied according to the leaving group, Br > OTs > I > Cl. In dilute alkaline solution (7.5%), the diiodide was more reactive than the ditosylate. This could be a result of the greater activity of water in the solution so that hydrolysis of the tosylate is more rapid and, therefore, there would be less tosylate to react with the amide (Bogatskii et al., 1984 Lukyanenko et al., 1987, 1988). 

PROBABLE FATE photolysis occurs in aqueous alkali, photolysis may occur near surface of waters and in atmosphere oxidation probably cannot compete with biodegradation, complete oxidation by Pseudomonas isolated from activated sludge hydrolysis not an important process volatilization too slow to be important, evaporation half-life 73 days sorption slight potential for adsorption by lipophilic materials, may adsorb to sediments if released in water biological processes no bioaccumulation more resistant to biodegradation than phenol, complete removal by biodegradation in 13-36 days in river waters other reactions/interactions chlorination of water eould further chlorinate the compound... 

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