Phenolic compounds condensed

Leucaena leucocephala (Lam.) De Wit Yin He Huan (leaf, seed) Leucanol, leucaenine, phenolic compounds, condensed tannins.60-228 This herb is toxic. Anthelmintic, for diabetes, an emollient, emmenagogue. 

Polyphenols Sinapicacid Free and esterified phenolic compounds condensed tannins Dark colour Bitter taste Astringent effects React with fimctional groups at protein, similar to isothiocyanates Use of reducing agents to avoid oxidation Pre-extraction with alcohols Membrane processing Adsorption processing... 

Bisphenol A is a solid material in the form of white flakes, insoluble in water but soluble in alcohols. As a phenolic compound, it reacts with strong alkaline solutions. Bisphenol A is an important monomer for producing epoxy resins, polycarbonates, and polysulfones. It is produced by the condensation reaction of acetone and phenol in the presence of HCI. (See Chapter 10, p. 273)... 

Organophosphate Ester Hydraulic Fluids. Organophosphate esters are made by condensing an alcohol (aryl or alkyl) with phosphorus oxychloride in the presence of a metal catalyst (Muir 1984) to produce trialkyl, tri(alkyl/aryl), or triaryl phosphates. For the aryl phosphates, phenol or mixtures of alkylated phenols (e.g., isobutylated phenol, a mixture of several /-butylphenols) are used as the starting alcohols to produce potentially very complex mixtures of organophosphate esters. Some phosphate esters (e.g., tricresyl and trixylyl phosphates) are made from phenolic mixtures such as cresylic acid, which is a complex mixture of many phenolic compounds. The composition of these phenols varies with the source of the cresylic acid, as does the resultant phosphate ester. The phosphate esters manufactured from alkylated phenylated phenols are expected to have less batch-to-batch variations than the cresylic acid derived phosphate esters. The differences in physical properties between different manufacturers of the same phosphate ester are expected to be larger than batch-to-batch variations within one manufacturer. 

When heated with a strong acid, pentoses and hexoses are dehydrated to form furfural and hydroxymethylfurfural derivatives respectively (Figure 9.20), the aldehyde groups of which will then condense with a phenolic compound to form a coloured product. This reaction forms the basis of some of the oldest qualitative tests for the detection of carbohydrates, e.g. the Molisch test using concentrated sulphuric acid and a-naphthol. 

Pool PL, Lin PZ. 1982. Mutagenicity testing in the Salmonella typhimurium assay of phenolic compounds and phenolic fractions obtained from smokehouse smoke condensates. Food Chem Toxicol 29 383-391. 

Phenolic compounds can be condensed forming aryl-aryl and aryl-oxygen-aryl (ether linkages) bonds to yield diaryl and diaryl ether polymers (59). These are in many ways similar to natural humic acids, confirming earlier research by others (60-62) that humic acids are formed from the copolymerization of phenolic compounds with amino acids, peptides, and amino sugars. 

Retorting of oil shales to produce shale oil results in wastes (condensate water and solid semi-coke residue) that are heavily contaminated with organic compounds, especially phenolic compounds. Semi-coke leachate is typically alkaline (Kundel Liblik 2000) and can contain several hundred mg/L phenol in Estonia, in addition to potentially toxic heavy metals and trace elements, for example, As, B, F, Mo, and Se, which might be mobilized during leaching by water. Volatilization of phenols from leachate lagoons can also impact atmospheric quality. 

Coal tar is the condensation product obtained by cooling to approximately ambient temperature, the gas evolved in the destructive distillation of coal. It is a black viscous liquid denser than water and composed primarily of a complex mixture of condensed ring aromatic hydrocarbons. It may contain phenolic compounds, aromatic nitrogen bases and their alkyl derivatives, and paraffinic and olefinic hydrocarbons. Coal-tar pitch is the residue from the distillation of coal tar. It is a black solid having a softening point of 30—180°C (86—359°F). 

OC-Santalol. Sandalwood oil is comprised of mainly (90%) a- and p-santalol, which gives the oil the woody, tenacious sandalwood odor. An impure a-santalol [115-71-9] (100) can be isolated by the distillation of the oil. p-Santalol [77-42-9] (101) is also isolated but in much smaller amounts. The price of sandalwood oil, E. Indian, in 1995 was 286/kg, and the oil from Indonesia was 187/kg (69). The high price of these oils has created the need to synthesize new materials with the sandalwood odor. The terpenophenols are manufactured by condensation of camphene with phenolic compounds followed by hydrogenation to the cycloaliphatic alcohols (194). 

Glycosides, particularly of phenolic compounds, are widely distributed in plant tissues (2,10). Glycosides of anthocyanidins, flavones, flavanols, flavanones, flavanonols, stilbenes and saponins, gallic acid derivatives, and condensed tannins are all common. 

In 1915 Hoesch showed that the condensation of a nitrile with a phenolic compound led to the formation of a ketimine hydrochloride which could be easily hydrolysed to give a ketone. 

Another major problem associated with the extraction of DNA from archaeological specimens is that the procedure often co-extracts impurities that can later complicate, or prevent, the study of the extracted DNA by inhibiting PCR amplification (reviewed by 5). Commonly encountered inhibitory substances found in aDNA extracted from teeth, bones, mummified tissue, and coprolites include humic acids, ftilvic acids, tannins, porphyrin products, phenolic compounds, hematin, and collagen type I (37—42). The formation of Maillard products, commonly encountered in coprolite samples, can also prevent PCR amplification by causing DNA to become inaccessibly trapped in these sugar-derived condensation products (12). As the negative results in many aDNA studies are attributed to the presence of PCR inhibitors, our extraction method outlined below pays particular attention to the problem and offers a simple test for the presence of PCR inhibitors in DNA extracts. 

The condensation of allylic alcohols with phenolic compounds in the presence of an acid catalyst yields allylphenols. This reaction was used 86 in a synthesis of vitamin K (LXXVa) by condensing phytol with 2-methyl-l,4-naphthohydroquinone in dioxane with oxalic or trichloroacetic acid as catalyst the hydroquinone first formed was oxidized to... 

Dienes also condense with phenolic compounds, but the product is usually a chroman. Isoprene 91 condenses with phenol to yield 2,2-dimethylchroman LXXVI, and phytadiene 92 Condenses with trimethyl-... 

---