Nitro group substitution

I). These are saturated hydrocarbons having terminal polynitro groups, and may be prepd by treating saturated hydrocarbons, having at feast one terminal nitro group substituted in one terminal Me group, with tetranitromethane... 

SNAr substitutions of activated aromatic halides, especially aromatic fluorides, provide useful means for the construction of aromatic diethers or amines. Primary and secondary amines react with l, 2-dihalo-4,5-dinitrobenzene to give nitro group substitution at room temperature. The halogen substituents on the ring remain unsubstituted and can be used in further transformation (Eq. 9.5).8... 

Table 16 shows the results of the same reaction under different pressures between atmospheric pressure (10-4 GPa) to 0.78 GPa. At atmospheric pressure, nitro-group-substitution product, 18a, and o-mono- and p-monosubstitution products 19a and 20a were obtained in a total yield of 7.4% recovering 92% of the starting pentachloride 16. When the pressure was raised, the yields of these monosubstitution products increased at higher pressures di- and trisubstitution products appeared and this trend continued in the reactions under pressures above 0.60 GPa, affording higher yields of the trisubstitution product 23a. These results indicate that the second substitution occurred at the pressure... 

In a manner similar to that of l-tosyl-4,6-dinitroindoline (see Scheme 28, Section 2.2.1), 4,6-dinitrobenzofuran undergoes condensation with salicylic aldehyde under basic conditions followed by nitro group substitution/cycliza-tion to afford a mono nitro compound with peri-fusion of the benzofuran ring in 68% yield (2005CHE796). 

A nitro group substituted in phenol should increase the acid constant by virtue of the inductive effect of the electronegative group (with N+ attached to the ring) moreover, in the ortho and para positions there would occur an additional resonance effect, due to the contribution of structures such as the following ... 

The value of the electron-transfer rate constant (102—105s ) is dependent upon the number and position of the nitro groups substituted on the aromatic ring. 

High pressure (0.6 GPa) isfAr of 2,3,5,6,-tetrachloronitrobenzene (119) with various primary and secondary amines 120 gives nitro-group-substitution products 121 together with mono-, and dichloro substitution products 122-127 (Scheme 7.31). The ratio of substitutions of the nitro group and chlorine atom is affected by the bulkiness of the amines. ... 

The only recorded instance of a nitration of an oxazole derivative where the nitro group substitutes a ring hydrogen is the formation, in 97% yield, of 5-nitro-2-dimethylamino-4-(p-nitrophenyl) oxazole (166) from... 

Mechanisms involving radicals have been proposed for the nitro group substitution of />-dinitro-benzene by 2,6-disubstituted phenoxide to give diphenyl ethers [226] and for the reactions of dini-trobenzenes with polyfluoro-alkoxides and -thioalkoxides [227]. 

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