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Methyl salicylate, hydrolysis

This compound can be considered as a derivative of the hydrolysis product, [(H20)3Be(0H)Be(H20)3]3+, in which the bidentate 3-methyl-salicylate ligands each replace two water molecules, the other two water molecules being replaced by a carbonate ion bridging between two beryllium atoms. Similar carbonate bridges have been proposed previously (132). [Pg.152]

Figure 11.21—Isobestic point. Alkaline hydrolysis of methyl salicylate at 25 C. Superposition of the successive spectra recorded between 280 and 350 nm at 10 min intervals. Figure 11.21—Isobestic point. Alkaline hydrolysis of methyl salicylate at 25 C. Superposition of the successive spectra recorded between 280 and 350 nm at 10 min intervals.
Wintergreen Gaultheria procumbens (Ericacae) or Betula lenta (Betulaceae) leaves bark 0.7-1.5 0.2-0.6 methyl salicylate (98%) flavour, antiseptic, antirheumatic prior to distillation, plant material is macerated with water to allow enzymic hydrolysis of glycosides methyl salicylate is now produced synthetically... [Pg.140]

Partial hydrolysis and esterification. Aryl esters are hydrolyzed in the presence of alkyl esters (e.g., methyl salicylate from the 6>-benzoyl derivative), and esters of o-dihydroxyarenes undergo partial hydrolysis. " Transacetylation from vinyl acetate to hydroxymethylphenols occurs at the primary alcohol sites. ... [Pg.246]

Methyl o-iodobenzoate is converted under these conditions (equation 11) into methyl salicylate (main product) and dimethyl diphenate (minor product). If the cuprous salt is replaced by the cupric salt, hydrolysis is essentially the only reaction (equation III). If ammonium tetrafluoroborate is added, methyl benzoate is the only product. [Pg.132]

The salicylate compounds used topically share with aspirin the common metabolic breakdown product, free salicylate (see section on aspirin earlier in this text), which is primarily responsible for the toxicity observed. On average, 12-20% of the dose of methyl salicylate is absorbed through the skin. Methyl salicylate is readily hydrolyzed to salicylate, although some methyl salicylate is found in blood. Some unchanged methyl salicylate is excreted in urine as hydrolysis is relatively slow in humans. [Pg.410]

In studies in aqueous dioxane, kinetic evidence has been obtained for an oxydian-ionic tetrahedral intermediate in the alkaline hydrolysis of methyl salicylate (20). ... [Pg.55]

Gatterman reaction ORG CH em 1. Reaction of a phenol or phenol ester, and hydrogen chloride or hydrogen cyanide, i n the presence of a metallic chloride such as aluminum chloride to form, after hydrolysis, an aldehyde. 2. Reaction of an aqueous ethanolic solution of diazonium salts with precipitated copper powder or other reducing agent to form diaryl compounds. gad-3r-man re,ak-sh3n) gaultheria oil See methyl salicylate. g6l thir-e-3, 6il)... [Pg.164]

Being phenolic in nature, methyl salicylate may be extracted from solvent solution by aqueous potassium hydroxide, practically no hydrolysis occurring in the cold if the alkali solution is weak. Other methods of determination can be more advantageously discussed in the analysis of the preparations containing methyl salicylate, which are described below. [Pg.430]

For routine control, it has been found that hydrolysis in dilute ethanol does not appreciably saponify the fats and a close approximation of the methyl salicylate content is possible ... [Pg.431]

The method of determining phenols based upon coupling with 4-amino-phenazone (see Phenol p. 514) has been applied to the determination of methyl salicylate in ointments by Johnson and Savidge. Because of the possibility of hydrolysis of methyl salicylate to the free acid, which gives no reaction (see Note below under Non-Staining Ointment of Iodine), it has not been possible to quote an E(1 per cent, 1 cm) value for the final solution and calculations should always be made from a standard or a calibration curve prepared at the same time as the assay is being carried out. The method for Ointment of Methyl Salicylate, B.P.C., and Compound Ointment of Methyl Salicylate, B.P.C., is as follows ... [Pg.432]

To decide the mechanism of hydrolysis of the ionized and unionized forms of aspirin and monosubstituted aspirins is more difficult because these lead to no incorporation of label into the product salicylic acid when reaction is carried out in 0-enriched water, and there is no formation of the methyl salicylate when reaction is carried out in aqueous methanol [77]. Therefore either the reaction does not proceed via a mixed anhydride or this anhydride reacts exclusively by attack at the acetyl group. [Pg.365]

Salicylic acid (from the Latin Sahx meaning willow tree) is a biosynthesized, organic, beta hydroxy acid that is often used. Sodium salicylate is converted by treating sodium phenolate (the sodium salt of phenol) with carbon dioxide at high pressure and temperature. Acidification of the product with sulfuric acid gives salicylic acid. Alternatively, it can be prepared by the hydrolysis of Aspirin (acetylsahcyhc acid) or Oil of Wintergreen (methyl salicylate) with a strong acid or base. [Pg.12]

