Benzene derivatives nitro groups

The chlorinated intermediate 255 is eliminated and cycloadds to Cjq, yielding pyrazo-linofullerenes of the structure 257 (Scheme 4.42). The 4-nitrophenyl-group can be replaced by a 4-methoxyphenyl- or a phenyl substituent. In this reaction various aromatics and substituted aromatics are tolerated as residues R (e.g. furan, ferrocene, pyrazole or benzene and substituted benzene). The nitro group of the nitrophenyl residue can be reduced with Sn-HCl to the aniline derivative, which can be further functionalized by amide coupling with acid chlorides [311]. 

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 ... 

Chloramphenicol. Only chloramphenicol and a few closely related analogues fall iato this group. Chloramphenicol, a nitro benzene derivative of dichloroacetic acid, inhibits proteia biosyathesis. 

Nitro and azido. In benzene derivatives, the nitro group is said to rival fluorine and exceed chlorine in replaceability. The reactivity of the nitro group in heterocycles is also very high, and this... 

Sulfonio. Incorporation of this group in azines may present synthetic and stability problems. In benzene derivatives, dimethyl-sulfonio is substantially better as a leaving group than is a nitro or trimethylammonio group. 

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. 

One of the most important derivatives of benzene is nitrobenzene. The nitro group is —NOi. Nitrobenzene is important chiefly because it is readily converted into an aromatic amine, aniline, by reduction. One preparative procedure uses zinc as the reducing agent ... 

By further nitration with more concentrated acid o- and p-nitro-phenols are converted into the same 2 4-dinitrophenol, and finally into picric acid. Polynitro-derivatives of benzene, such as picric acid and trinitrotoluene, can be caused to explode by detonation with mercury fulminate or lead azide. (The formulae of these two compounds should be written.) They are endothermic, i.e. the oxygen of the nitro-group can oxidise carbon and hydrogen within the molecule and heat is liberated. This intramolecular combustion is rather considerable in the case of picric acid, which is decomposed in accordance with the equation ... 

More recently, Kim and coworkers have developed a novel radical alkylation reaction of organic nitro derivatives 16a-d via bis(silyloxy)enamines 17a-d (Scheme 16). This method enables not only P -alkylation to the nitro gronp, bnt also the conversion of the nitro group (16a-d) into an oxime ether fnnctionahty (18a-d). The irradiation of a solntion of 16a-d with iodomethyl phenyl snlfone (or ethyl iodoacetate) and hexamethylditin in benzene at 300 nm give the oxime ethers 18a-d in good yields. 

For a review of this and closely related reactions, see Morrison, in Feuer The Chemistry of the Nitro and Nitroso Groups, pt. 1 Wiley New York, 1969, pp. 165-213, 185-191. For a review of photochemical rearrangements of benzene derivatives, see Kaupp Angew. Chem. Int. Ed. Engl. 1980, 19, 243-275 [Angew. Chem. 92, 245-276). See also Yip Sharma Res. Chem. Intermed. 1989, 11, 109. 

---