Borates, catechol

B-C bonds, 3, 97 B-N bonds, 3, 97 B-O bonds, 3,94 B-P bonds, 3, 97 B-Si bonds, 3, 97 oxo acid anion complexes, 3, 96 Borates, alkoxo-, 3, 94 Borates, amidotrihydro-, 3,92 Borates, aryloxo-, 3, 94 Borates, carboxylato-, 3,96 Borates, catechol, 3,95 Borates, chlorosulfato-, 3,97 Borates, dicarboxylato-, 3,96 Borates, dipyrazol-l-yl-, 3, 92 Borates, halogeno-, 3,92 Borates, halogenohydro-, 3,90 Borates, hydro-, 3,90 Borates, hydrohydroxo-, 3,90 Borates, hydropyrazol-l-yl-, 3, 92 Borates, hydroxo-, 3,94 Borates, hydroxycarboxylato-, 3,96 Borates, inositol, 3, 95 Borates, monoalkyl-, 3, 92 Borates, monophosphido-, 3, 92 Borates, peroxohydroxo-, 3, 94 Borates, polyol, 3, 95 Borates, pyrrol-l-yl-, 3, 92 Borates, sulfato-, 3, 97 Borates, tetrabromo-, 3, 92 Borates, tetrachloro-, 3, 92 Borates, tetrafluoro-, 3, 92 minerals, 6, 847 Borates, tetrahalogeno-mixed, 3, 93 nB NMR, 3, 92 Borates, tetraiodo-, 3, 92 Borates, tetranitrato-, 3, 96 Borates, tetraperchlorato-, 3, 97 Borates, tripyrazol-l-yl-, 3, 92 Borax, 3,101 Borazines... 

Catechols can be protected as diethers or diesters by methods that have been described to protect phenols. However, formation of cyclic acetals and ketals (e.g., methylenedioxy, acetonide, cyclohexylidenedioxy, diphenylmethylenedioxy derivatives) or cyclic esters (e.g., borates or carbonates) selectively protects the two adjacent hydroxyl groups in the presence of isolated phenol groups. 

A cyclic borate can be used to protect a catechol group during base-catalyzed alkylation or acylation of an isolated phenol group the borate ester is then readily hydrolyzed by dilute acid. ... 

Catecholamines and catechol Catecholamines catechol and serotonin Cu(II)-catalyzed luminol- H202 Phosphate buffer (pH 9.2) KMn04 in H2S04 Borate buffer (pH 9.5)... 

The more stable boron chelates can be isolated even from aqueous solution, whereas those of lower stabilities are only accessible from non-aqueous media. Catechol- and inositol-borates (3, 5 and 6) possesses a well-defined monomeric structure,75 whereas those obtained from monosaccharides and alditols are polymeric.121 A crystal structure determination122 has been carried out for sodium scyUo-inositol diborate (6). 

Aryl borates such as catechol butylborate and triphenyl borate undergo a syn -stereoselective reaction with arylazirines.41 The syn-stereoselectivity was attributed to a transition state where the phenoxide tethered to the boron is transferred intramolec-ularly to the most substituted carbon. The reaction is completed when the phenoxide anion tethered to the boron reacts with the most substituted carbon of the substrate in an intramolecular reaction. 

Finally, two potential models for the Mo and Fe sites of sulfite oxidase have been prepared in which a hydrotris(3,5-dimethylpyrazolyl)borate complex of oxomolybdenum(V) is covalently attached to one of the phenyl rings of a tetraphenylporphinatoiron(III) derivative in which three phenyl rings carry / -Me groups and the other is either a 2,3- or 3,4-catecholate. Although the metals are not directly bridged in these complexes, they are held at fixed Mo - Fe distances. EPR spectroscopy at 4K shows distance-dependent static dipolar coupling between the Mo and Fe centers. At 77 K the dipolar coupling is modulated by rapid relaxation of the Fe center. Coordination of two A-methylimidazoles to the Fe centers produce S = l/2)Fe-(5 = 1/2)mo coupled systems that are not only... 

Not only a wide range of cations complex with the catechol system of urushiol but the borate anion also undergoes quite strong association. Thus urushiol together with Aliquat 336 was valuable for the solvent extraction of this anion probably through the formation of 1 1 and 2 1 chelates (ref.293). 

Co = Catechol oxidase He = Hemocyanin Tyr = Tyrosinase MePy2 = Al,Al-bis(2-pyridylethyl)methylamine TACN = 1,3,5-triazocyclononane TMPA = Tris[(2-pyridyl) methyl]amine XYL-0 = a, a -bis[Al,Al-bis(2-pyridylethyl) amino]-m-xylene-2-olate XYL = a, a -bis[Al,Al-bis(2-pyri-dylethyl)amino]-m-xylene XYL-R = Meta substituted a,a bis[Al,Al-bis(2-pyridylethyl)amino]-m-xylene N3 = N, N, Al, Al -Tetrakis-(2-pyridin-2-yl-ethyl)-propane-1,2-diamine N4 = Al,Al,Al, Al -Tetrakis-(2-pyridin-2-yl-ethyl)-butane-1,2-diamine N5 = Al,A,lV, Al -Tetrakis-(2-pyridin-2-yl-ethyl)-pentane-1,2-diamine HB(3,5-Pr2pz)3 = Hydrotris(3, 5-diisopropyl-l-pyrazolyl) borate XAS = X-ray absorption spectroscopy EXAFS = Extended X-ray absorption fine structure rR = resonance Raman. 

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