Hydrolysis products of methylated

The hydrolysis products of methylated disaccharides may be separated by p-phenylazobenzoylation followed by chromatographic adsorption, or the methanolysis products of the methylated disaccharides may be separated due to differential water solubilities of the p-phenylazo-benzoates.110... 

Schwarz and Knauff (64) approached the problem of the poly-silicic acids quite differently, by preparing linear partial hydrolysis products of methyl silicate,... 

This sugar was isolated as its monohydrate from the hydrolysis products of methylated yeast mannan and its structure proved by Haworth, Heath and Peat.23 Methylation of the methyl glycoside gave the crystalline methyl 2,3,4,6-tetramethyl-a-D-mannopyranoside, indicating a pyranose structure. It seemed likely that the compound was the monohydrate of 2,4,6-trimethyl-D-mannose, as the 2,3,4- and 2,3,6-isomers were known as sirups that did not form hydrates, and the crystalline... 

This sugar has not so far been synthesized. A monomethyl-D-galactose, isolated from the hydrolysis products of methylated damson gum, is considered by Hirst and Jones,28 on good evidence, to be the... 

This sugar has not been prepared synthetically. It is, however, a frequent constituent of the hydrolysis products of methylated polysaccharides containing galactose radicals, for example plant gums26 and the so-called galactogen of the albumin glands of the snail Helix pomatia.27,28... 

The first synthesis of 2,3,4-trimethyl-D-galactose, which had previously been isolated from the hydrolysis products of methylated galac-tosans, was achieved by McCreath and F. Smith.20 1,6-Anhydro-D-galactopyranose, treated with dimethyl sulphate and alkali, underwent easy methylation and the resulting crystalline 2,3,4-trimethyl-l,6-anhydro-D-galactopyranose was conveniently hydrolyzed to the free sugar hydrate. 

Jeevaratnam, K., Sugendran, K., Vaidyanathan, C.S. (1992a). Influence of methylamine and N,N -dimethylurea, the hydrolysis products of methyl isocyanate, on its systemic toxicity. J. Appl. Toxicol. 13 15-18. 

The linkage of the hexosamines to 2-deoxystreptamine was indicated to be at positions 4 and 6 by the periodate oxidation of kanamycin, in which only the 2-deoxystreptamine survived. Conclusive evidence was afforded by the isolation of di-A -acetyl-2-deoxy-5-0-methyl-streptamine from the hydrolysis products of methylated tetra-Af-acetylkanamycin. In addition, the isolation, from this hydrolyzate, of 3-acetamido-3-deoxy-2,4,6-tri-0-methyl-a-D-glucose demonstrated that kanosamine is present as the pyranoid form in kanamycin. Earlier evidence that both hexosamines are present in kanamycin as pyranoid forms had been obtained from periodate-oxidation studies on tetra-iV-acetylkanamycin. At pH 2.5, this derivative rapidly consumes 2 moles of periodate per mole, with the formation of 1 mole of formic acid and no formaldehyde. Examination by paper chromatography of the products of hydrolysis of the reaction mixture by strong acid showed the presence of 2-deoxystreptamine and kanosamine but not of 6-amino-6-deoxy-D-glucose. 

TABLE 2. Hydrolysis products of methylated, original and degraded cell wall glucan of Pyricularia oryzae.(9)... 

TABLE k. Molar ratios of the hydrolysis products of methylated original, acid degraded, and a-mannanase digested proteoheteroglycan from P. oryzae. 

Trimethyl aluminum and propylene oxide form a mixture of 2-methyl-1-propanol and 2-butanol (105). Triethyl aluminum yields products of 2-methyl-1-butanol and 2-pentanol (106). The ratio of products is determined by the ratio of reactants. Hydrolysis of the products of methyl aluminum dichloride and propylene oxide results ia 2-methylpropeae and 2-butene, with elimination of methane (105). Numerous other nucleophilic (107) and electrophilic (108) reactions of propylene oxide have been described ia the Hterature. 

Thermal chlorination of methane was first put on an industrial scale by Hoechst in Germany in 1923. At that time, high pressure methanol synthesis from hydrogen and carbon monoxide provided a new source of methanol for production of methyl chloride by reaction with hydrogen chloride. Prior to 1914 attempts were made to estabHsh an industrial process for methanol by hydrolysis of methyl chloride obtained by chlorinating methane. 

