Acids polyhydroxy aromatic

Phenols can be mononitrated in a two-phase system (ether/water) by sodium nitrate and aqueous hydrochloric acid in the presence of a catalytic amount of lanthanum(III) nitrate in yields genei ly above 80%. Phenol itself gives 2 1 ortho.para nitration, while phenols substituted in the para position give predominantly ortho nitration with some meta nitration (equation 21). As shown recently nitration of phenols in the two-phase system occurs even without lanthanum(III) nitrate. By use of sodium nitrate, aqueous sulfuric acid and a catalytic amount of sodium nitrite in the two-phase system mononitration of phenols can be achieved in high yields. Under these conditions starting from 3-substituted phenols in addition to the nitro compounds formation of quinones has been observed. Polyhydroxy aromatics are typically difficult to nitrate directly. Thus, 4,6-dinitroresorcinol (45) has been synthesized from resorcinol diacetate (44) with nitric acid or mixed solutions of nitric acid/sulfuric acid containing urea as a nitrous trap (equation 22). ... 

Tannins are widespread in nature but are quantitatively and geochemically less important than lignin. They are important in making plants less palatable to herbivores and, when extracted by steeping plant material, particularly bark and leaves, in water, they can be used for tanning leather. The structural units of tannins are polyhydroxy aromatic acids, such as gallic acid and... 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

The reaction is most important for the preparation of carbinols from certain aromatic and heterocyclic aldehydes and for the preparation of several aliphatic polyhydroxy compounds. In the normal Cannizzaro reaction the theoretical yield of alcohol is only 50% because half of the aldehyde is converted to the acid. A mixture of an aldehyde with excess formaldehyde, however, results in a dismutation in which most of the higher aldehyde is reduced formaldehyde is oxidized to sodium formate, viz., ... 

These compds may be modified by monocar-boxylic acids or polyhydroxy alcohols. This definition includes the polycarbonates (qv), which are a well-defined segment of the general class of polyesters. Unsaturated polyesters, which are produced when any of the reactants contain non-aromatic unsaturation, can be, cross-linked or copolymerized with an unsaturated copolymerizable monomer. The. formulas and properties of the class polyester are as varied and extensive as the reactants themselves. For specific information on the various sub-classes and sub-sub classes, the following refs should be consulted 9,10, 11, 16a, 17,18,... 

Comparable yields are also obtained in the acylation of activated aromatic compounds with carboxylic acids using a substoichiometric amount of bis[(frifluoromefhyl)sulfonyl]amine in [emim][NTf2]. Thus, polyhydroxy-deoxybenzoins 30 can be synfhesized in 55%-74% yield by acylation of polyhydroxylafed aromafic compounds 28 with suitable phenylacetic acids 29 (Scheme 3.6). 

Polycyclic aromatic hydrocarbons, 61 Polyesters in waxes, 143,146 Polyethyleneglycol esters, 317 Polyglycerol esters, 228, 232 Polyhydroxy acids, 20,175 Polymerization, 174 Polymorphism, 213,321,325,343,346,... 

The hydroxyl groups of the PEGs react with aliphatic or aromatic isocyanates to form urethanes (carbamic acid esters). Divalent isocyanates (diisocyanates) and polyhydroxy compounds form high molecular weight polyurethanes by polyaddition ... 

The detection of aromatic mono and polyhydroxy compounds can be carried out on the basis of color reactions of the product of coupling with diazotized sulfanilic acid (influence of pH) (8). 

Their chemical structure is rather complex. The main characteristic feature is that glucose (- dextrose) is partly or completely esterified with aromatic polyhydroxy carboxylic acids, e. g., gallic acid (3,4,5 trihydroxy benzoic acid) or its esters, e.g., di-galloyl-gallic acid and its condensation products. There are two classes hydrolyzable and condensed t. 

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