Quinoline i-oxide

These arguments were originally applied to the 4-nitration of 2,6-lutidine i-oxide and quinoline i-oxide, and use of the data available... 

Because of these difficulties, special mechanisms were proposed for the 4-nitrations of 2,6-lutidine i-oxide and quinoline i-oxide, and for the nitration of the weakly basic anilines.However, recent remeasurements of the temperature coefficient of Hq, and use of the new values in the above calculations reconciles experimental and calculated activation parameters and so removes difficulties in the way of accepting the mechanisms of nitration as involving the very small equilibrium concentrations of the free bases. Despite this resolution of the difficulty some problems about these reactions do remain, especially when the very short life times of the molecules of unprotonated amines in nitration solutions are considered... 

Ochiai and Okamoto showed that nitration of quinoline i-oxide in sulphuric acid at o °C gave 5- and 8-nitroquinoline i-oxides with a trace of the 4-isomer, but that at 60-100 °C 4-nitration became overwhelmingly dominant. The orientation depends not only upon temperature but also upon acidity, and kinetic studies (table 8.4 table 10.3) show that two processes are occurring the nitration of the free base (vil, R = O at C(4), favoured by low acidities and high temperatures, and the nitration of the cation (vil, R = OH), favoured by high acidities and low temperatures. ... 

Free-Energy Values (AG°, 0.1 kcal moF ) for the Tautomerism of Some Substituted Oxadiazolo[3,4-/ or [3,4-/i]Quinoline V-Oxides 46... 

The electrochemical properties of another series of Cu(I) complexes, based on substituted bipyridine and quinoline derivatives, have been also investigated68 (Fig. 17.31). To stabilize the Cu(I) oxidation state of Cu(I) polypyridine complexes, electron-withdrawing substitutents like esters have been considered. The same effect was also obtained with pyridyl-quinoline and biquinoline complexes, thanks to the increased 7i-accepting properties of the quinoline condensed aromatic ring. 

Figure 141. Molecular structure of PhiSn(S2CO—i-Pr((quinoline /V-oxide).

Pyridine N-oxide forms [Ni(py0)3(NCX)2(H20)] (X = S or Se) and [Ni(pyO)2-(NCS)2(EtOH)], both octahedral, the latter possibly via bridging EtOH.143 Detailed i.r. spectra142 have been reported for [Ni(pyO)6](BF4)2 which contains approximately octahedrally co-ordinated nickel(n) with disordered BF groups.515 The quinoline N-oxide compounds [Ni(qnO)2(NCX)2] (X = S or Se) (/teff 2.93 BM) have electronic spectra consistent with octahedral nickel(n), and as the i.r. spectra indicate terminal N-bonded NCX groups, it was concluded that the (qnO) functions as a bridging ligand.143... 

The reactions between i-dinitrobenzene or 1,3,5-trinitrobenzene, aryl halides, and copper(I) oxide in quinoline 17-19, 21) provide a simple synthesis of nitrobiphenyls uncontaminated by symmetrical biphenyls. These couplings may be related to the Ullmann reaction, the decarboxylative coupling of benzoic acids with aryl halides, and the preparation of ethers from phenols 165). Although no intermediates... 

Furo(S,6-/]quinoIine, 864 Furof2,3-(i< uinoiine 5-oxide, 850 Furo 3,2-c-)quinoline 5-oxide, 850 Furo 2,3-( quinolin-4-one, 1194 Furo[2,3-A]quinolin-2-one, 992 Furo(2,3-/r]quinolin-2-one, 992 Furo(3,2-c lquinolin-4-one, 818, 914, 1214, 1281... 

Chemical Properties. - Thermolysis of thiazolinediones (123) in toluene at 100°C gives 4-R1C H CCS)NC0 (R =Me,Cl) which reacted with a, B-unsaturated aldehydes in a Diels-Alder fashion. Quinoline 1-oxides (124 R=H,i -Me,4-MeO,4-morpholino,3-Br) react readily with 2-phenyl-2-thiazolin-4-one in Ac20 to give the corresponding 5-(2-quinolyl)thiazolinones (125). Similar results were... 

Kobayashi, Y. Kumadaki, I Taguchi, S. Organic fluorine compounds. VI. Preparations and reactions of (trifluoromethyl)quinoline 7V-oxide. Chem. Pharm. Bull. 1969, 77(11), 2335-2339. 

Bromide or stoichiometric Silver(I) Oxide, respectively. In many cases, one or both of the aromatic species can be heteroaromatic such as pyridine, furan, thiophene, quinoline, oxazole, thia-zole, or indole. Symmetrical biaryls have been prepared in excellent yields by the Pd(Ph3P)4-catalyzed homocoupling of ArBr/I under phase transfer conditions. ... 

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