Nucleophilic aromatic substitution 6-nitroquinoline

These systems nitrate aromatie eompounds by a proeess of electro-philie substitution, the eharacter of whieh is now understood in some detail ( 6.1). It should be noted, however, that some of them ean eause nitration and various other reactions by less well understood processes. Among sueh nitrations that of nitration via nitrosation is especially important when the aromatic substrate is a reactive one ( 4.3). In reaetion with lithium nitrate in aeetie anhydride, or with fuming nitrie aeid, quinoline gives a small yield of 3-nitroquinoline this untypieal orientation (ef. 10.4.2 ) may be a eonsequenee of nitration following nucleophilic addition. ... 

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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