Preparation tetranitromethane

Acetone, Nitrotion. Krauz Stepanek(Ref 1) attempted to prepare tetranitromethane by nitration of acetone, but failed. Instead, they obtained (after treating the resulting product with a silver salt) a very expl solid claimed to be Ag salt of "acetylmethylnitrolic acid , also called a-nitro-a-isonitroso-acetone. 

In addition to the initial reaction between nitric acid and acetic anhydride, subsequent changes lead to the quantitative formation of tetranitromethane in an equimolar mixture of nitric acid and acetic anhydride this reaction was half completed in 1-2 days. An investigation of the kinetics of this reaction showed it to have an induction period of 2-3 h for the solutions examined ([acetyl nitrate] = 0-7 mol 1 ), after which the rate adopted a form approximately of the first order with a half-life of about a day, close to that observed in the preparative experiment mentioned. In confirmation of this, recent workers have found the half-life of a solution at 25 °C of 0-05 mol 1 of nitric acid to be about 2 days. ... 

Cyclic and acyclic silyl enol ethers can be nitrated with tetranitromethane to give ct-nitro ketones in 64-96% yield fEqs. 2.42 and 2.43. " The mechanism involves the electron transfer from the silyl enol ether to tetranitromethane. A fast homolydc conphng of the resultant cadon radical of silyl enol ether with NO leads tn ct-nitro ketones. Tetranitromethane is a neutral reagent it is commercially available or readdy prepared. " ... 

Safety aspects of the preparation from halotrinitromethanes or tetranitromethane by treatment with methyl iodide are improved by use of an aprotic solvent (DMF, DMSO or HMPA) in diethyl ether or carbon tetrachloride at 30-60°C. 

Cyclic nitroalkenes are prepared from cyclic ketones via nitration of vinylstannanes with tetranitromethane in DMSO, as shown in Eq. 2.36, where DMSO is a critical choice of solvent for replacing tin by nitro at the unsaturated carbon. The conversion of ketones to vinylstannanes... 

Nitroisoxazolines were prepared from ALalkoxy-3,3-dinitroisoxazolidines by thermally induced P-elimination. For example, isoxazolidines 42 synthesized by a three-component reaction of tetranitromethane with two equivalents of alkenes 41, were converted into isoxazolines 43 by heating in boiling chlorobenzene <06S706>. 

The synthesis and chemistry of iodonium thiophene derivatives have been studied <00AM133, 00TL5393>, for example, the preparation of 46 involved the ipso substitution of 2-stannylthiophene 45 <00CC649>. A similar ipso substitution of 2-stannylbenzo[b]thiophene 47 with tetranitromethane gave 2-nitrobenzo[ >]thiophene (48) . 

However, in our opinion, the rigorous assignment of products to covalent nitronic esters rather than to their structural isomers, which are true nitro compounds or ionic salts, is a more important and complex problem This problem involves difficulties, because ambident anions of nitro compounds (which are evident precursors of nitronates) have comparable O- and C-nucleophilicities and, therefore, the resulting substrates can belong to any of the above mentioned series. Incorrect structure assignments of derivatives of polynitro compounds prepared from tetranitromethane were made in former studies. In addition, the structures of nitronates assigned to some products in early studies, should not have been accepted without the use of modem spectral methods. 

As useful as tetranitromethane is as a charge-transfer nitrating agent, it is generally too unreactive to effect the comparable electrophilic nitration of most aromatic donors, except the most electron-rich ones. Thus in order to make the direct comparison between the photochemical and thermal nitration of the same ArH, we now turn to the A-nitropyridinium acceptor (PyNOj) as the alternative nitrating agent (Olah et al., 1965, 1980). For example, PyNO can be readily prepared as a colourless crystalline salt, free of any adventitious nitrosonium impurity, and used under essentially neutral conditions. Most importantly, the electrophilic reactivity of this... 

Condensed 1,3,2-dioxazoles are produced by the reaction of A-phenyliminophosphorane and 9,10-phenanthreno-and 1,2-naphthoquinones (Scheme 7). Photochemical addition of tetranitromethane to aromatic compounds is still in use for the preparation of 1,3,2-dioxazolidines 22 and 23 but in low yields. 

For the preparation of tetranitromethane on the laboratory scale Chattaway s method [68] is commonly used. It consists in treating acetic anhydride with fuming nitric acid at room temperature or below. After a few days the homogeneous solution is poured into water, causing the oily tetranitromethane to separate. 

Nitroform is obtained when acetylene is introduced into nitric acid it may also be prepared from tetranitromethane. 

Tetranitromethane can itself be prepared in good yield by the nitration of acetic anhydride or isopropanol using cone. HN03. The synthesis requires very exact control of the reaction conditions and is not without danger. 

Of all the women chemists, Phyllis Violet McKie24 of the University College of Wales, Bangor, one of Orton s protegees, seems to have been the most productive during the war period. McKie was part of the team at Bangor producing paraldehyde.25 In addition, she devised a new method for the preparation of the explosive tetranitromethane for the Ministry of Munitions, and she studied methods of preparation of saccharin and vanillin for war purposes.26 Orton reported back to the War Committee ... 

Various a-nitro ketones, widely used as synthetic intermediates, have been prepared by reaction of silyl enolates with tetranitromethane in the dark at room or low temperature or under photochemical conditions. The highly coloured solutions are due to intermolecular 1 1 electron donor-acceptor complexes formed between the enolate and tetranitromethane. The formation of similar vividly coloured complexes with electron acceptors such as chloranil, tetracyanobenzene and tetracyanoquinonedimethane readily establishes silyl enolates as electron donors. The formation of radical cations as reactive intermediates has been confirmed. 

When aldehydes are prepared by ozonolysis, exactly the correct amount of ozone must be added, because excess ozone converts aldehydes to acids and peracids. In addition, alcohols, ethers, double bonds, or other functional groups present in the molecule may be attacked. This brings up the problem of determining when to stop the ozonolysis reaction. The theoretical amount of ozone may be added, but several cases are recorded in which more than one molar equivalent of ozone is required to cleave one double bond. One may stop when ozone appears in the effluent gas from the reactor. However, preliminary experiments have shown that at this low temperature ozone begins to overflow very soon after the reaction has started. A more useful method has been to stop the ozonolysis when the reaction mixture no longer shows unsaturation. This may be detected qualitatively by the use of bromine in carbon tetrachloride, tetranitromethane, etc. An infrared method makes it possible to follow quantitatively the rate of disappearance of trans double bonds and to locate the end point more exactly. The method was applied to the ozonolysis of stigmastadienone with good results. 

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