Multiple Hydroxyl Compounds

Streptomyces nodosus produces natural products such as amphotericin A and B. These are macrocyclic (large-ring) compounds containing numerous (three to seven) double bonds and multiple hydroxyl groups which are usually located on one side of the molecule. Amphotericin B (9.103) and the very similar nystatin (9.104) are antifungal... 

Gallotannins are hydrolysable tannins with a polyol core (referring to a compound with multiple hydroxyl groups) substituted with 10-12 gallic acid residues. Gallotannins contain the characteristic raeto-depside bonds (1.91) between gallic acid residues. This bond is more labile than an aliphatic ester bond, and can be methanolyzed with a weak acid in methanol. In contrast, methanolysis of an aliphatic ester bond requires methanol with a strong mineral acid and heat. 

Vapor-phase nitration of paraffin hydrocarbons, particularly propane, can be brought about by uncatalyzed contact between a large excess of hydrocarbon and nitric acid vapor at around 400°C, followed by quenching. A multiplicity of nitrated and oxidized products results from nitrating propane nitromethane, nitroethane, nitropropanes, and carbon dioxide all appear, but yields of useful products are fair. Materials of construction must be very oxidation-resistant and are usually of ceramic-lined steel. The nitroparaffins have found limited use as fuels for race cars, submarines, and model airplanes. Their reduction products, the amines, and other hydroxyl compounds resulting from aldol condensations have made a great many new aliphatic syntheses possible because of their ready reactivity. 

The main function of carbohydrates in living organisms is as a source of energy, both immediate and stored. Foods rich in carbohydrates include pasta, milk, fruit, bread, and potatoes. Carbohydrates are compounds that contain multiple hydroxyl groups (—OH) as well as a carbonyl functional group (C=0). These molecules range in size from single monomers to polymers made of hundreds or even thousands of monomer units. 

I Carbohydrates are compounds that contain multiple hydroxyl groups (-0H) and a carbonyl functional group (C=0). 

As implied by Equation 14b, a polymer with multiple hydroxyl groups will react with pentavalent or trivalent phosphorous electrophiles to crosslink the polymer if a molar excess of the phosphorus compound is present. This was verified by Doughty, who found that phosphorous halide or sulfide/lignin reactions with a greater than 1/1 mole ratio produced insoluble products (183). If the number of moles of phosphorous compound are equal or less than the moles oflignin in the reaction, the soluble reaction product can be further reacted with mono and polyhydroxy compounds to produce flame retardant resins with film- forming capacity (185). 

Many drug compounds and metabolites that have multiple hydroxyl, carboxyl, and... 

The presence of more than one polar group in a compound will inaease that compound s solubility in water and decrease its solubility in nonpolar solvents. For example, sugars, such as cellobiose, contain multiple hydroxyl and/or acetal groups and are water soluble and ether insoluble. Cholesterol, which has only a single hydroxyl group on its 27 carbon atoms, is insoluble in water and quite soluble in ether. 

About 8,000 phytochemical compounds have been reported as flavonoids, which are formed by the combination of multiple hydroxyl, methoxy, and 0-glycoside groups on the basic benzo-y-pyrone skeleton... 

Using the parent compound depletion method, pyrethroid metabolic rate constants (i.e., Umax and K, hast, etc.) for hydroxylation by cytochrome P450 enzymes or hydrolysis by carboxylesterases were developed by Scollon et al. (2009). The sources of the enzymes were rat and human microsomes. The pyrethroids they studied included bifenthrin, S-bioallethrin, bioresmethrin, p-cyfluthrin, cypermethrin, cis-permethrin, and frans-permethrin. The depletion method considers multiple hydroxylations as a single biotransformation at sites on either the acid or alcohol moieties, or on a combination of both. The metabolic pathways (Tables D1-D15 and E1-E15 of Appendices D and E, respectively) require Umax, Am, and values for the individual hydroxylated and hydrolyzed products. It is interesting that only bioresmethrin and cypermethrin per se were found to actually be hydrolyzed. 

Macrocyclic compounds with multiple hydroxyl groups on one rim, as they are common for many cyclodextrins and calixarenes, have a tendency to form barrel-sh ed dimers that, due to their overall dimensions, often lie sideways onto the electrode surface. In the case of a-, P-, and y-cyclodextrin, which are macrocyclic oligosaccharides that have 10,12, or 14 hydroxyl groups on the upper rim and 5, 6, or 7 hydroxyl groups on the lower rim, not only dimers but whole tubes can be formed on Au(lll) (Figure 20.28).The specific range of potentials within which these... 

Potentiometric titration of these compounds has been demonstrated after formation of the sulfate esters (101). They are titrated with a cationic surfactant, as described in Chapter 16. Since there are multiple hydroxyl groups available for the derivatization reaction, response factors must be developed for each commercial product. 

---