Polynitroaliphatic compounds

The chemical properties of the nitro group have important implications for the synthesis of more complex and useful polynitroaliphatic compounds and so these issues are discussed in relation to energetic materials synthesis. 

Polynitroaliphatic compounds have not found widespread use as either commercial or military explosives. This is perhaps surprising considering the high chemical and thermal stability of compounds containing internal em-dinitroaliphatic functionality. In fact, many polynitroaliphatic compounds are powerful explosives, for example, the explosive power of... 

Nitronate salts can react with alkyl halides to yield polynitroaliphatic compounds with varying degrees of success. The main by-products of these reactions arise for competitive 0-alkylation. Alkyl nitrates are formed as by-products when the nitroform anion is used in these reactions. ... 

The reactions of alkyl halides with the silver salt of dinitroacetonitrile have been shown to be of limited use for the synthesis of polynitroaliphatic compounds. These reactions give a mixture of C-, N- and O-alkylation products with product distribution highly dependent on the nature of the substrate. ... 

In a related reaction to that described above, nitronate salts have been reacted with a-chloronitroalkanes as a route to polynitroaliphatic compounds. 2,3-Dimethyl-2,3-dinitrobutane (48) is formed from the reaction of the nitronate salt of 2-nitropropane (46) with 2-chloro-2-nitropropane (47). A modification to the original process uses nitronate salts in the presence of iodine to form an a -iodonitroalkane in situP ... 

Primary and secondary nitroalkanes, and substrates containing terminal em-dinitroaliphatic functionality, have one or more acidic a-protons, a consequence of inductive and resonance effects imposed by the nitro group. As a result, such compounds can behave like carbanions and participate in a number of addition and condensation reactions which are typical of substrates like ketones, aldehydes, and /S-ketoesters. Such reactions are extremely useful for the synthesis of functionalized polynitroaliphatic compounds which find potential use as explosives, energetic oligomers and plasticizers. 

The conjugate 1,4-addition of nitronate anions and other nucleophiles to a-nitroalkenes constitutes an important method for the synthesis of polynitroaliphatic compounds. ° Nitroform (112) reacts with nitroethene (135) and 2-nitropropene to yield 1,1,1,3-tetranitropropane (136) and 1,1,1,3-tetranitrobutane respectively. A number of examples of additions of 1,1-dinitroethane, 1,1-dinitropropane and 1,1-dinitrobutane to nitroalkenes have been reported. Feuer and co-workers reported the synthesis of 1,3,3,6,6,8-hexanitrooctane (137) from the reaction of 1,1,4,4-tetranitrobutane (30) with nitroethene under basic conditions. 

Both the Henry reaction and the reverse demethylolation are synthetically useful in the chemistry of polynitroaliphatic compounds. The Henry reaction is commonly used to mask the natural chemistry of an aliphatic nitro or terminal em-dinitro group by removing the acidic a -proton(s). In Section 1.7 we discussed the conversion of Q ,ty-dinitroalkanes to their bis-methylol derivatives before subjecting them to oxidative nitration and subsequent demethylolation with base, a procedure which results in the formation of Q ,Q , y, y-tetranitroalkanes. ... 

Many of the nitronate salts of polynitroaliphatic compounds, particularly salts of gem-nitronitronates, exhibit properties similar to known primary explosives. Consequently, the storage of such salts is highly dangerous. Treatment of these nitronate salts with formaldehyde yields the corresponding methylol derivative via the Henry condensation. These methylol... 

The stability of polynitroaliphatic compounds to acids, bases and nucleophiles is often linked to the presence of an acidic o -proton(s) which may allow various resonance structures to lead to rearrangement or decomposition. Additionally, the presence of two or more nitro groups on the same carbon atom greatly increases the susceptibility of the carbon-nitrogen bonds to nucleophilic attack. 

Alkylations and other reactions using polynitroaliphatic alcohols as nucleophiles usually require Lewis acid catalysts. A comprehensive review of the chemistry of fluoronitro compounds. 

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