Periodate oxidation, diols

In theory, periodate oxidation could have given a clear-cut answer as to the composition of the isomeric mixture of deoxy ribose phosphates. The 4-phosphate (73), devoid of vicinal diol groups, should be resistant to periodate the 3-phosphate (74) should reduce one and only one molar equivalent of the oxidant and yield one molar equivalent of both formaldehyde and the phosphorylated dialdehyde (75), whereas the 5-phosphate (76) could be expected to reduce one molar equivalent of periodate relatively rapidly, followed by a slower overoxidation reaction owing to the oxidation of malonaldehyde, formed as a result of the glycol cleavage. 

The appearance of free iodine during the periodate oxidation of compounds having an active hydrogen atom (27) or an ene-diol structure (1,39) has frequently been observed, and this implies that further reduction of iodate, formed from periodate during the main reaction, takes place. It has, in fact, been shown that, in acid solution, iodate is fairly readily reduced by such compounds as triose reductone (27), dihydfoxy-fumaric (39), and tartronic (32) acids. 

The oxidative cleavage of v/c-diols to give two carbonyl functions (Eq. 5.3) by periodates was first observed by Malaprade and has since been widely applied to the carbohydrate area.50 Since both the reagent sodium periodate and the carbohydrate substrate are water soluble, the reaction is usually carried out in aqueous media.51 The reaction has been applied to polysaccharides such as starch.52 The periodate oxidations of sodium alginate in water as well as a dispersion in 1 1 ethanol-water mixture have been compared.53 Because sodium alginate forms a highly viscous solution, the oxidation was observed to be more extensive in ethanol-water. 

The effect of pH on the periodate oxidation of seven anilines has been investigated. " The kinetics of periodate oxidation of aromatic amines have been studied. " - " Periodate oxidation of oxalic acid is catalysed by Mn(II). " The reaction of ethane-1,2-diol with periodate has been investigated under a variety of conditions and the results compared with those of earlier work and analogous studies on pinacol. " The 104 ion is the primary reactant, with H5IO6 as a secondary reactant the reverse is true for pinacol. The complex observed in previous work is shown not to be an intermediate, but rather to deactivate the reactants. 

Reduction of the furan (152) with sodium borohydride gave diol 154 and its cyclization (P2SJ/CS2) formed 19% of sulfide (155). Periodate oxidation of 155 gave (92%) the corresponding sulfoxide (156). The latter reacted with dimethyl acetylenedicarboxylate forming the adduct 157 (70%) the formation of 157 is evidence of the presence of the thieno[3,4-c]furan system (158) as an intermediate. Cyclization of diketone 153 in the presence of phosphorus pentasulfide proceeds M. P. Cava and M. A. Sprecker, J. Amer. Chem. Soc. 94, 6214 (1972). 

The sensitivity to periodate of Ser and Thr is thousands of times greater than that of the better known periodate oxidation of 1,2-cis-diols, for example in the sugars of glycoproteins.19 This means that the concentration of reagent can be kept very low, in only small excess over the l-amino-2-alcohol, and the reaction time kept short (3 to 10 min). It is, thus, usually possible to avoid oxidative attack of the side chains of Met, Trp, and His, but some risk of... 

The configuration of the products was established by periodate oxidation of the D compound, and reduction of the resulting dialdehyde to an optically active diol whose sign and magnitude of optical rotation ([a] ° +2.5° in water) correspond to that of the diol ([a]n° 46.8° in water) obtained by similar treatment of methyl a-L-arabinopyrano-side. The bis(p-nitrobenzoates) of the two diols exhibited similar relationships. Hence, it appears likely that the configuration at C-2 of the anhydride is the same as that at C-l of the L-arabinoside. The cis relationship of the hydroxyl groups was retained from the arabinal started with. 

The treatment of an alkene by 5yn-hydroxylation, followed by periodic acid (HIO4) cleavage, is an alternative to the ozonolysis, followed by reductive work-up. 5yn-diols are oxidized to aldehydes and ketones by periodic acid (HIO4). This oxidation reaction divides the reactant into two pieces, thus it is called an oxidative cleavage. 

Likewise, polycyclic derivatives of bicyclo[4.2.0]octane-l,6-diol were oxidized by periodate to give derivatives of cyclooctane-1,4-dione.37,157... 

Bicyclo[5.2.0]nonane-l,7-diol was oxidized by potassium periodate in water at room temperature to yield cyclononane-1,4-dione (6). 56... 

Buchanan, Dekker and Long used periodate oxidation, followed either by Schiff s reagent (for cis-diols) or potassium iodide (for triols). The test is general for non-reducing carbohydrates having the necessary configuration of hydroxyls. Lead tetraacetate oxidation requires no further reagent to reveal the spot.66... 

Periodate oxidation of the cw-diol in lythrancine 101 and Hofmann degradation of lythrancine 101,102, and 103 were tried but all attempts were unsuccessful (55). 

Periodate oxidation. Aldehyde groups can be easily introduced in most polysaccharides by reaction with sodium periodate. Vicinal diol structures give rise to dialdehydes. For dextran (I) having three adjacent hydroxyl groups in each non-branched anhydro glucopyranoside repeat unit the oxidation is a two step reaction ... 

Detailed studies of the periodate oxidation of dextran and inulin (4-6) have shown evidence for the occurrence of hemiacetal structures formed by reaction of aldehydes with hydroxyl groups of either the same unit (intra-residual) or a neighbouring unit (inter-residual). Inter-residual hemiacetal formation reduces the number of diol struc-... 

A widely applied strategy for the synthesis of various difunctionalized organic molecules, e.g. diols, dialdehydes, etc., relies on the oxidative cleavage of olelinic double bonds. Besides transition metal catalysis for asymmetric synthesis, periodate oxidation and ozonolysis are the standard tools for oxidative bond cleaving reactions. For economic and safety reasons, technically applicable alternatives to osmium-based chemistry and ozonolysis are of great interest. 

Glycol cleavage. The initial periodate oxidation of cellulose, like other chemical reactions, was largely limited to the readily accessible component and has also been used to indicate the accessibility of cellulose substrates [151] (Table 1). Rowland and Cousins [232], based on the influence of periodate oxidation in the crystallinity of cotton, observed about 40% of the component being noncrystalline. Since the m-diol unit is generally more reactive than the /ran.9-diol, the cleavage of the mannose residues would proceed faster than that of the glucose or xylose residues. 

The use of organic and inorganic reagents has proved to be a useful peak identification technique in the chromatographic analysis of physiological fluids for nucleosides and bases (B25, H5, H7-H9, K32). Periodate oxidation has been used for the detection of cis-diol functionalities in ribonucleosides. The use of this reagent is illustrated in Fig. 16. 

Scheme 132). Sodium periodate oxidatively cleaves the diol without decomplexation of the diene moiety. 

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