3- Hydroxyphenol

Hydrogen bonding to a carbonyl group causes a shift to lower frequency of 40 to 60 cm k Acids, amides, enolized /3-keto carbonyl systems, and o-hydroxyphenol and o-aminophenyl carbonyl compounds show this effect. All carbonyl compounds tend to give slightly lower values for the carbonyl stretching frequency in the solid state compared with the value for dilute solutions. 

The most important commercial chemical reactions of phenol are condensation reactions. The condensation reaction between phenol and formaldehyde yields phenoHc resins whereas the condensation of phenol and acetone yields bisphenol A (2,2-bis-(4-hydroxyphenol)propane). PhenoHc resins and bisphenol A [80-05-7] account for more than two-thirds of U.S. phenol consumption (1). 

Figure 5.46 Product-ion spectra of (a) Bosentan (1) [M -F H] 552.1917, and its (b) hydroxy metabolite (2) [M + H]+ 568.1866, (c) phenol metabolite (3) [M + H] 538.1760, and (d) hydroxyphenol metabolite (4) [M-FH] 554.1790. Reprinted by permission of Elsevier Science from Exact mass measurement of product ions for the structural elucidation of drug metabolites with a tandem quadrupole orthogonal-acceleration time-of-flight mass spectrometer , by Hopfgartner, G., Chemushevich, I. V., Covey, T., Plomley, J. B. andBonner, K., Journal of the American Society for Mass Spectrometry, Vo. 10, pp. 1305-1314, Copyright 1999 by the American Society for Mass Spectrometry.

The reaction products from 2,4-dichlorophenol were tetrachloro-phenoxyphenols and tetrachlorodihydroxybiphenyls (Figure 5), as determined from their mass spectra and those of their methyl ethers. 4,6-Dichloro-2-(2, 4 -dichlorophenoxy)phenol (V) was the major phenoxy-phenol the mass spectral fragmentation pattern of o-hydroxyphenol ethers is quite characteristic since a hydrogen transfer occurs during the fragmentation (Figure 6). A trace of a trichlorophenoxyphenol also was detected and was formed presumably by the unsensitized reductive loss of chlorine, discussed previously. 

The effects of glyphosate on phenolic compound production are two-fold 1) accumulation of phenolic compounds that are derivatives of aromatic amino acids is reduced and 2) pools of phenolic compounds derived from constituents of the shikimate pathway prior to 5-enolpyruvylshikimate-3-phosphate become larger. Assays that do not distinguish between effects on these two groups, such as that for hydroxyphenolics of Singleton and Rossi (18), can lead to equivocal and difficult to interpret results (e.g. 3-5). 

A one-pot process to form 1,3,4-substituted pyrazoles 25 by Suzuki coupling of arylboronic acids to chromone 24, followed by condensation with hydrazine has been reported <06JCO286>. The synthesis of 3 or 5-o-hydroxyphenol-4-benzylpyrazoles has been accomplished by treatment of 3-benzylchromones, 3-benzylflavones and their 4-thiochromone analogs with hydrazine hydrate in hot pyridine <06EJO2825>. 

Despite the undeniable synthetic value of the benzannulation reaction of aryl and alkenyl Fischer carbene complexes, the details of its mechanism at the molecular level remain to be ascertained. Indeed, although a relatively large number of theoretical studies have been directed to the study of the molecular and electronic structure of Fischer carbene complexes [22], few studies have been devoted to the analysis of the reaction mechanisms of processes involving this kind of complexes [23-30]. The aim of this work is to present a summary of our theoretical research on the reaction mechanism of the Dotz reaction between ethyne and vinyl-substituted hydroxycarbene species to yield p-hydroxyphenol. 

C. F. Correia, R. C. Guedes, R. M. Borges dos Santos, B. J. Costa Cabral, J. A. Martinho Simoes. O-H Bond Dissociation Enthalpies in Hydroxyphenols. A Time-Resolved Photoacoustic Calorimetry and Quantum Chemistry Study. Phys. Chem. Chem. Phys. 2004, 6, 2109-2118. 

NUMEROUS MONO-, DI-, ANDTRI-, HYDROXYPHENOLS, BENZOIC ACIDS AND AROMATIC COMPOUNDS... 

Synonyms AI3-00072 Arctuvin p-Benzenediol 1,4-Benzenediol Benzohydroquinone Benzoquinol Black and white bleaching cream BRN 0605970 CCRIS 714 Dihydroxybenzene jO-Dlhydroxybenzene 1,4-Dihydroxybenzene p-Dioxobenzene EINECS 204-617-8 Eldopaque Eldoquin HQ Hydroquinol Hydroquinole a-Hydroquinone p-Hydroquinone 4-Hydroxy-phenol p-Hydroxyphenol NC1-C55834 NSC 9247 Quinol p-Quinol Quinone Tecquinol Tenox HQ Tequinol UN 2662 USAF EK-356. 

Hydroxyphenol, see Hydroquinone p-Hydroxyphenol, see Hydroquinone 4-Hydroxy-3-(l-phenyl-3-oxobutyl)coumarin, see Warfarin 1 -Hydroxypropane, see 1 -Propanol 3 Hydroxypropene, see Allyl alcohol 3 Hydroxypropionic acid lactone, see p-Propiolactone... 

