Phenols, Properties Substituted

Hillard EA, Pigeon P, Vessieres A, Amatore C, Jaouen G (2007) The influence of phenolic hydroxy substitution on the electron transfer and anti-cancer properties of compounds based on the 2-ferrocenyl-1 -phenyl-but- 1-ene motif. Dalton Trans 43 5073-5081... 

The qiplication of natural available lignin is of increased importance because of the lower cost of lignosulfonates in comparison to the cost for synthetic phenol. A substitution for 15 % of phenol with hgnin leads to a cost reduction of aboirt 9.5% [44] and a lignin modified phenolic. Table 2 lists the properties of an extracted lignin polymer [47]. 

Urea, melamine, phenol or substituted phenols can be modified with formaldehyde to produce corresponding resins. An excess of free formaldehyde must be removed in order to prevent interference with the film-forming properties of the paint. These resins can also be used to cross-link alkyd resins. The curing takes place by heating. Phenol-formaldehyde resins are stable to variations of temperature and have a good resistance to moisture, acids and solvents (Piper 1965 Mathias 1984 Fischer and Adams 1990). 

Hydroxybenzene (C HsOH,phenol),and substituted hydroxybenzenes (phenols), much like the arenes to which they are related, enjoy the same enhanced stability (and other properties) of arenes. As a consequence, although both alcohols and phenols possess the hydroxyl (or -OH) functional group, phenols are frequently considered as a separate class of compounds. 

In chlorophenols the aromatic ring of phenol is substituted with one to five chlorine atoms. They have antimicrobial properties and are therefore used as fungicides, herbicides, insecticides, and algicides. Chlorophenols are precursors of agricultural chemicals, pharmaceuticals (e.g.clofibrate), biocides and of anthraquinone dyes. 

One of the characteristic properties of phenol is the ease with which it gives substitution products, this property being particularly well shown by the ready nitration, sulphonation and bromination which the benzene ring in the phenol molecule undergoes. 

The chemical properties of the naphthaleneols are similar to those of phenol and resorcinol, with added reactivity and complexity of substitution... 

Beside being acidic, a significant industrial chemical property of phenol is the extremely high reactivity of its ring toward electrophilic substitution. If steric conditions permit, the substitution leads first to the formation of the 2- or 4-mono derivative, then to the 2,4- or 2,6-diderivative, and finally to the 2,4,6-triderivative. The halogenation of phenol produces mono-, di-, and tribal ophenols. 

Alkaline Catalysts, Resoles. Resole-type phenoHc resins are produced with a molar ratio of formaldehyde to phenol of 1.2 1 to 3.0 1. For substituted phenols, the ratio is usually 1.2 1 to 1.8 1. Common alkaline catalysts are NaOH, Ca(OH)2, and Ba(OH)2. Whereas novolak resins and strong acid catalysis result in a limited number of stmctures and properties, resoles cover a much wider spectmm. Resoles may be soHds or Hquids, water-soluble or -insoluble, alkaline or neutral, slowly curing or highly reactive. In the first step, the phenolate anion is formed by delocali2ation of the negative charge to the ortho and para positions. 

The enhancement of the electrophilic properties of thaHium(III) ttifluoroacetate makes it a very important thaHation reagent. The products of thaHation, eg, arylthaHium bis(ttifluoracetate), undergo a variety of substitution reactions, yielding iodides, fluorides, nitriles, thiophenols, phenols, and biaryls. 

Phenol has different chemical properties from those of typical alcohols. Display the electrostatic potential map for phenol. Does this suggest that phenol is likely to be a stronger or weaker acid than any of the compounds discussed above Compare the electrostatic potential map for 4-nitrophenol to that for phenol. What effect does substitution by nitro have on acid strength Explain your result by considering charge delocalization in the conjugate base. Draw all reasonable Lewis structures for phenoxide anion and for 4-nitrophenoxide anion. Which is more delocalized Is this consistent with experimental pKa s ... 

A biopolymer produced by a particular strain of bacteria is becoming widely used as a substitute for clay in low-solids muds. Since the polymer is attacked readily by bacteria, a bactericide such as paraformaldehyde or a chlorinated phenol also must be used with the biopolymer. The system has more stable properties than the extended bentonite system, because biopolymer exhibits good rheological properties in its own right, and has a better tolerance to salt and calcium. The system can be formulated to include salt, such as potassium chloride. Such a system, however, would then be classed as a nondispersed inhibitive fluid. 

Most relevant for the affinity for A9-THC and analogs to CB-receptors are the phenolic hydroxyl group at C-1, the kind of substitution at C-9, and the properties of the side chain at C-3. Relating to the structure-activity relationships (SAR) between cannabinoids and the CB-receptors, many different modified strucfures of fhis subsfance group were developed and fesfed. The most important variations include variations of the side chain at the olivetolic moiety of the molecules and different substitutions at positions C-11 and C-9. One of the most popular analogous compounds of A9-THC is HU-210 or (-)-trans-ll-OH-A8-THC-DMH, a cannabinoid with a F,l-dimethylheptyl side... 

Derivatives of phenylethanolamine substituted by a phenolic hydroxyl on the para position have been known for some time to exhibit 0-adrenergic agonist activity. As a consequence of this property, the compounds have proven useful as bronchodilators for the treatment of asthma (see Chapter 3). Since such sympathomimetic drugs tend to have undesired activity on the cardiovascular system in addition to the desired activity on the bronchii, considerable work has been devoted to the preparation of compounds that would show selectivity for the adrenergic receptors (02> that predominate in the lung. Attachment of the side chain to a heterocyclic aromatic phenol has been one avenue that has shown promise for achieving this selectivity. 

The supported aqueous phase methodology was applied to the system Pd(OAc)2/5 TPPTS, a catalytic precursor for the Trost-Tsuji reaction. The characterization of the solid by 31P MAS NMR confirms the presence of Pd°(TPPTS)3 as the main surface species. The catalytic properties of the solid were tested for the allylic substitution of E-cinnamylethylcarbonate by different nucleophiles such as ethyl acetoacetate, dimethyl malonate, morpholine, phenol, and 2-mercapto-pyridine. The absence of palladium leaching was demonstrated, and having solved the problem of water leaching from the solid to the organic phase, the SAP-Pd catalyst was successfully recycled several times without loss in its activity. It was used in a continuous flow experiment which... 

Although diselenonium-, ditelluronium- and mixed sulfonium-selenonium dications can exhibit either oxidative or electrophilic properties in reactions with nucleophiles, substitution at the onium chalcogen atom is more typical.96 Owing to the increased stability of heavier dichalcogenium-dications, they react only with highly activated substrates such as aniline and tV,A-dimethylaniline, while no reaction is observed with phenol and diphenylamine.113 Reactions of ditelluronium dications with activated aromatics are also not known (Scheme 44).114... 

We now wish to report the syntheses and physical properties of polysilanes substituted with a phenolic group and carboxylic groups, and polysiloxanes with a phenolic group directly bonded to Si(Figure 2). We also describe basic aqueous development of these materials. 

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