Nitro-substituted naphthalenes

The reactions of nitrobenzene and 1- and 2-nitro-substituted naphthalenes with ethyl isocyanoacetate in the presence of DBU were found to proceed very slowly [81, 82], and yields of the target isoindoles proved to be extremely low, with conversion of the starting nitro compounds not exceeding 10% (Scheme 44). 

Naphthalene-1,8-dicarboxylic add, its nitro-substituted derivatives, and naphthalene-1,4,5,8 tetracarboxylic acid, on treatment with sulfur tetrafluoride at 0 C, undergo dehydration to form quantitatively the corresponding anhydrides [218, 221] Unsubstituted and mononitrated monoanhydndes react further at 200-250 °C to give derivatives of 1,1,3,3-tetrafluoro-l// naphtho[I,8 c,d]pyran Dinitronaphthalene-l,8-di-carboxyhc acid anhydndes and naphthalene 1,4,5,8 tetracarboxylic acid dianhydnde give the respective tetra- and octafluoroethers only in the presence of an excess of anhydrous hydrogen fluoride [221] (equabons 113 and 114)... 

Grignard reagent.80 Competition by nucleophilic aromatic substitution was not observed unless the only active position(s) was (were) substituted with a leaving group, as in the reaction of l-methoxy-2-nitro-naphthalene which gave 1 -alkyl-2-nitronaphthalenes in 73-95% yields.81 The use of Me3SiCH2MgCl (Peterson reagent) provides an entry to nitro-substituted benzyl anion intermediates, as shown in the example of Scheme 9.82... 

An analogous series of dicationic species have been proposed in the reactions of nitro-substituted arenes in superacid. For example, 2-nitro-naphthalene (212) reacts in superacid to give the arylated product (214) in good yield (eq 62).74... 

The 2,i-orientation of an azine-nitrogen and a leaving group is characterized by activation which is exceptionally poor compared to other resonance activations. The poor activation, which is often grossly underrated, is still substantial relative to the substituted naphthalene 10 -10 -fold increase in the rates of alkoxylation and of alkylamination. The properties of 2,3,-orientation come into play in ail 3-substituted naphthalenes or azanaphthalenes which bear an azine-nitrogen or activating substituent in the 2-position (Section IV, A, 2). This orientation is subject to such a decrease in activation due to the relatively poor stabilization of charge in the ortho,ortho-quinoid structure (352) that 3-substituted isoquinolines and 2-nitro-naphthalenes are less reactive than 2-substitnted pyridines and nitrobenzenes (Section IV, A, 2). Insertion of a 3-aza moiety into a... 

The nitro substitution products of naphthalene are easily prepared by the action of nitric acid on the hydrocarbon. By such direct nitration the product obtained is alpha-nitro naphthalene. This is proven by the following series of reactions. Nitro-naphfhalene by reduction yields amino naphthalene, naphthylamine, which by the diazo reaction yields hydroxy naphthalene, naphthol. Now the naphthol so obtained is identical with the one resulting from the phenyl vinyl acetic acid synthesis (p. 768) and this must be the alpha compound. 

When anthracene is treated with nitric acid instead of yielding nitro substitution products as do benzene and naphthalene it becomes oxidized to a compound known as anthraquinone, the composition of which is C14H8O2 and which may be reduced back to anthracene by heating with zinc dust. The relationship in composition between anthracene and anthraquinone is the same as between benzene and benzoquinone and between naphthalene and naphthoquinone. 

The (x-substituted naphthalenes, like substituted benzenes, are ihpst commonly prepared by a sequence of reactions that ultimately goes back to a nitro compound (Sec. 30.8). Preparation of / -substituted naphthalenes, on the other hand, cannot start with the nitro compound, since nitration does not take place in the j3-position. The route to /3-naphthylamine, and through it to the versatile dia-zonium salts, lies through /9-naphthol. /9-Naphthol is made from the /3-sulfonic acid it is converted into /8-naphthylamine when heated under pressure with ammonia and ammonium sulfite (the Bucherer reaction, not useful in the benzene series except in rare cases). 

