Nitro form

In solution, a nitronic acid either isomerizes slowly into its more stable nitro form or undergoes some kreversible transformation. The isomerization occurs sufficiently slowly that it can be measured by conductometric or halometric methods. 

B. Methylenedi(nitro form amide). Abs nitric acid (19ml) is added dropwise with stirring to a suspension of 5 g of crude me thylenedi form amide in 19ml of acet anhyd at 10—15°, the soln held... 

N 17.72% OB to C02 —70.53% liq bp 53-56° at 1 mm RI 1.4380. Prepn is by reacting nitro-form with vinyl isopropylether. The ether burns readily and deton with a heavy blow Refs 1) Beil, not found 2) Anon, Synthesis of New Explosives Propellants ,. Quarterly Progress Rept No 4, US Rubber Co, Passaic, Contract Nord 10129 (1948)... 

The nitro form is much more stable than the aci form in sharp contrast to the parallel case of nitroso-oxime tautomerism, undoubtedly because the nitro form has resonance not found in the nitroso case. Aci forms of nitro compounds are also called nitronic acids and azinic acids. 

The enantiomeric reduction of 2-nitro-l-phenylprop-l-ene has been studied in a range of Gram-positive organisms including strains of Rhodococcus rhodochrous (Sakai et al. 1985). The enantiomeric purity of the product depended on the strain used, the length of cultivation, and the maintenance of a low pH that is consistent with the later results of Meah and Massey (2000). It has been shown that an NADPH-linked reduction of a,p-unsaturated nitro compounds may also be accomplished by old yellow enzyme via the flcf-nitro form (Meah and Massey 2000). This is formally analogous to the reduction and dismutation of cyclic enones by the same enzyme (Vaz et al. 1995), and the reductive fission of nitrate esters by an enzyme homologous to the old yellow enzyme from Saccharomyces cerevisiae (Snape et al. 1997). 

Protonated aci-nitro forms of C-glycosylnitromethanes that are resistant to the Nef reaction in aqueous acidic media undergo a modified Nef reaction in acidified ethanol. These reaction conditions allowed the... 

It was mentioned above that acetalic nitroxyl radicals produced by addition of a-alkoxyalkyl radicals to tetranitromethane (TNM) undergo a spontaneous heterolysis with the carbon center being oxidized and TNM reduced (to nitro-form anion (NF ) and NOj). In order to see the addition-elimination sequence with acyclic a-alkoxyalkyl radicals there have to be two (electron-withdrawing relative to methyl) hydrogens at Q. Even one alkyl group at Q is sufficient to make khs > 10 s and therefore too fast to measure. If, however, an alkyl group which is inductively deactivated is introduced at Q, the k values fall in the... 

Free radicals may substitute C-H bonds. Gaseous NO2 (0.3 bar) has been tested with solid barbituric acids (40a-c). Reactions with 100% yield arise after 4 h exposure and the dried products (80 °C) assume the acz-nitro forms 258a-c [19] (Scheme 37). A very large field for preparative use appears to be opened with these and related waste-free reactions. The couple product N2O3 can be collected for further use. 

Preparation of this compd is probably by nitration of trinitroethanol prepared from nitro-form and formaldehyde... 

Ref 2), later from the 2-bromo ester and silver nitrate in acetonitrile (Ref 3) . by oxidizing 1-nirropopatrfe-l with nitric acid followed by esterification (Re/ 4), by reacting silver nitro-form with the 2-bromo ester (Ref 5) and by reacting the 2-bromo or iodoester with nitric acid (Ref 6)... 

Delft University of Technology and the University of Delaware) is hydrazinium nitroformate [N2H5.C (N02)3 Structure (4.2)] a salt of hydrazine (N2H4) and nitro-form or trinitromethane [HC(N02)3], reported to have been discovered in 1951. Of course, this is made without the use of N205. It is prepared as a precipitate [74] by acid-base reaction between nitroform and hydrazine, Equation 4.18. 

Ammonium Nitro form. See Ammonium Trinitrons ethane under Methane and Derivatives... 

Nitromethane was proposed as a probe molecule of basic sites on catalyst surfaces. The nitro form is in equilibrium with a small amount of the aci tautomer. Kheir and Haw (165) demonstrated that the aci tautomer was deprotonated on MgO and CaO to form chemisorbed aci anion (Scheme... 

An interesting property of this ion is that when solutions of it are acidified, an unstable, rather strongly acidic isomer of nitromethane (called the aci form) is produced, which slowly reverts to the more stable nitro form ... 

It had been established several decades ago that the reaction of 1-chloro-l-ni-troethane with sodium nitrite in aqueous-alcohol medium is second order overall and first order in each reactant (Hawthorne 1956). 1-Deutero-l-chloro-l-nitroethane reacts more slowly than its lighter isotopomer. This means that the kinetic isotopic effect is observed. The reaction proceeds only in moderately alkaline media in strongly alkaline media it does not take place. Only those geminal halo nitro compounds, which carry hydrogen in the geminal position, can undergo the conversion. Based on these facts, Hawthorne (1956) suggested the Sn2 substitution preceded by the isomerization of the initial substrate into the aci-nitro form ... 

The intramolecular hydrogen abstraction has been largely developed for the case of the nitro group [22,37], and is well known for some derivatives of o-nitrotoluene, for o-nitrobenzyl alcohols, ethers and esters [38-40] as well as on the acetals of o-nitrobenzaldehyde [41], With these compounds, the nn (singlet or triplet) state abstracts a hydrogen and the biradical relaxes to the aci-nitro form (the first intermediate is actually observed in bicyclic systems where formation of the nitronic acid is sterically hindered) [41], which under basic conditions dissociates to the corresponding anion [42],... 

---