Khan, M.N. Effects of anionic micelles on the intramolecular general base-catalyzed hydrolysis of phenyl and methyl salicylates. J. Mol. Gated. A Ghent. 1995, 102, 93-101. [Pg.70]

Khan, M.N., Olagbemiro, T.O. The kinetics and mechanism of hydrolysis of methyl salicylate under highly alkaline medium. J. Org. Chem. 1982, 47(19), 3695-3699. [Pg.198]

The rates of hydrolysis of phenyl and methyl salicylates became independent of [HO ] within the [HOi range of 0.002 to 0.070 M in the absence of micelles. The values of ionization constants, K, for phenyl salicylate and methyl salicylate in water solvent are 5.67 x 10 ° M and 2.48 x 10 ° M, respectively. Thus, within the [HO ] range of - 0.002 to 0.070 M, both phenyl and methyl salicylates exist in fully ionized forms. The pH-independent rate of hydrolysis of salicylate esters involve ionized salicylate ester and H2O as the reactants. Intramolecular general base catalysis has been shown to occur in the aminolysis of ionized phenyl salicylate in both aqueous pseudophase and micellar pseudophase of SDS. - The brief reaction scheme for hydrolysis or alkanolysis of salicylate ester or any substrate containing an easily ionizable proton in the presence of micelles, D , may be given in terms of PP model of micelle as depicted in 8cheme 4.2... [Pg.272]

Unlike the effects of the concentration of SDS micelles on k bs ( 900 to 300% decrease) for hydrolysis of PS , the values of ko s for hydrolysis of ionized methyl salicylate (MS ) decreased only slightly (-25%) with the increase in [SDSJt from 0.0 to 0.4 M as evident from the observed results summarized in Table 4.2. These results could not fit to Equation 4.3 apparently owing to extremely low decrease in kobs within the [SDS lx range covered in the study. However, these data showed statistically good fit to Equation 4.6 (as evident from data shown in Table 4.2), which is derived from Equation 4.3 with condition k fivi Ks pp [D ] k fw . [Pg.274]

NSAIDs) has been reported [36]. As shown in Table 8.3, the hydrolysis of the methyl esters in human plasma proceeds far too slowly to be of therapeutic interest, with tm values ranging from ca. 5 to 150 h. In contrast, the carbamoylmethyl benzoates are hydrolyzed very rapidly (perhaps too rapidly ) with tm values in the order of minutes. But Table 8.3 also illustrates another important point, namely the marked influence of the acyl moiety on the rate of hydrolysis, with a more than 500-fold difference between the smallest and the largest acid (salicylic acid and sulindac, respectively). [Pg.447]

The case of aspirin in Table 8.3 is of special interest. Indeed, its acetyl ester group is particularly labile to enzymatic and nonenzymatic hydrolysis (see Sect. 7.4), and the reaction is even faster when the carboxy group is neutralized by esterification. A true ester prodrug of acetylsalicylic acid must fulfill the condition that its hydrolysis liberates aspirin rather than a prodrug of salicylic acid. An investigation of several aspirin prodrugs confirmed the interest of carbamoylmethyl esters and showed the (ATV-diethylcarbamoyl)methyl ester (Table 8.3) to liberate the highest proportion (ca. 60%) of aspirin [37], In... [Pg.448]

Suitably substituted acetals have been shown to hydrolyse rapidly by a mechanism that involves intramolecular general acid catalysis similar to that proposed for Glu-35 in (34), The largest effects have been found for acetals with the salicylate ion as the leaving group. For example, the spontaneous hydrolysis (35) of 2-methoxymethoxybenzoic acid [73] occurs 300-fold more rapidly than the same reaction of 4-methoxymethoxybenzoic acid [74] and ca. 600-fold more rapidly than the reaction of 2-methoxymethoxybenzoic acid methyl ester [75] (Capon et al, 1969 Dunn and Bruice, 1970). The... [Pg.346]

The indomethacin hydrolysis product 2-methyl-5-methoxy indole acetic acid fluoresces at 385 nm after excitation at 300 nm in 0.1N NaOH,(41) and at 387 nm after excitation at 312 nm in pH 11.6 buffer(42). The latter procedure claimed a threefold increase in detectability. Neither method distinguishes indomethacin from salicylates. Clinical studies employing subjects administered aspirin must use a separation prior to fluorescence analysis. Without adequate separation the indole metabolites as well as salicylate, produce a positive assay bias. [Pg.229]


See other pages where Methyl salicylate, hydrolysis is mentioned: [Pg.184]    [Pg.164]    [Pg.62]    [Pg.26]    [Pg.259]    [Pg.684]    [Pg.513]    [Pg.275]    [Pg.376]    [Pg.275]    [Pg.397]    [Pg.29]    [Pg.128]    [Pg.44]    [Pg.2]    [Pg.397]    [Pg.43]    [Pg.68]    [Pg.43]    [Pg.68]    [Pg.207]    [Pg.29]   
See also in sourсe #XX -- [ Pg.266 , Pg.267 ]




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