The acylation of 2-substituted naphthalenes usually occurs at l-(a-) position [2]. But there are some exceptions where it can give rise to different kind of isomers by changing the reaction conditions [9]. 2-Methoxy naphthalene (2-MON) has been shown to be acetylated mostly either in l-(a)-position to yield l-acetyl-2-methoxynaphthalene or at 6-(P)-position to yield 2-acetyl-6-methoxynaphthalene depending on the catalyst and solvent systems used [10]. The a-isomer is rep)orted in most of the cases. But in the case of AICI3 catedysed acylation of 2-MON in presence of certain solvents, especially nitro compounds, a solvated nitro complex is formed by which acylation at the P-position is preferred [3]. 

In general, the a SCS are similar to those of corresponding 1- and 2-substituted naphthalenes (20, 49, 70-72). There are only a few exceptions. For example, the a-methyl effect in 7-methyl-coumarin is considerably larger than for all other isomers (11.2 vs. 8.3-9.7 ppm) (20). Despite the similarity of the a-hydroxy effects in 4-hydroxycoumarin and 1-naphthol (22.4 and 23.4 ppm, respectively), the corresponding methoxy effects are quite different (22.6 and 27.6 ppm, respectively). In 6-cyano- and 7-nitrocoumarin the a SCS are smaller by ca. 3 ppm than in 2 cyano- and 2-nitro-naphthalene. Again, there is no satisfactory explanation. 

Fischer-Hepp rearrangement The nitros-amines of aromatic secondary amines when treated with hydrochloric acid give nuclear substituted nitrosoamines. Among the benzene derivatives, if the para position is free the -NO group displaces the hydrogen atom there in naphthalene derivatives it enters the 1-position ... 

Fluoronaphthalene [321-38-0] is prepared from 1-naphthylamine by the Balz-Schiemaim reaction in 52% yield or by diazotization in anhydrous hydrogen fluoride in 82% yield. Electrophilic substitution occurs at the 4-position, eg, nitration with fuming nitric acid in acetic acid gave 88% yield of l-fluoro-4-nitro-naphthalene [341 -92-4]. 

Draw Lewis structures (or a series of Lewis structures) for the intermediate ions formed by addition of N02 to naphthalene at the 1 and 2 positions (nitro-naphthalenium ions ). On this basis, are you able to anticipate which intermediate is likely to be the more stable Examine the energies of 1-nitronaphthalenium and 2-nitronaphthalenium ions to see which ion is actually more stable. Which substitution product should be favored Is this the same product anticipated by inspection of naphthalene s HOMO Is it the observed product ... 

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. 

MNN is obtained in 3—5% yield by the nitration of naphthalene and is present at this level in coml MNN. It is best prepd by indirect methods for example, by the removal of an amino group from an appropriately substituted nitro-naphthylamine. The amine is treated with Na nitrite and acid to form the diazonium salt which is replaced with a H atom by redn with EtOH (Ref 7). It may also be prepd by treatment of 6-nitro-l, 2,3,4-tetrahydronaphthalene with Br to form a dibromo compn (probably the 1,4-isomer), followed by removal of two moles of H bromide by distn in the presence of base (Ref 10). 2-Naphthalenediazonium fluoroborate... 

Tetradehydrodianthracene undergoes 4 + 2-cycloaddition with electron-deficient dienes such as 1,2,4,5-tetrazines.263 The Diels-Alder reactions of [3.3 ortho-anthracenophanes witli A-(p-nitro, chloro, or methoxy-substituted phenyl)malehnides yield approximately equal quantities of inside and outside adducts.264 The photooxidation of bulky water-soluble 1,4-disubstituted naphthalenes with singlet oxygen yields both the expected 1,4- and the unexpected 5,8-endoperoxides.265... 

Base-catalyzed condensation (Equation 31) of 4,6-dinitro-l-tosylindoline with salicylaldehyde or 2-hydroxy-naphthalene-l-carbaldehyde is accompanied by intramolecular nucleophilic substitution for one of the nitro groups to give benzo- and naphthooxepino[4,3,2-crf indoles, respectively <2003IZV725>. 

---