5-Aryl-3-aryloxy

Durch Oxidation von N-Acyl-O-aryl-isoharnstoffen mit tert.-Butylhypochlorit erhalt man 5-Aryl-3-aryloxy-1,2,4-oxadiazole z. B. ... 

Aryloxy-tetrazole reagieren in siedendem Benzol mit Benzoyl-chloriden iiber die primaren 1-Acyl-tetrazole unter Stickstoff-Abspaltung zu 5-Aryl-3-aryloxy-l, 2,4-oxadiazoIen227 z.B. ... 

The palladium-catalyzed arylation of 2-phenylphenols and naphthols shows an interesting feature of arylation of C-H bonds, leading to the formation of an (aryl)(aryloxy)palladium(n) intermediate.65,65a,65b The phenolates are suitable as precoordinating groups. The reaction of 2-hydroxybiphenyl with an excess of iodobenzene occurs regioselectively at the two ortho-positions of phenyl group under palladium catalysis (Equation (57)). In the case of 1-naphthol, the peri-position is phenylated (Equation (58)). 

Aryl-, aryloxy- and arylthiocarboxylic acids, N-derivatized amino acids Quinine and quinidine carbamates Methanol—0.1 M 194 ammonium acetate, pH 6.0 (80 20)... 

Thus, in the reaction of aryllead triacetate with phenols, an initial ligand exchange affords an aryl-(aryloxy)lead diacetate intermediate which can have the aryloxy ligand either in the axial position 51 or in the equatorial position 52 (Scheme 9). If the aryloxy group is in the axial position, pseudorotation can easily interconvert this conformer with... 

The reaction is considered to involve two mechanistic patterns i.e.,the reactions of arylpalladium intermediates with (a) phenolates at the ortho-positions, this being similar to the a-arylation of ketones (see Sect. 2.2 and Scheme 4), and with (b) thus formed biphenyl-2-ols as in Eq. (56). While the latter proceeds in both DME and xylene, the use of the less polar solvent is essential for the former to occur effectively. However, the intramolecular cyclization of halophenyl-linked phenols is known to occur in DMA [ 122]. It is worth noting that 0-arylation of phenols to give diaryl ethers occurs when bulky phosphine ligands are used (Eq. 60) [26-28]. This may imply that in the aryl(aryloxy)palladium intermediates, reductive elimination to give the ethers is enhanced by the ligands (Scheme 4). 

A wide variety of substituents are tolerated. The group R can be alkyl, halogen, alkoxy, -amido, azi-domethyl, ester, aryl, aryloxy and aryloyl, and at least one ortho substituent is permissible with no loss in yield. TTie aromatic ring can also be 2-naphthyl, 9,10-dihydro-2-phenanthryl, 3-pyridyl, thiophen-2-yl or pyrrol-3-yl. The group R can be hydrogen, yl, acyl or acetic acid. Beyond Ae antiinflammatory targets, successful reaction substrates include the methyl ketones of a binaphthyl crown ether, a morphinane and a polyaromatic hydrocarbon. The preparation of ibuprofen methyl ester (38) is shown in equation (37) as a typical example. ... 

The reaction of aryllead triacetate with 3,5-di-tert-butylphenol has been shown to yield very hindered di-arylated products (Scheme 13.20) [22a]. The favored pathway must involve the occurrence of covalent aryl(aryloxy)lead(IV) diacetate intermediates, although they have not been detected. 

The activation of carbon dioxide by homogeneous and heterogeneous metal catalysts, as well as the nature of the stoichiometric insertion processes of these catalysts, are examined. The kinetic and mechanistic aspects of CO2 insertion into the M-X bond of M(C0)5X" complexes (M W, Cr and X H, alkyl, aryl, aryloxy, and alkoxy) is investigated. The mechanism of CO2 insertion in these systems is described as an associative interchange (I ) type mechanism where prior loss of coordinated CO is not involved in the insertion process. 

PHENYL OR SUBSTITUTED ARYL COMPOUND - GENERAL 276 PARA ARYL, ARYLOXY OR ARYLAMINO COMPOUND 2211 AROMATIC COMPOUND - POSSIBLY MULTIPLE HALOGEN SUBSTITUTION... 

In the presence of sulfide or sulfhydryl anions, the quinonemethide is attacked and a benzyl thiol formed. The P-aryl ether linkage to the next phenylpropane unit is broken down as a result of neighboring-group attack by the sulfur, eliminating the aryloxy group which becomes reactive phenolate ion (eq. 2). If sulfide is not present, a principal reaction is the formation of the stable aryl enol ether, ArCH=CHOAr. A smaller amount of this product also forms in the presence of sulfhydryl anion. 

The triaLkoxy(aryloxy)boranes are typically monomeric, soluble in most organic solvents, and dissolve in water with hydrolysis to form boric acid and the corresponding alcohol and phenol. Although the rate of hydrolysis is usually very fast, it is dependent on the bulk of the alkyl or aryl substituent groups bonded to the boron atom. Secondary and tertiary alkyl esters are generally more stable than the primary alkyl esters. The boron atom in these compounds is in a trigonal coplanar state with bond hybridization. A vacantp orbital exists along the threefold axis perpendicular to the BO plane. 

Benzothiazole, 2-amino-6-thiocyanato-azo dyes from, 1, 328 Benzothiazole, 2-aryl-synthesis, 6, 321 Benzothiazole, 2-arylamino-synthesis, 6, 323 Benzothiazole, 2-aryloxy-Fries rearrangement, 6, 289 Benzothiazole, 2-benzyl-picrate, 6, 252 Benzothiazole, 2-chloro-dyes from, 1, 321-322 synthesis, 6, 323 Benzothiazole, 2,3-dihydro-oxidation, 6, 272 Benzothiazole, 2-dimethylamino-synthesis, 5, 128... 

Pyridinium salts, l-aryl-4-methoxy-2,6-dimethyl-synthesis, 3, 762 Pyridinium salts, N-aryloxy-rearrangements, 2, 354 Pyridinium salts, 1-benzyl-covalent amination, 2, 239 Pyridinium salts, N-benzyl-reactions... 

Even in Ugi reactions of chiral 4,5-dihydro-3//-pyrrole derivatives with aryloxy substituents vicinal to the cWo-cyclic imino group, a low stereoselectivity was found with either chiral or achiral isocyanides and benzoic acid leading to substituted 2-aminoearbonyl-3-aryl-oxy-1 -benzoylpyrrolid ine derivatives82. 

Aminocarbonyl-phenyI)- 683 O-Aryl 481 (Aryloxy-phenyl)- 684 N-Benzyl- 374f., 614... 

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