1,2,3-Triol grouping

Formic acid is produced from a 1,2,3-triol grouping. As this acid is stable toward periodate, it is readily determined by volumetric or potentiometric titration of the reaction mixture, by highly sensitive spectrophotometric methods, or manometrically. Lead tetraacetate slowly oxidizes formic acid to carbon dioxide, which may complicate the stoichiometry of the glycol-cleavage... 

Oxidative interconversion of cyclitols and derivatives into acyclic, di-carboxylic acids has been widely used for structural elucidation in this series. Early applications of the procedure helped determination of the constitution of shikimic and quinic acids for example, cleavage of the 1,2,3-triol grouping of methyl dihydroshikimate (35) produced a dialdehyde (36), which was oxidized with bromine water to the (known) degradation end product, tricarballylic acid (37). This approach to structural problems has proved particularly successful for determining the configuration of glycosides and related compounds. 

Even higher sugars that eontain an exoeyelie r/c-diol or 1,2,3-triol group are speeifieally attaeked by lead tetraaeetate at the anomeric center and are de-... 

Hirst and Jones (130) describe a general volumetric procedure for the determination of sugars based on the oxidation of the 1,2,3-triol grouping by sodium meta-... 

All heptitols having the favorable, D-erythro, terminal triol group are listed in Table I, together with the yields of the respective heptuloses. Volemitol is unique among the heptitols in having the required configurates) J. K. N, Jones and H. H. Sephton, Can. J. Chem., 38, 753 (1960). 

The rate of production of formic acid by periodate from triol groups has been used in determining the structure of the glycosidically bound trisaccharide solanose. Oxidation and other evidence suggested that the sugar moiety is either trisaccharide (3) or (4). 

Cyclopentanepentols that contain a cis-trans-l,2,3-triol grouping are isomerized by acetic acid-sulfuric acid for example, (l,2,3/4,5)-cyclopentanepentol (239) is rapidly rearranged into the (l,2,3,4/5) isomer (240), and the latter is converted more slowly into the... 

Diester/Ether Diol of Tetrabromophthalic Anhydride. This material [77098-07-8] is prepared from TBPA in a two-step reaction. First TBPA reacts with diethylene glycol to produce an acid ester. The acid ester and propylene oxide then react to give a diester. The final product, a triol having two primary and one secondary hydroxyl group, is used exclusively as a flame retardant for rigid polyurethane foam (53,54). 

Another synthesis of pyrogaHol is hydrolysis of cyclohexane-l,2,3-trione-l,3-dioxime derived from cyclohexanone and sodium nitrite (16). The dehydrogenation of cyclohexane-1,2,3-triol over platinum-group metal catalysts has been reported (17) (see Platinum-GROUP metals). Other catalysts, such as nickel, rhenium, and silver, have also been claimed for this reaction (18). 

Polyurethane foams are formed by reaction with glycerol with poly(propylene oxide), sometimes capped with poly(ethylene oxide) groups with a reaction product of trimethylolpropane and propylene oxide or with other appropriate polyols. A typical reaction sequence is shown below, in which HO—R—OH represents the diol. If a triol is used, a cross-linked product is obtained. 

Perbenzoic acid gave a doubly unsaturated triol monobenzoate. Only two hydroxyl groups could be acetylated, and one was tertiary. The saturated triol reacted with lead tetracetate to give an a glycol. When reacted with chromic acid, it gave a hydroxy lactone. From these observations, Windaus and Gmndmann (11) described the correct stmcture for ergosterol (1). 

A benzylidene acetal is a commonly used protective group for 1,2- and 1,3-diols. In the case of a 1,2,3-triol the 1,3-acetal is the preferred product. It has the advantage that it can be removed under neutral conditions by hydrogenolysis or by acid hydrolysis. Benzyl groups and isolated olefins have been hydrogenated in the presence of 1,3-benzylidene acetals. Benzylidene acetals of 1,2-diols are more susceptible to hydrogenolysis than are those of 1,3-diols. In fact, the former can be removed in the presence of the latter. A polymer-bound benzylidene acetal has also been prepared." ... 

Hydroxy derivatives of silanes in which the hydroxyl groups are attached to a silicon atom are named by adding the suffices -ol, -diol, -triol etc., to the name of the parent compound. Examples are ... 

The 11-keto group is relatively difficult to attack, due to steric hindrance. However, reaction of 3j -hydroxy-5a-androstane-l 1,17-dione (37) with methylmagnesium bromide at 25° unexpectedly gives a 30% yield of 1 la,17a-dimethyl-5a-androstane-3j5,lljS,17i -triol (38) in addition to the 17-monomethyl product (39). 

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