Preparation periodic acid oxidation

In the 1-electron reduction of A1 4-3-ketosteroids (164), various stereoisomers of pinacols are formed according to the pH. The protonized form of the ketosteroid, reduced in acidic solution, gives rise to a pinacol with hydroxyl groups in the a-position. In alkaline media, the unprotonized ketosteroid is reduced with the formation of the isomer with the hydroxyls in the p-position. The structure of the products prepared by controlled potential electrolysis, are supported by the rates of dehydration and periodic acid oxidations. For A4-3-ketosteroids, the difference in the composition of products obtained in acidic and alkaline media is less pronounced. 

The aldehyde (163), which was prepared from 160 by periodic acid oxidation, was further converted into pseudo-a-D-mannopyranose as follows. Dehydration of 163 with mesyl chloride and pyridine, and subsequent reduction with lithium aluminium hydride gave (3S, 4R, 5S)-3,4,5-tris(benzyloxy)-l-cyclohexene-1-methanol (164). Hydroxyla-tion of 164 with diborane and hydrogen peroxide yielded 4,6-di-0-acetyl-l,2,3-tri-0-... 

Poly(isobutylene) dicarboxylic acid was prepared by oxidation of the copolymer of isobutylene with a diene 53,54). The most efficient oxidizing agent was the system KMn04-periodic acid. Oxidation of a copolymer of isobutylene and 2,3-dimethyl-butadiene afforded a polymeric bis-ketone54). 

Although known for almost forty years, and in spite of a total synthesis of its racemate, the stereochemistry of doisynolic acid has remained in doubt. This problem has now been settled by a stepwise chemical conversion (Scheme 23) of 14)5-oestrone methyl ether (339), prepared from natural oestrone (114a), into c/s-doisynolic acid methyl ether (342). Osmium tetroxide oxidation of the enol acetate corresponding to (339) provided 16a-hydroxy-14)S-oestrone methyl ether. Subsequent periodic acid oxidation afforded the lactol (340), which upon treatment with diazomethane gave the aldehydo-ester (341). Electrochemical reduction of the aldehyde (341) afforded a methyl ester which by alkaline hydrolysis provided (-f )-ds-doisynolic acid 3-methyl ether (342), thus defining its complete stereochemistry. ... 

A distant, sulfur analog of l,6-anhydro-2,3,4-trideoxy-j3-D-glt/cero-hexopyranose (26) is (lR,5R)-6,8-dioxa-3-thiabicyclo[3.2.1]octane (241), which was prepared by periodic acid oxidation of levoglucosan (6), followed by reduction of the resulting dialdehyde 100 to diol 242, and by p-toluenesulfonylation to 243, and replacement of the two sulfonic ester groups of 243 with sodium hydrogensulfide.731... 

A procedure for the release of the diacylglycerol moieties from galactosyidiacylglycerols (including sulfoquinovosyidiacylglycerols) has been described, involving periodic acid oxidation in methanol followed by incubation with 1,1-dimethylhydrazine [382]. The diacylglycerols are then converted to UV-absorbing derivatives for separation by means of HPLC [475], but equally it should be possible to prepare TMS or BDMS ethers and use the GC conditions developed for the analysis of the equivalent compounds released from phospholipids (see Section C above). 

HRP-AaHI was prepared with periodic acid oxidization (Nakane et al., 1974). 5 mg HRP and 5 mg AaHI were used. After labelling, HRP-AaHI was separated from HRP and AaHI with Sephadex G-75. The elution solution was 0.02 M PBS and the flow rate was 8 ml/hr. 2.5 ml fractions were collected in each tube. 

These are acids which can be regarded, in respect of their formulae (but not their properties) as hydrates of the hypothetical diiodine heptoxide, liO-j. The acid commonly called periodic acid , I2O7. 5H2O, is written HglO (since the acid is pentabasic) and should strictly be called hexaoxoiodic(VII) acid. It is a weak acid and its salts are hydrolysed in solution. It can be prepared by electrolytic oxidation of iodic(V) acid at low temperatures ... 

Perhalates. Whereas silver perchlorate [7783-93-9] AgClO, and silver periodate [15606-77-6] AglO, are well known, silver perbromate [54494-97-2] AgBrO, has more recendy been described (18). Silver perchlorate is prepared from silver oxide and perchloric acid, or by treating silver sulfate with barium perchlorate. Silver perchlorate is one of the few silver salts that is appreciably soluble in organic solvents such as glycerol, toluene, and chlorobenzene. 

During the preparation of the quaternary oxidant tetraethylammonium iodate from the aqueous reagents, the residue after vacuum evaporation of most of the water exploded, breaking the flask. This was attributed to possible presence of excess periodic acid in the reaction mixture [1]. Further details and precautions to avoid heating the salt, normally stable in storage, are given [2],... 

In homogeneous reactions, the upper limits of concentration are determined by the (limited) solubility of the salts of periodic acid and by the low pH values produced by periodic acid itself. Apart from these considerations, the concentration conditions to be selected are governed by the type of information desired. A very dilute solution having a high oxidant substrate ratio is used in the exploratory or preliminary phase defined earlier (see p. 13), but a more concentrated solution, in which the oxidant is only slightly in excess of the theoretical, is recommended for the preparative phase. 

Other Methods of Preparation.—Ethyl 2-formyl-5-methyl-4-furoate has also been prepared by the oxidation of ethyl 2-(D-ara6ino-tetrahydroxybutyl)-5-methyl-4-furoate by means of periodic acid,8 sodium periodate,19 or minium ( red lead ) in acetic acid.66 It can also be prepared by the oxidation with sodium periodate of ethyl 2-(D-lyzo-tetrahydroxybutyl)-5-methyl-4-furoate,15 of ethyl 2-(D-fftreo-trihydroxy-propyl)-5-methyl-4-furoate,13 of ethyl 2-(o-erythro-trihydroxypropyl)-5-methyl-4-furoate,17 of ethyl 2-(L-eryfAro-trihydroxypropyl)-5-methyl-4-furoate,13 and of ethyl 2-(D-goIado-pentahydroxypentyl)-5-methyl-4-furoate.16... 

Quaternary ammonium periodates, prepared either from periodic acid and the quaternary ammonium hydroxide [21, 22] or by metathesis from sodium periodate and a quaternary ammonium salt [e.g. 23-25], have been used for a range of oxidations at stoichiometric levels in two-phase systems [21-33], The tetra-n-butyl-ammonium and hexadecyltrimethylammonium salts are both highly soluble in organic solvents (considerably less so in water), whereas benzyltriethylammonium periodate has a lower solubility and stability than either salt. 

Recently, we reported that an Fe supported zeolite (FeHY-1) shows high activity for acidic reactions such as toluene disproportionation and resid hydrocracking in the presence of H2S [1,2]. Investigations using electron spin resonance (ESR), Fourier transform infrared spectroscopy (FT-IR), MiJssbauer and transmission electron microscopy (TEM) revealed that superfine ferric oxide cluster interacts with the zeolite framework in the super-cage of Y-type zeolites [3,4]. Furthermore, we reported change in physicochemical properties and catalytic activities for toluene disproportionation during the sample preparation period[5]. It was revealed that the activation of the catalyst was closely related with interaction between the iron cluster and the zeolite framework. In this work, we will report the effect of preparation conditions on the physicochemical properties and activity for toluene disproportionation in the presence of 82. ... 

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