Quinoline, 4-nitro-, amination

Data for several ammine-halo, am-mine-ethylenediamine, halo-nitro-amine, halo-nitro-triammine, chloro-alkil-ammine, alcohol-ammine, tetra-amino, pyridine-chloro, picoKne-chloro, quinoline - chloro, phenanthr oline - amm -ine-chloro, and so on, complexes have been compiled in [159, 160]. Some regularities have been found, for example, of Pt halo-complexes decreases with the increasing atomic number of the halogen atom the successive substitution of NH3 for chloro ligands causes the decrease of... 

The rate of amination and of alkoxylation increases 1.5-3-fold for a 10° rise in the temperature of reaction for naphthalenes (Table X, lines 1, 2, 7 and 8), quinolines, isoquinolines, l-halo-2-nitro-naphthalenes, and diazanaphthalenes. The relation of reactivity can vary or be reversed, depending on the temperature at which rates are mathematically or experimentally compared (cf. naphthalene discussion above and Section III,A, 1). For example, the rate ratio of piperidination of 4-chloroquinazoline to that of 1-chloroisoquino-line varies 100-fold over a relatively small temperature range 10 at 20°, and 10 at 100°. The ratio of rates of ethoxylation of 2-chloro-pyridine and 3-chloroisoquinoline is 9 at 140° and 180 at 20°. Comparison of 2-chloro-with 4-chloro-quinoline gives a ratio of 2.1 at 90° and 0.97 at 20° the ratio for 4-chloro-quinoline and -cinnoline is 3200 at 60° and 7300 at 20° and piperidination of 2-chloroquinoline vs. 1-chloroisoquinoline has a rate ratio of 1.0 at 110° and 1.7 at 20°. The change in the rate ratio with temperature will depend on the difference in the heats of activation of the two reactions (Section III,A,1). 

T. Urbanski and Kowalski [34] have studied the explosive properties of pyridine perchlorate as well as quinoline and its nitro derivative perchlorates. Due to the introduction of a nitro group the sensitiveness to shock of the quinoline perchlorate increased, but to a smaller extent than the authors had previously observed with primary aromatic amines. The introduced nitro group markedly favoured the increase of explosive strength of the perchlorates (Table 116). 

The oxidising agent usually employed is the nitro-compound corresponding to the amine, e.g., nitrobenzene when aniline is the base for p-toluidine, p-nitrotoluene serves, and so on. Arsenic acid, however, can be generally employed, and gives better results. The reaction is capable of very wide application nitro-, halogen-, hydroxy-, carboxy-quinolines can all be obtained from the corresponding amines the amino-naphthalenes also react. Diamines yield the so-called phen-anthrolines. (B., 16, 2519 23, 1016.)... 

Oxidative methylamination of 2-, 3-, 4-, 5-, 6-, 7-, and 8-nitroquinolines at —7 °C leads, as could be expected, to similar results as obtained in the oxidative amination (93LAC823). In general, the methylamination differs from the oxidative amination in several aspects (a) the reaction occurs faster than the amination, due to the higher temperature at which the reaction is carried out, (b) gives higher yields, (c) the site specificity is less than observed in the amination, as it appears by the sometimes occurring formation of mixtures of (methylamino)nitroquinolines, and even in the case of 5-nitro-quinoline formation of bis(methylamino)-5-nitroquinolines (Table III). 

An important use of the traditional Skraup synthesis is to make 6-methoxy-8-nitroquinoline from an aromatic amine with only one free ortho position, glycerol, the usual concentrated sulfuric acid, and the oxidant arsenic pentoxide. Though the reported procedure uses 588 grams of As2Os, which might disconcert many chemists, it works well and the product can be turned into other quinolines by reduction of the nitro group, diazotization, and nucleophilic substitution (Chapter 23). 

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