Phenol functions

Weak cation exchanger—macroreticular type—carboxylic acid or phenolic functionality... 

Sandmeyer Reaction. This general reaction allows the phenol function to be introduced. The technique complements chlorination insofar as it makes it possible to produce chlorophenols chloriaated in the meta position from the corresponding meta-chlotinated anilines. 

Aryl tetrazolyl ethers (519) are reduced by palladium on charcoal to give the arene and the tetrazolinone (520) (77AHC(2D323) this reaction is used for the removal of phenolic functionality. 

From the intramolecular coupling product, just the two MEM-groups protecting the phenol functions (MEM = 2-methoxyethoxymethyl) have to be removed, in order to obtain the target molecule. 

It yields a phenylurethane melting at 41°, a semi-carbazone melting at 219° to 220°, and an oxime melting at 125°. The OH group appears to possess alcoholic as well as phenolic functions, forming acetic and benzoic esters, as well as direct combinations with alkalis. 

In the polyazamacrocyclic phenols [64], an acidic function, the phenol group, has an intra-annular orientation while the basic units, the nitrogen atoms of the macrocycles, have no defined orientation. In water at 25°C, the pATa values of the phenols were measured and compared with those of other macrocyclic and non-macrocyclic phenols (Kimura et al., 1987a,b). Because the nitrogen atoms and the phenol function both possess acid-base properties, more than one pXg value could be measured. By the use of UV measurements, the values of the phenol group could be distinguished from those of the amines. 

The Kumada-Corriu reaction is characterized by mild conditions and clean conversions [2]. A disadvantage of previous Kumada-Corriu reactions was due to the use of homogeneous catalysts, with more difficult product separation. Recently, an unsymmetrical salen-type nickel(II) complex was synthesized with a phenol functionality that allows this compound to be linked to Merrifield resin polymer beads (see original citation in [2]). By this means, heterogeneously catalyzed Kumada-Corriu reactions have become possible. 

Fig. 12. Cooperative closed dimers assembled from phenol-functionalized porphyrins.

A second strategy is to attach a linker (also referred to as a handle or anchor) to the resin followed by assembly of the molecule. A linker is bifunctional spacer that serves to link the initial synthetic unit to the support in two discrete steps (Fig. 3). To attach a linker to a chloromethyl-PS resin, a phenol functionality such as handle 4 is used to form an ether bond (Fig. 4). To attach the same handle to an amino-functionalized support, acetoxy function 5 or a longer methylene spacer of the corresponding phenol is applied to form an amide bond. Both of these resins perform similarly and only differ in their initial starting resin [4], An alternative approach is to prepare a preformed handle in which the first building block is prederivatized to the linker and this moiety is attached to the resin. For peptide synthesis, this practice is common for the preparation of C-terminal peptide acids in order to reduce the amount of racemization of the a-carbon at the anchoring position [5],... 

Condensation of 2,4-dihydroxypropiophenone (172) with benzoyl chloride and sodium benzoate goes to afford chromone 174, probably via ester 173. This procedure is known as the Kostanecki-Robinson reaction Methylation (175) of the remaining phenolic function by means of dimethyl sulfate, followed by reaction... 

In preliminary studies various metal salts such as PdCl2 were attached to the ligands and the complexes characterized by NMR spectroscopy and X-ray crystallography. Typical examples are the palladium complexes (32)—(44) (Scheme 9).66 The catalytic profiles of these and other transition metal complexes prepared by this method still need to be defined. Moreover, solid-phase synthetic versions would be advantageous, and this may well be possible via the (protected) phenol function. 

The elaboration of 113 to (—)-kinamycins C, F, and J, is shown in Scheme 3.19. To access ( )-kinamycin C (3), the silyl ether function of 113 was cleaved with aqueous hydrochloric acid (95 %). Alternatively, treatment of 113 with lithium hydroxide served to liberate the phenol function and saponify the three acetate esters, to provide ( )-kinamycin F (6) in 92 % yield. Finally, acylation of the tertiary hydroxyl of 113 (acetic anhydride, triethylamine) afforded a tetraacetate. Cleavage of the silyl ether then provided ( )-kinamycin J (10) in 80 % over two steps. 

Titanates can, in contact with ingredients containing phenolic functionality, produce colouration. Zirconates generally do not produce colour when in contact with phenols. 

V) with a reactive methylene group at C6. According to modern concepts, the phenolic hydroxyl group is believed to activate the positions ortho and para to it. In the case of kojic acid, of the three positions in question, only the one ortho position, namely at C6, is available for substitution. This activating effect of the phenolic function would be particularly marked in alkaline media, where kojic acid probably exists in the form of a phenoxide ion (LXIII) the negative charge would be shared by C6 (LXIV), where it... 

CTABr and hydroxy and phenol functionalized micelles. Rate comparisons... 

There is a brief reference to electroreductive silicon polymer formation in COMC II (1995) (chapter Organopolysilanes, p 96), but the very limited extent of the field at that time precluded further comment. Since then, the field has seen considerable progress, and the mild conditions have permitted the synthesis of functionalized polymers of moderate molecular weight (104), an example of which is the co-polymer poly(rncthyM-rncthoxymethoxyphcnylsilylene)-r -poly(methylphenylsilylene), 26, with a protected phenolic function, which was prepared with a molecular weight Mw= 19,000.96 Deprotection afforded the phenolic polymer. Several reviews on the area have been published.113-115... 

This formally [3+2+1] cycloaddition reaction proceeds with remarkable regioselectivity when unsymmetrical alkynes 1 are used. In this case, it is observed that the larger substituent (e.g. Ri in Figure 1) is incorporated ortho to the phenol function [4], with only few exceptions [5,6]. 

This group of pesticides comprises different families of chemicals with her-bicidal action including substituted phenols, chlorinated aliphatic acids, chloro-phenoxy alkanoic acids, and substituted benzoic acids, which possess carboxyl or phenolic functional groups capable of ionization in aqueous media to yield anionic species [47,151,168-170]. 

The phenolic functional group consists of a hydroxyl attached directly to a carbon atom of an aromatic ring. The OH group can also be the consequence of further oxidation or combination with other pollutants such as pesticides, aldehydes, and alcohols (i. e., 2,4-D, cyclic alcohols, cresols, naphthols, quinones, nitrophenols, and pentachlorophenol compounds) forming new more toxic compounds [17,42,160]. 

The flexibility and the different conformations adopted by the re-sorc[4]arene can be rigidified in the cone shape configuration by bridging the phenol functions with different substituents [38]. We will report here on the tetra-bridged phosphorus cavitands (phosphocavitand), whose general structure is presented in Scheme 2 [39]. 

The haloacetate group, also used as a protecting group for the phenolic function, can be removed by treatment with sodium telluride in DME, giving the parent phenol. ... 

Fig. 7.24 Substitution of a pyrrolo for a phenolic function to act at as a H-bond donor for receptor interactions but is resistant to glu-curonidation.

F]Fluoroiodomethane, a valuable synthetic precursor for the introduction of a fluoromethyl group into radiopharmaceuticals, has been prepared from diiodomethane (Scheme 55) [224]. Its reactivity toward amine, acid, thiol or phenolate functions has also been studied. 

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