Trinitromethane

Vinyl etheis serve as a source of vinyl groups for transvinylation of such compounds as 2-pyrrolidinone or caprolactam (240,241). Compounds such as carbon tetrachloride (242) or trinitromethane (243) can add across the double bond. 

Polynitroparaffkis are stronger acids than the corresponding mononitroparaffins. Thus 1,1-dinitroethane has an ionization constant of 5.6 x 10 in water at 20°C trinitromethane is a typical strong acid with an ionization constant ki the range of 10 to 10 . Neutralization of these substances occurs rapidly, and they may be titrated readily. 

In addition to neutralization, prolonged action of alkaline reagents can effect oxidation—reduction and extensive decomposition. 1,1-Dinitroparaffins and trinitromethane are more stable than are mononitro compounds during neutralization and subsequent regeneration, and therefore more rigorous experimental conditions are permissible. 

Nitroform. Same as Trinitromethane see under Methane and Derivatives in this Vol... 

One attempted reaction of trinitromethane with impure ketone caused an explosion at refrigerator temperature. 

Frozen mixtures of trinitromethane -2-propanol (9 1) exploded during thawing. The former (of positive oxygen balance) dissolves exothermally in the alcohol, the heat effect increasing directly with the concentration above 50% w/w. Traces of nitric acid may also have been present. 

Contact of acetylene with the cone, acid in presence of mercury salts forms trini-tromethane, explosive above its m.p., 15°C. Subsequent addition of sulfuric acid produces tetranitromethane, a powerful oxidant of limited stability, in high yield. See Trinitromethane, also Tetranitromethane... 

For example, the use of diazomethane makes it possible to synthesize the corresponding O-methyl nitronates from dinitromethane (18), trinitromethane (19), and two isomeric TV-methyltetrazolyldinitromethanes (20) (Scheme 3.8, Eq. 1)... 

In reactions of certain alkyl halides with salts of polynitromethanes, C-alkyla-tion can also be diminished and target O-nitronates can be prepared in satisfactory yields (21, 22) (Scheme 3.8, Eq. 2). Of special note is the study by Kim and Adolph (22), who prepared numerous nitronates by alkylation of salts of dinitromethane, cyanodinitromethane, and trinitromethane with a representative series of a-chloro-substituted (including functionalized) ethers. 

Very interesting results were obtained by Russian researchers in alkylation of the Ag salt of trinitromethane with alkyl halides (Scheme 3.9) (23-25). 

In this manner, the Ag salt of trinitromethane is involved in cascade reactions with branched alkyl halides to give unexpected products. 

To the contrary, only C-alkylation of the trinitromethane anion with these intermediates is observed (32, 33) if the cations in the ion pair are stabilized by one or two alkyl substituents at the a-carbon atom (Eq. 2). 

It has been expected that trinitromethane derivatives of the general formula (NC>2)3C — M (M is K, Cs, SiMe3, or SnBuj) can generate dinitrocarbene through solvolysis, and the latter can react as a 1,3-dipole with some olefins (74). However, a next study (75) demonstrated that this interpretation of the processes is erroneous at least for M=SiMe3. Attempts to detect nitrocarbenes in cycloaddition reactions during thermolysis or photolysis of aliphatic nitrodiazo compounds also failed (76). 

In addition to conventional generation of carbenes from nitrodiazo compounds (22) (79), target intermediates C can be prepared by oxidation of functionalized AN CH2XNO2 with phenyliodonium diacetate. The reactions of Rhodium intermediates with certain olefins afford the corresponding cyclopropanes (23). The cycloaddition reaction was performed in the presence of a catalyst. (The successful synthesis of nitrocyclopropanes from trinitromethane derivatives and nitroacetic ester was also documented (81)). 

Approximately at the same time, Shevelev and coworkers studied the reactions of trinitromethane and 1,1-dinitroethane salts with RCOC1 (R=Me or Ph) and detected the corresponding acyl nitronates on the basis of decomposition products and by trapping with various E—X reagents (222) (Scheme 3.64). 

The chemistry of O-acyl derivatives of trinitromethane was studied in more detail. By analogy with O-silyl ethers of trinitromethane, for intermediate (120) (Scheme 3.103, Eq. 1) it was suggested (222a) that the reaction involves elimination of acetyl nitrate to form the very unstable N-oxide A, which adds acetyl chloride to give derivative (121). Saponification of the latter affords isolable oxime (122). 

Scheme 3.103). In these experiments, a representative series of trinitromethane derivatives (NC C-E was isolated in various yields.

Trimethylsilyl ether of trinitromethane decomposes at ambient temperature (176) to give very unstable trimethylsilyl nitrite. Another decomposition product, nitronitrile oxide, can be trapped in low yield as the adduct with triphenylphos-phine. 

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