The isolation of 2,3-dimethyl-D-glucose from the hydrolysis products of certain methylated polysaccharides has been an important factor in assigning structures to these polysaccharides. From trimethyl-starch it has been recovered in about 3% yield, together with 2,3,4,6-tetra-methyl- and 2,3,6-trimethyl-D-glucopyranose, and arises from the points of linkage of the repeating chains of the amylopectin component.67,69,70 From a dimethyl-starch the yield is considerably higher (75%).71 Other sources are the methylated capsular polysaccharide of Rhizobium radici-... 

The naturally-occurring 1,6-linked glucose polymers furnish other sources of 2,3,4-trimethyl-D-glucose, which has been isolated from the hydrolysis products of the methyl ethers of gentiobiose,112 118 melibiose,114 raffmose106 116 and dextran.78 74,116... 

The dimethyl derivative of isomannide was synthesized by Wiggins as follows. l,6-Dichloro-l,6-didesoxy-3,4-isopropylidene-D-mannitol was converted i nto 1,6-dichloro-l, 6-didesoxy-2,5-dimethyl-3,4-isopr opylidene-D-mannitol (LVI). This on mild acid hydrolysis gave 1,6-dichloro-l,6-didesoxy-2,5-dimethyl-D-mannitol (LVII) which with cold sodium methoxide furnished 2,5-dimethyl-l,4 3,6-dianhydro-D-mannitol (LVIII), identical with the product of methylation of isomannide itself. Further... 

Soil. Harvey and Pease (1973) reported that methomyl dissipated rapidly in fine sand and loamy sand soils. One month following application to a Delaware soil, 1.8% of the applied dosage was recovered and after 1 yr, methomyl was not detected. The hydrolysis product (5-methyl A/ hydroxythioacetimidate) and a trace mixture of very polar compounds were the intermediate degradation compounds before forming the principal end product, carbon dioxide. 

Xyloisosaccharinic acid [2,4-dihydroxy-2-(hydroxymethyl)butanoic acid] is one of the major, alkaline-degradation products of wood xylan, in particular, that of birch. The disaccharide, 2-O-D-xylopyranosyl-L-arabinose, which was isolated as a hydrolysis product of corn-cob hemicellulose, is readily degraded at 100° in 15 mM Ca(OH)2 to acidic products, primarily saccharinic acids. Xylan oligosaccharides from corn-cob hemicellulose produced 2,4-dihydroxy-2-(hydroxymethyl)buta-noic acid when exposed to 0.02 M Ca(OH)2 at 25°. However, it was noted that the xylan, itself, was stable at 100° in Af NaOH. The major acidic component of the hemicellulose fraction of slash pine Pinus el-liotti) after acid hydrolysis was identified as 4-O-methyl-D-glucuronic... 

Methanol, a side product of methyl chloride hydrolysis, can be recovered and reused. In addition, recovered water is recycled. The products are formulated on site as solutions and are shipped in 1 to 30 gallon containers. 

Figure 2. Hydrolysis products of beechwood O-acetylglucuronoxylan (Fig. 2a), beechwood glucuronoxylan (Fig. 2b), and wheat straw arabinoxylan (Fig. 2c), as analyzed by gel permeation chromatography. The hydrolysis was carried out at pH 5 at 45°C for 24 h using 10.000 nkat of the 20 kDa xylanase of T. reesei. X = xylose X2 = xylobiose Xmga — 4-O-methyl-glucuronosyl substituted xylo-oligosaccharides X = xylo-oligosaccharides DP > 20.

The biocidal activity of the thiadiazine (12) is probably related to the production of methyl isocyanate inside the cell by hydrolysis (equation 7). Isocyanates are known to have fungicidal properties (B-69MH1502), thought to be due to their reaction with sulfhydryl groups to form dithiocarbamates. The formation of these last mentioned compounds, by ring cleavage, might also explain the activity of 2-mercaptobenzothiazole (16). 

Dimethyl-D-mannose has been isolated from the hydrolysis products of the methylated galactomannans from carob seed gum14-18 and from guar gum,16 17 and also from mannocarolose,8t 18 a polysaccharide synthesized by Penicillium charlesii G. Smith. The synthesis of this sugar, which has not been obtained crystalline, has been accom-... 

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