Nitration bases

An interesting example of the effectiveness of different reagents for 0-nitration can be seen during the synthesis of neo-inositol-based nitrate ester explosives. l,4-Dideoxy-l,4-dinitro-neo-inositol (15), a compound readily prepared from the condensation of nitromethane and glyoxal in the presence of base,undergoes conversion to the tetranitrate ester (16) on... 

The rate coefficient (k2 enc) for the collision of two species is given by 8RT/3Z (where Z is the viscosity of the medium at the reaction temperature), the Smoluchowski equation. This is the maximum possible rate of reaction, which is controlled by the rate at which the two reacting species diffuse together. For nitration in >90% H2S04, where nitric acid is completely ionized, if exclusively the free base nitrates the rate coefficient (k2 fb) would equal k2 obs KJhx (where Ka is the ionization constant of the base, and hx the acidity function that it follows). Thus, if k2 fb> k2 enc free base nitration is precluded, but if... 

Little is known quantitatively about substituent effects in the nitration of derivatives of azanaphthalenes. In preparative experiments 4-hydroxy-quinoline, -cinnoline, and -quinazoline give the 6- and 8-nitro compounds, but with nitric acid alone 4-hydroxyquinoline and 2,4-di-hydroxyquinoline react at C(3).31 With nitric acid, 4-hydroxycinnoline still gives mainly 4-hydroxy-6-nitrocinnoline, but some of the 3-nitro compound can also be isolated.81 51 The change of orientation with reagent could be due to a change to free-base nitration in the more weakly acidic medium, or to the occurrence in nitric acid of nitration via nitrosation.31... 

A further analysis of rate profiles obtained for free base nitrations is possible. If allowance is made for the decrease in the concentration of the reactive species, the resulting rate profile should have a slope similar to that for a conjugate acid. Thefree base rate coefficient 2(fb) is defined by Eq. (3.9) and can be calculated by Eq. (3.10), in which m is the slope of the substrate protonation correlation. 

The species involved in nitration of 2-methylindole with excess concentrated nitric acid is not known, but is probably the free base after the entry of the first nitro group. The final product is 2-methyl-3,4,6-trinitroin-dole and a variety of intermediate mono- and dinitro compounds can be obtained nitrodeacylation can also be used (65JOC3457) (Scheme 8.4). These results again show that electron-supplying substituents in the 2-position preferentially activate the 6-position. Evidence that these results relate to free base nitration comes from nitration of compounds 8.39-8.42 in nitric acid/sulfuric acid (65T1923). The conjugate acid is most probably... 

With acetyl nitrate, the 1,10- (11.90) and 4,7-phenanthrolines (11.91) gave the 3- and 2-nitro products, respectively this was attributed to an addition-elimination mechanism (73RC2255), though it is possible here that direct nitration occurs on the free base. Nitration of 3,4-dihydro-4-methyl-3-oxo-4,7-phenanthroline (11.92) occurs in the 2-position (58-JCS825). This is the site that can conjugate with the nitrogen lone pair and substitution there involves the least interruption of benzenoid character in the transition state. 

Corrected for isomer distribution and statistical factor. b 0, free base is reacting species. u +, conjugate acid is reacting species. d Free base nitration is assumed. 

The solution contains a feeble base (nitrate ion) and a weak acid (ammonium ion). The acid is stronger than the base, so the solution is somewhat acidic ... 

In the reaction with bases, nitrates and nitrites are formed. 

Nozaki Y. and Yamamoto Y. (2001) Radium 228 based nitrate fluxes in the eastern Indian Ocean and the South China Sea and a silicon-induced alkalinity pump hypothesis. Global Biogeochem. Cycles 15, 555-567. 

Dimethyl phthalate is incompatible with strong acids or bases, nitrates, and strong oxidizing agents. 

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