Phenoxy ring

Oxidation reactions occur on several sites of the acid and alcohol moieties, depending on the chemical structures. For example, the trans methyl of the isobutenyl group in chrysanthemates is preferentially oxidized over the cis methyl group in rats, and the 4 -position of the phenoxy ring is oxidized to a larger extent as compared with other positions [8] (Fig. 1). 

An alternative approach to preventing the formation of dihydroartemisinin by simple P450 metabolism is to replace the methyl function in artemether with an aryl function. Phenoxy analogues of DHA can easily be prepared in a one-step synthesis from dihydroartemisinin in a manner similar to the preparation of Ic and Id. In addition to having superior in vivo activity to artesunate and artemether, analogues substituted with a p-fluoro (71a) or trifluoromethyl group (71b), in the phenoxy ring, resist metabolism to DHA . ... 

Various 2-substituted benzofurans 165 are obtained by the interaction of iodo-nium salts 164 with sodium phenoxide in methanol (Scheme 63) [126, 127]. This reaction proceeds via the intramolecular alkylidene carbene insertion into the ortho-CH bond of the phenoxy ring. Furopyridine derivatives 167 can be prepared similarly by the intramolecular aromatic C-H insertion of the alkylidenecarbenes generated by the reaction of alkynyliodonium tosylates 166 with potassium salts of 4- or 3-hydroxypyridines [128]. 

The manufacture of aspirin is based on the synthesis of salicylic acid from phenol. Reaction of carbon dioxide with sodium phenoxide is an electrophilic aromatic substitution on the ortho, para-directing phenoxy ring. The ortho isomer is steam distilled away from the para isomer. 

The results of our analysis (Table 5) show that the general trend of the orders of reactivity of HA s are similar for phenoxyalkanoic compounds classes characterized by a different number of chlorine atoms on the phenoxy-ring or by a different type of alkanoic chain. In general, humic acids of the same origin show a close order of... 

Fig. 3. 2D NOESYspectrum of Triton X-100 in aqueous solution at a concentration of 0.5 CMC with a mixing time of 500 ms, where 1 and 2 are the peaks of the aromatic protons of Triton X-100 ((CH,)3CCH2C(CH))2C6H4OCH2CH2(OC2H4)KOH), 3 and 4 are the peaks of the protons on the first oxyethylene group next to the phenoxy ring, 5 is the overlapped peak of the protons on the polyoxyethylene chain, 6 is the peak of the methylene protons on the hydrophobic chain, 7 is the peak of the dimethyl protons attached to the carbon atom next to the phenoxy ring, and 8 is the peak of the trimethyl protons at the end of the hydrophobic chain. W is the peak of water protons. (Reprinted with permission from ref. 72, Copyright 2000 American Chemical Society.)...

In the case of tetraiodothyroactive structures where the 4 -oxygen is a phenoxide ion (11) and thus only a hydrogen bond acceptor, the donor atoms approach the 4 -phenoxy ring symmetrically from directions both above and below the plane (Figure 8c). However, where the tetraiodo structures are hydroxyls (T A (19)), the outer ring iodines cause the approach of the donor/acceptor atoms to deviate from this pattern. 

Figure 11. Superposition of molecular structure of ThA with (a) ThF (b) T P (c) Th and (d) all of them, illustrating binding volume of thyroactive acid metabolites, assuming 4 -phenoxy ring fixed.

Fluoxetine is a 3-phenoxy-3-phenylpropylamine that exhibits selectivity and high affinity for human SERT and low affinity for NET (Fig. 21.11). It is marketed as a racemic mixture of R- and S-fluoxetine. Its selectivity for SERT inhibition depends on the position of the substituent in the phenoxy ring (Table 21.6). ... 

Removal of a p-nitro group from peroxidative diphenyl ethers drastically reduced their peroxidative activity while increasing the inhibition of carotenoid biosynthesis, provided a substituted formamide substituent is present in the metaposition (1, Fig. 4.1.3). Both the o- and p-derivatives are inactive (reviewed in Ref [27]). Lipophilicity of the phenoxy ring and chain length of the alkyl group up to five carbon atoms increases activity, while branching results in a loss of activity. QSAR equations of the effect of the carbonamide substituent have been calculated [38]. No commercial product has been developed. 

II. The EPR spectrum of tyrosine radicals is known to be affected by the structure of the radical. Spin density in the radical is delocalized over the phenoxy ring with maximum density at the 1, 3, and 5 positions (11,12,13). This spin density distribution leads to a large, anisotropic hyperfine coupling to the 3,5 protons and a small coupling... 

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