2-Hydroxy-2-phenylazo

Hydroxy-4-phenylazo-benzofurazan setzt sich mit Diazomethan unter 1,3-dipolarer Cycloaddition um94 ... 

Methods for the histochemical localization of /3-glucuronidase, employing the /3-glucuronides of 1-naphthol, 6-bromo-2-naphthol, l-(2-hydroxy-phenylazo)-2-naphthol, and 8-quinolinol as substrates, have been critically examined by Burton and Pearse.146 The last-named substrate gave the least unsatisfactory results, and the technique compares not unfavorably with histochemical methods for other enzymes. 

Wang et al. [43] used poly(alamine hydrochlodride) (PAH) as polycation and poly] l-[4-(3-carboxy-4-hydroxy-phenylazo) benzenesulphonamido]-l,2-ethane-diyl, sodium salt] (PCBS) as polyanion. Wavelength shifts greater than 60 nm have been observed after deposition about 60 nm-thick multilayer film and record shifts of 40 nm have been observed with 25 nm films in an LPG of A = 116 pm and a length of L = 50 mm. 

The Chemicaly3.bstractIndexis 2,7-naphthalene-disulfonic acid, 4-amino-5-hydroxy-3-[[4 -[(4-hydroxyphenyl)azo] [l,l -biphenyl]-4-yl]azo]-6-(phenylazo)-, disodium salt. 

The reaction of 6-amino-5-(l,2-diethoxycarbonylhydrazino)pyrimidines with enamines represents another convenient method for the preparation of pteridines. Fusion of 5-(l,2-diethoxycarbonylhydrazino)-2,4,6-triaminopyrimidine (281) with an excess of mor-pholinocyclohexene leads to 2,4-diaminotetrahydrobenzo[g]pteridine, and with the morpholinoenamine (282) from 17/3-hydroxy-5a-androstan-3-one regioselective condensation to the fused pteridine (283) takes place in almost quantitative yield (equation 101) (71CC83). 6-Amino-5-nitroso- and 6-amino-5-phenylazo-pyrimidines react similarly, imitating the Timmis-type reaction (72CPB1428). 

Acyl-, 4-alkoxycarbonyl- and 4-phenylazo-pyrazolin-5-ones present the possibility of a fourth tautomer with an exocyclic double bond and a chelated structure. The molecular structure of (138) has been determined by X-ray crystallography (Table 5). It was shown that the hydroxy group participates in an intramolecular hydrogen bond with the carbonyl oxygen atom of the ethoxycarbonyl group at position 4 (8OCSCII21). On the other hand, the fourth isomer is the most stable in 4-phenylazopyrazolones (139), a chelated phenyl-hydrazone structure. 

Naphthol-4-sulfonic acid, l-(2-hydroxy-3-methyi-l-phenylazo)-... 

Allura red AC (E 129, FD C Red No. 40, Cl Eood Red 17) is a mono azo dye that consists essentially of 6-hydroxy-5-(2-methoxy-5-methyl-4-sulfophenyl) azo-2-naphtalenesulfonic acid sodium salt (or disodium 2-hydroxy-l-(2-methoxy-5-methyl-4sufonato-phenylazo)-naphthalene-6-sulfonate). The calcium and potassium salts are also permitted. 

Brilliant Black BN (E 151, Black PN, Cl Food Black 1) is a bis azo dye tetrasodium 4-acetamido-5-hydroxy-6-[7-sulfonato-4-(4-sulfonato-phenylazo)-l-naphthylazo]-l,7-naphtha-lene-disulfonate. The calcium and potassium salts are also permitted. It is a black powder or granules, soluble in water, sparingly soluble in ethanol, with a maximum absorption in water at 570 mn = 530). It is not... 

Dyes based on 4-phenylazo-l-naphthol (6) have been used extensively to study azo/hydrazone tautomerism since they exist as an equilibrium mixture of both the azo and hydrazone tautomers.8 However, they are of little use commercially and of no use whatsoever for metal complex azo dyes since the hydroxy group is not ortho to the azo group so these cannot act as chelating ligands. 

Amidoblack 4-Amino-5-hydroxy-3-[4-nitrophenyl)azo]-6-(phenylazo)-2,7-naphtalenedisulphonic acid disodium salt... 

C17H13N3O3 l-Phenylazo-2-hydroxy-3- naphthylhydroxamic acid Exttaction-photomett ic V 3... 

Ru(H20)2(azpy)2] " (azpy=2(phenylazo)pyridine).Thereagent[Ru(HjO)j(azpy)2] V Na(Br03)/aq. 0.2M phosphate buffer/60°C oxidised carbohydrates thus 1-decyl-P-D-maltoside at the Cg-primary hydroxy function gave a carboxylic group, and the decyl chain was split from the maltose unit [858, 859]. 

Zur Veretherung von 7-Hydroxy-4-phenylazo-benzofurazan mit Diazomethan zu 7-Methoxy-... 

Hydroxy-5-methyl-phenylazo)-2.3,5,6-tetrafluor-pyridin 66% Schmp. 172-173°... 

NH-CO-CH3 2,4-(OCH3)2 anilinocarbonyl) -phenylazo -2- ( 5-chlor-2.4-dimeth-oxy-anilinocarbonyl) -3-hydroxy-... (Zers.)... 

Hydroxy- 7-(4-nilro-phenylazo)-5-suifo-chinolin 83% Schmp. > 340 ... 

Hydrazono-1-oxo- bzw. 2,6-Bis-[hydrazono]-l-oxo-cyclohexan werden durch Tetra-chlor-l,4-benzochinon zu 2-Hydroxy-azobenzol bzw. 2,6-Bis- phenylazo]-phenol dehy-driert. Die Methode kann auch auf in 4-Stellung mit Carboxy- oder Methyl-Gruppen substituierte Derivate angewendet werden2 ... 

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