Structural information on aromatic donor molecule binding was obtained initially by using H NMR relaxation measurements to give distances from the heme iron atom to protons of the bound molecule. For example, indole-3-propionic acid, a structural homologue of the plant hormone indole-3-acetic acid, was found to bind approximately 9-10 A from the heme iron atom and at a particular angle to the heme plane (234). The disadvantage of this method is that the orientation with respect to the polypeptide chain cannot be defined. Other donor molecules examined include 4-methylphenol (p-cresol) (235), 3-hydroxyphenol (resorcinol), 2-methoxy-4-methylphenol and benzhydroxamic acid (236), methyl 2-pyridyl sulfide and methylp-tolyl sulfide (237), and L-tyrosine and D-tyrosine (238). Distance constraints of between 8.4 and 12.0 A have been reported (235-238). Aromatic donor proton to heme iron distances of 6 A reported earlier for aminotriazole and 3-hydroxyphenol (resorcinol) are too short because of an inappropriate estimate of the molecular correlation time (239), a parameter required for the calculations. Distance information for a series of aromatic phenols and amines bound to Mn(III)-substituted HRP C has been published (240). 

Due to its equally high affinity for all a-and p-receptors, epinephrine does not permit selective activation of a particular receptor subtype. Like most catecholamines, it is also unsuitable for oral administration (catechol is a trivial name for o-hydroxyphenol). Norepinephrine differs from epinephrine by its high affinity for a-receptors and low affinity for P2-receptors. In contrast, isoproterenol has high affinity for p-recep-tors, but virtually none for a-receptors (A). 

Bisphenol A [(bis-4-hydroxyphenol)dimethylmethane], used for the production of epoxy resins and polycarbonates, is obtained by the acidic condensation of phenol and acetone. Here, the carbonium ion produced by the protonation of acetone attacks the phenol molecule at the para position producing a quinoidal oxonium ion that loses water and rearranges to a p-isopropylphenol carbonium ion. The water attacks another phenol molecule, also in the para position, giving another quinoidal structure that rearranges to bisphenol A. It has been found that bisphenol A may be involved in one of the endocrine systems. The consequences of this are still being determined. 

White, W. F., Zhao, D. (3R,4S)-3-[4-(4-Fluorophenyl)-4-hydroxypiperidin-1-yl]chroman-4,7-diol a conformationally restricted analoque of the NR2B subtype-selective NMD A antagonist (1S,2S)-1-(4-hydroxyphenol)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol, J. Med. Chem. 1998, 41, 1172-1184. 

Herbicides are the biocides most likely to affect the metabolism of plants, including secondary metabolism [107]. The synthesis of hydroxyphenolics and anthocyanin in plants can be influenced by a variety of environmental and chemical stimuli. Some herbicides were found to raise the levels of these compounds in plants [108] whilst others had the opposite effect [109]. The products of secondary metabolism are controlled by enzymes, including PAL and chalcone isomerase (Cl), and several herbicides appear to intensify the activities of those enzymes involved in the accumulation of hydroxyphenolic compounds and anthocyanin biosynthesis in several plant species [109-111] whereas others depress this activity [112]. For example,... 

Lindsay BS, Battershill CN, Copp BR (1998) Isolation of 2-(3 -Bromo-4 -hydroxyphenol) ethanamine from the New Zealand Ascidian Cnemidocarpa bicornuta. J Nat Prod 61 857... 

Hammett s equation was also established for substituted phenols from the elementary hydroxyl radical rate constants. The Hammett resonance constant was used to derive a QSAR model for substituted phenols. The simple Hammett equation has been shown to fail in the presence of electron-withdrawing or electron-donating substituents, such as an -OH group (Hansch and Leo, 1995). For this reason, the derived resonance constants such as o°, cr, and o+ were tested in different cases. In the case of multiple substituents, the resonance constants were summed. Figure 5.24 demonstrates a Hammett correlation for substituted phenols. The least-substituted compound, phenol, was used as a reference compound. Figure 5.24 shows the effects of different substituents on the degradation rates of phenols. Nitrophenol reacted the fastest, while methoxyphenol and hydroxyphenol reacted at a slower rate. This Hammett correlation can be used to predict degradation rate constants for compounds similar in structure. 

The reaction pathway of 2,4-dichlorophenol is illustrated in Figure 9.16. The CT reaction site leads to the product 2-chloro-4-hydroxyphenol (D Oliv-iera et al., 1993). Bond cleavage of the aromatic ring is observed to yield the minor products l-hydroxy-4-chlorophenol and 2-chloro-2,5-cyclodihexene-1,4-one, as shown in Figure 9.17. 

Similarly, hydroxyphenols have common names, which are listed first under each of the following illustrations, while the IUPAC names are listed last. 

Synonyms 2-hydroxyphenol, o-diphenol, 1,2-benzenediol, o-diydroxyben-zene Formula C6H502 Structure ... 

Synonyms nt-hydroxyphenol 3-hydroxyphenol 1,3-benzenediol 1,3-dihy-droxybenzene, Formula C6H602 Structure ... 

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