8-Hydroxyquinoline, reaction with

Diethyl succinate, reaction with 3 hy droxycinchomnic acid to yield 3-hydroxyquinoline, 40, 56 N,N-Diethyl-2,2,2-trichloroacetamide, 41, 21... 

Hydroxybenzaldehyde, condensation with hydantoin, 43, 49 5-(/>-Hydroxybenzal)hydantoin, 43, 49 3-Hydroxydnchoninic add, 40, 55 reaction with diethyl succinate to yield 3-hydroxyquinoline, 40, 56... 

Aziridine esters are a- and -amino acid derivatives at the same time. A characteristic reaction of a-amino acids is their reaction with triethylboron to give boroxazolidines. We showed that aziridinecarboxylic acids exhibit the expected behavior in their reaction with triethylboron, viz., that they form stable boroxazolidines 34 (Scheme 19) [29]. These boron heterocycles can be reconverted into the free amino acids by treatment with 8-hydroxyquinoline. 

The five-coordinate complexes Ir(CO)(PPh3)2L, where HL = /3-diketone, A-benzoyl-A-phenyl-hydroxylamine, salicylaldehyde, 8-hydroxyquinoline, 2-hydroxybenzophenone, 2-hydroxy-8-methoxybenzophenone, were prepared from [Ir(CO)(PPh3)2Cl].632 The resulting compounds all underwent oxidative addition reactions with Br2. Reaction of [(cod)2IrCl]2 with N-substituted 3-hydroxy-2-methyl-4-pyridine gives the bichelated complex (389). 33... 

Among the most important indirect methods of analysis which employ redox reactions are the bromination procedures for the determination of aromatic amines, phenols, and other compounds which undergo stoichiometric bromine substitution or addition. Bromine may be liberated quantitatively by the acidification of a bromate-bromide solution mixed with the sample. The excess, unreacted bromine can then be determined by reaction with iodide ions to liberate iodine, followed by titration of the iodine with sodium thiosulphate. An interesting extension of the bromination method employs 8-hydroxyquinoline (oxine) to effect a separation of a metal by solvent extraction or precipitation. The metal-oxine complex can then be determined by bromine substitution. 

N,N-Diethyl-N -phenyI-2,2-dichloro-acetamidine, 41, 23 Diethyl succinate, for synthesis of tri-ethyl oxalylsucdnate, 44, 67 reaction with 3-hydroxycinchoninic acid to yield 3-hydroxyquinoline, 40,56... 

SWV has been applied to study electrode reactions of miscellaneous species capable to form insoluble salts with the mercury electrode such as iodide [141,142], dimethoate pesticide [143], sulphide [133,144], arsenic [145,146], cysteine [134, 147,148], glutathione [149], ferron (7-iodo-8-hydroxyquinolin-5-sulphonic acid) [150], 6-propyl-2-thiouracil (PTU) [136], 5-fluorouracil (FU) [151], 5-azauracil (AU) [138], 2-thiouracil (TU) [138], xanthine and xanthosine [152], and seleninm (IV) [153]. Verification of the theory has been performed by experiments at a mercury electrode with sulphide ions [133] and TU [138] for the simple first-order reaction, cystine [134] and AU [138] for the second-order reaction, FU for the first-order reaction with adsorption of the ligand [151], and PTU for the second-order reaction with adsorption of the ligand [137]. Figure 2.90 shows typical cathodic stripping voltammograms of TU and PTU on a mercuiy electrode. The order of the... 

The hydroxyquinoline (39-2) provides the starting material for a quinolone that incorporates a hydrazine function. Reaction of (39-2) with 2,4-dintrophenyl O-hydroxylamine ether (41-1) in the presence of potassium carbonate leads to a scission of the weak N-O hydroxylamine bond by the transient anion from the quinolone the excellent leaving character of 2,4-dinitrophenoxide adds the driving force for the overall reaction, resulting in alkylation on nitrogen to form the hydrazine (41-2). The primary amine is then converted to the formamide (41-3) by reaction with the mixed acetic-formic anhydride. Alkylation of that intermediate with methyl iodide followed by removal of the formamide affords the monomethylated derivative (41-4). Chlorine at the 7 position is then displaced by A-methylpiperazine and the product saponified. There is thus obtained amifloxacin (41-6) [48]. 

Complexes of 8-hydroxyquinoline and chromium(III) have been known for many years.1139 Complexes have been mercurated and the deuterated quinoline isolated.1139 The bromination of chelated 8-hydroxyquinoline proceeds about thirty-five times faster than that of the free ligand.1140 Tris(8-hydroxyquinolinato)chromium(III) absorbs large amounts of hydrochloric, hydrobromic and hydrofluoric acids. Chemical reaction with the complex was considered a more likely explanation than solid solution or clathrate formation, even though more than one mole of acid was absorbed per mole of complex.1141... 

Renault et a/.140 have also observed O- and N-alkylation in the reaction of hydroxyquinoline anions with Me2S04 or RX and TBAB as catalyst to give 116. 

Applebury and Coleman 48) found that biosynthetic enzyme and apoenzyme labeled with 85Zn bound 2-3 zinc ions per dimer at neutral pH but as many as 7 at pH 10.0. Dialysis for 24 hr removes extra zinc, and after 20 days only two remain and the enzyme is active. Thus it appears that the two zinc binding sites that are most readily occupied in the apoenzyme and must be occupied for activity are the ones that most strongly retain zinc ions during dialysis but, on the other hand, most readily lose zinc ions by reaction with 8-hydroxyquinoline-5-sulfonic acid. 

Metal chelates of 8-hydroxyquinoline such as (111) with photoconductive properties are reported to be useful in electrophotographic systems.233 The incorporation of a tin complex into a photo-conductive zinc oxide layer is stated to reduce dark decay . In other words, the electrostatic charge applied to the photoconductor has a longer lifetime. Two of the complexes disclosed for this application are (112) and (113). These compounds are prepared from dibutyltin oxide by reaction with 2-mercaptopropionic add and thioglycolic acid, respectively 234... 

In superacid catalyzed reactions of hydroxyquinolines and isoquinolines, dicationic superelectrophiles were proposed as intermediates in their reactions (see Table 4).35d In order to explain differences in relative reactivities between the isomeric superelectrophiles, the energies of the lowest unoccupied molecular orbitals Ultimo ), the square of the coefficients (c2) at the reactive carbon atoms, and the NBO charges (q) on CH groups were determined by MNDO and DFT computational methods. For example, 8-hydroxyquinoline (85) is found to be more reactive than 6-hydroxyquinoline (87) in the superacid catalyzed reactions with benzene and cyclohexane (eqs 47 -8). 

Other diprotonated acyl-pyridines have likewise been studied.61 In studies of 5-, 6-, 7-, and 8-hydroxyquinolines and 5-hydroxyisoquinoline, dicationic intermediates like 185 (Table 4) were found to be involved in superacid catalyzed reactions with benzene and cyclohexane.59 For example, 8-hydroxyquinoline (187) reacts in CF SOsH-SbFs to generate dications (188 and 189) and undergoes ionic hydrogenation in the presence of cyclohexane (eq 64). Compound 187 also reacts with benzene in suspensions of aluminum halides (eq 65). 

Quinolinium salts have been used in the synthesis of hydroxyquinoline derivatives with KO/Bu in the presence of ultrasound <95SC(25)2999>. Quinolinium salts have been used in cycloaddition reaction with butadiene derivatives to give acridine compounds (Scheme 38) <95SL938>. 

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