Quinolines nitro

Little is known quantitatively about substituent effects in the nitration of derivatives of azanaphthalenes. In preparative experiments 4-hydroxy-quinoline, -cinnoline, and -quinazoline give the 6- and 8-nitro compounds, but with nitric acid alone 4-hydroxyquinoline and 2,4-di-hydroxyquinoline react at With nitric acid, 4-hydroxycinnoline... 

Among the aromatics, it was found that 4-nitroquinoline N-oxide [56-57-5] is a powerful carcinogen producing malignant tumors when painted on the skin of mice (80). It was further estabUshed that the 2-methyl, 2-ethyl, and 6-chloro derivatives of 4-nitro quinoline oxide are also carcinogens (81). 

FrielA,nderSynthesis. The methods cited thus far all suffer from the mixtures which usually result with meta-substituted anilines. The use of an ortho-disubstituted benzene for the subsequent constmction of the quinoline avoids the problem. In the FrieWider synthesis (52) a starting material like 2-aminoben2aldehyde reacts with an CX-methyleneketone ia the presence of base. The difficulty of preparing the required anilines is a limitation ia this approach, but 2-nitrocarbonyl compounds and the subsequent reduction of the nitro group present a usehil modification (53). 

The reaction of /V-henzylideneaniline (19) with alkynes leads to quinolines substituted in the heterocychc ting (56). Except for benzyhdenes bearing nitro substituents, the reaction occurs in good yield and under mild conditions. The method appears capable of elaboration. 

Corrosion Inhibitors. Steel-reinforcing wire and rods embedded in concrete containing quinoline or quinoline chromate are less susceptible to corrosion (72) (see Corrosion and corrosion control). Treating the surface of metals with 8-hydroxyquinoline [148-24-3] makes them resistant to tarnishing and corrosion (73). Ethylene glycol-type antifreeze may contain quinoline, 2-chloro-, 4-amino-, 8-nitro-, or 8-hydroxyquinoline to prevent corrosion (74). 

Quinoline, 4-methyl-5,6,7,8-tetrahydro-synthesis, 2, 471 Quinoline, 2-methylthio-3-nitro-3-substituted... 

Quinoline, 5-nitro-oxidation, 2, 210 synthesis, 2, 318 Quinoline, 6-nitro-nitration, 2, 318 Quinoline, 7-nitro-nitration, 2, 318 synthesis, 2, 318 Quinoline, 8-nitro-... 

Quinoline-3-carboxylic acid, l-methyl-6-nitro-4-oxo-antibacterial activity, 1, 180 Quinoline-3-carboxylic acid, 2-oxo-3-substituted... 

Quinolin-4-one, (R)( +)-2-methyl-1,2-dihydro-synthesis, 2, 422 Quinolin-4-one, 3-nitro-synthesis... 

Ewins has synthesised both substances from m-methoxybenzoic acid, which on nitration gave 2-nitro-3-methoxybenzoic acid, and this, on reduction and treatment with methyl iodide, yielded damasceninic acid, which, by esterification with methyl alcohol, furnished damascenine. Kaufmann and Rothlen found that the additive product of 8-methoxy-quinoline and methyl sulphate, on oxidation with permanganate, yields formyldamasceninic acid, MeO. CgH3(NMe. CHO). COOH, which can be transformed into damasceninic acid by warming with dilute hydrochloric acid. ... 

The first condensation is conducted selectively on a variety of 3-ketoesters and a-formylesters. The first step works well on most simple anilines even when sterically congested and is mostly affected by basicity. Formation of intermediate 3 is problematic when strong electron-withdrawing groups (EWG) are attached to the aniline (e.g., nitro). The cyclization step is promoted thermally in inert solvents as well as using acidic solvents at elevated temperature. When there exists an opportunity to form isomers on cyclization (e.g., m-substituted anilines) a mixture of the 5- and 7-substituted quinolines usually results. 

The stabilizing influence in the hydrated cation is the amidinium resonance. If a solution of the cation is neutralized, a short-lived hydrated neutral molecule (4) (half-life 9 sec at pH 10) is obtained with an ultraviolet spectrum similar to that of the hydrated cation but shifted to longer wavelengths (5 m/ ). Supporting evidence can be derived from the anhydrous nature of the cation of 4-nitroiso-quinoline (pK 1.35), in which the nitro group has a similar electronic influence to that of the ring nitrogen atom N-I in quinazoline and where amidinium resonance is not possible. 

The order NO2 > Cl, which is known for the reactions of nitro-activated aromatic compounds, is also found for pyridine and quinoline derivatives. In the reaction of 2-chloro-4-nitroquinoline with methoxide ion, only the 4-methoxide derivative is formed, as shown by gas-chromatography, whereas 2,4-dichloroquinoline yields a mixture of the isomeric chloro-methoxy derivatives in comparable amounts. ... 

The A-oxidation of 3-chloropyridazines increases their reactivity toward methoxide and sulfanilamide anions.The reactivity of 4-chloro- or 4-nitro-quinoline and of chloropyridines toward methoxide ion and piperidine is less than that of the corresponding A-oxides (see Tables II and XI, pp. 270 and 338). The activating effect of the A-oxide moiety in 3-halopyridine A-oxides is greater than that of a nitro group, and in fluoroquinoline A-oxides the activation is transmitted to resonance-activated positions in the adjoining rings. 

The accelerative effect of London forces of attraction between a nucleophile and nearby substituents has been investigated in quinoline and benzene derivatives by Bunnett and co-workers, ii7b, 307 In 2-, 4-, and 6-arylsulfonyl-3-nitrochlorobenzene, Loudon and Shulman found that arylmercaptide ion, presumably through this effect, displaced the arylsulfonyl group while methoxide or ammonia displaced the nitro or chloro group. 

To derive the maximum amount of information about intranuclear and intemuclear activation for nucleophilic substitution of bicyclo-aromatics, the kinetic studies on quinolines and isoquinolines are related herein to those on halo-1- and -2-nitro-naphthalenes, and data on polyazanaphthalenes are compared with those on poly-nitronaphthalenes. The reactivity rules thereby deduced are based on such limited data, however, that they should be regarded as tentative and subject to confirmation or modification on the basis of further experimental study. In many cases, only a single reaction has been investigated. From the data in Tables IX to XVI, one can derive certain conclusions about the effects of the nucleophile, leaving group, other substituents, solvent, and comparison temperature, all of which are summarized at the end of this section. 

---