Hydrolytic agents

The glucosides are compounds, which, under the influence of hydrolytic agents are decomposed into glucose or an allied aldose or ketose, and one or more other bodies, which, in the cases under consideration, form constituents of essential oils. The hydrolytic agents which bring about these changes are soluble ferments, such as diastases, enzymes and similar... 

The dehydration which leads to the formation of nitriles and the action of hypohalides on amides are dealt with in the following preparations. The amino-group of the amides, as distinguished from that of the amines, is more or less easily removed by hydrolytic agents, acids being re-formed. For the cause of this difference in behaviour compare the explanation given on p. 128. 

Sonochemical routes also have been used to produce electroactive NPs. For example, metal hydroxides containing Ni(II), Co(II) and mixtures of both have been prepared from the appropriate metal nitrate salts using ammonium hydroxide as the hydrolytic agent [33,34]. This route produces metal-hydroxide NPs with diameters in the range of 2-10 nm. This method has been extensively applied in the synthesis of a wide variety of materials, including nanomaterials [35]. 

Sen SE, Roach SL, Boggs JK, Ewing GJ, Magrath J (1997) Ferric chloride hexahydrate a mild hydrolytic agent for the deprotection of acetals. J Org Chem 62 6684—6686... 

A. C. Classen used sulfur dioxide as the hydrolytic agent, and experimental plants were built in France to determine the suitability of this process. In 1903 patent rights were sold to an American company, which built an experimental plant at Highland Park, Illinois. Later this company erected a plant at Hattiesburg, Mississippi, to operate on sawmill waste of longleaf pine. Because of mechanical difficulties and a failure to understand the principles involved, the plant closed. Another plant was built at Port Hadlock, Washington, which used the sulfur dioxide process, but it, too, failed after a short time. 

The stability of cyclic ethers toward hydrolytic agents is largely a function of the size of the ring and, hence of the internal strain. Thus, whereas the oxiranes (epoxides) are particularly sensitive to these reagents,95,96 the oxetanes are relatively more stable.97 Oxolanes of the tetrahydrofuranol type seem, in particular, little affected by... 

N 34.14% crysts (from w), mp 109.8-12.0° was first prepd by Bachmann in poor yield by hydrolysis of propylene dlnitrourethane ( Ref 2), and in 6l% yield by Bloomquist using dry NH3 as the hydrolytic agent (Ref 3) McKay Manchester (Ref 4) prepd it by hydrolysis of l,3-dinitro-4-rnethy 1-1,3-diazacy clopentane Bloomquist (Ref 3) reported the following props ... 

By use of benzene sulphonic acid or phosphoric acid. When the ester yields on hydrolysis products which become coloured in presence of alkali and air, Method 1 is inapplicable. If the acid produced on hydrolysis is volatile in steam, benzene sulphonic or phosphoric acid may be used as hydrolytic agent, and the acid (from the ester) after separation by steam distillation is titrated with standard alkali. (See Estimation of Acetyl Group, p. 479.)... 

Typically, the raw material for cellulose processing is a lignin-hemicellulose-cellulose (LHC) complex that is not very amenable to hydrolysis. Various pretreatments involving size reduction, separation of constituents of the complex, and processes to increase the accessibility of cellulose to hydrolytic agents may be required. These activities convert a relatively intractable raw material into a cellulosic substrate. 

Recent studies of the Raman spectra of Celluloses I, II, and IV have indicated that the different polymorphic forms involve two basically different molecular conformations in addition to the differences in crystalline packing (7,8,9). The conformation variations suggested by the Raman spectra are such that they could play an important role in determining the susceptibility of glycosidic linkages to attack by hydrolytic agents. The questions raised by this possibility will be addressed in this chapter. 

The present Section is mainly concerned with differences of stability between the two classes of derivatives and any variations within each class. Their stability toward hydrolytic agents has frequently been examined, and, for the thiocarbonates, the thermal stability has also received attention. These studies have, in general, been neither exhaustive nor quantitative, and comparative data are directly available for certain cellulose derivatives only. The progressive replacement of the oxygen atoms in a neutral carbonic ester by sulfur appears to lead to a decrease in the sensitivity to alkali and an increase in the sensitivity toward acids, water, and heat. As expected, the acid esters are less stable than their neutral analogs toward the last-named agents. 

Selective cleavage still makes use of intramolecular assistance, but departs from conventional nucleophilic hydrolytic agents in favor of electrophilic agents or groups. The roles in this case have been reversed. In hydrolysis the amide carbonyl (L) serves as attractant (LI) for nucleophilic groups in the selective cleavage the negative end of the carbonyl... 

The first experiments on the acid hydrolysis of proteins were performed by Braconnot in 1820. Over the next 100 years studies by other workers with a variety of hydrolytic agents led to major advances in our knowledge of proteins, including the identification of the amino acid constituents of proteins and the development of the polypeptide concept of protein structure. These studies are now, for the most part, of historical interest, and a detailed insight into protein hydrolysis has come only in the past 20 to 30 years. This is largely the result of three significant developments ... 

It can be concluded that the bacterial proteinases can be applied to many proplems where extensive enzymatic proteolysis is required. Because of their wide substrate specificity, they are not useful for producing one of the major sets of peptides which are required to provide overlapping sequences within large polypeptides or proteins. On the other hand, where structural studies of small peptides require extensive cleavage at a variety of bonds, the bacterial proteinases are excellent hydrolytic agents. The products of proteinase action are often quite analogous to the products... 

Diazidocarbonylpyrazine refluxed in benzene gave 2,5-diisocyanatopyrazine (50) (which was stable to hydrolytic agents) (1172). 5-Azidocarbonyl-2,3-bis(fur-2 -yl)pyrazine reacted with amines to afford the corresponding urea derivatives (1163). 

Schneider and Wrede, using potassium methoxide as the hydrolytic agent in place of myrosin, isolated thioglucose and merosinigrin. The latter results by closure of a new ring, after removal of the sulfuric acid group. 

In the early attempts to identify the nitrogenous bases of desoxy-ribosenucleic acid, some confusion arose for two reasons. At first, the products obtained by hydrolysis of nucleoprotein were studied, and there was no assurance that any particular base came from the nucleic acid rather than from the protein. Then, when the nucleic acid itself became available, the hydrolytic agents at first employed were sufficiently drastic to cause some deamination of the amino-purines (with the production of some xanthine and hypoxanthine) and some demethylation of thymine to uracil. In 1874, Piccard isolated guanine (and h3T>oxanthine) from sperm nuclein. Kossel and Neumann discovered in the hydrolysate of thymus nucleic acid two new pyrimidine bases which they named thy-mine and cytosine but they assigned incorrect empirical formulas to them. In 1894, they correctly described thymine as CsHgOjNs, but cytosine was not purified and characterized till much later. " " Levene now analyzed a series of nucleic acids from a variety of sources and found " that they all contained guanine and adenine. By mild hydrolysis of thymus nucleic acid, Steudel obtained guanine and adenine as the sole purine bases and demonstrated that they occur in equi-molecular proportions. Levene and Mandel confirmed this result and showed that the two purine bases and the two pyrimidine bases (thymine and cytosine) all occur in thymus nucleic acid in equimolecular proportions. 

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