Nitro groups s. a. under replacement

The anion of nitromethane is particularly reactive in S l reactions. Various kinds of tertiary nitro groups are replaced by a nitromethyl group on treatment with the anion of nitromethane (Section 7.1).49 2-Iodoadamantane reacts with the anion of nitromethane in the presence of acetone enolate (entrainment reaction) under irradiation of a 400-W UV lamp to give 2-ni-tromethyladamantane in 68% yield, (see Eq. 5.32).50a 1-Iodoadamantane also reacts with the anion of nitromethane in a similar way.50b... 

This fragmentation mode was minor or absent under the following conditions (a) in the absence of an ortho-nitro group on the S-aryl ring, as in compounds 169b, k, 1 (b) when the AT-arylidene group was replaced by a iV-alkylidene, as in compounds 170 and 171 (c) when the imine functional group was saturated, as in compound 172. 

In 1866 Kekule [1291 described the reaction of nitrobenzene with bromine t 250°C which under pressure yielded tetra- and hexabromobenzene [130], thus the replacement of the nitro group by bromine occurred. Later it was found 11311 that chlorobenzene was the main product when acting with chlorine on (nitrobenzene at 375°C in 46 s contact time with only a small proportion of chloronitrobenzenes. The substitution of nitro groups in m-dinitrobenzene by chlorine in gas phase at 200-300°C appears to be a commercial method of manufacturing m-diclilorobenzene [132]. Ponomarenko [133] studied this reaction and found the yield to be 92%. He also stated that aromatic nitro com-jpounds are transformed into chloro derivatives by acting on nitro compounds f with carbon tetrachloride at 220—310°C under pressure. 

A mixture of nitrobenzene, cupric carbonate, and NaO/f in50%-ethylenediamine heated 4 hrs. at 90° under 15 p.s.i.g. CO in a shaking apparatus aniline. Conversion ca. 100%. - By this method, nitro groups can be reduced selectively, especially in compounds containing other reducible groups such as double bonds or carbonyl groups. If CO is replaced by the reaction is too slow to be of preparative value. H. R. Appell, J. Org. Chem. 32, 2021 (1967). 

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