Tnaz ones

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

A convenient, one-pot, two-step synthesis of l-azabicyclo[1.1.0]butane (5, R = H) from f -chlorosuccinimide is reported and its application to the synthesis of 133-tnnitroazetidine (TNAZ) is discussed <98SC3949>. Another novel and efficient synthesis of 1-aza-bicyclo[1.1.0]butane (5, R = H) and its derivatives is from 23-dibromopropylamine. The bicyclic 5 (R = H) is also useful in the synthesis of the pendant group of a ip-methylcarbapenem antibiotic <99TL3761>. The reaction of 5 (R = Et and Ph) with tosyl chloride and tosyl azide are described <98T15127,99H131>. 

TNAZ was first synthesized in 1983 and has a strained four-membered ring backbone with both C-nitro and nitramine (N—N02) functionalities. There are various routes that yield TNAZ all of which consist of several reaction steps. One possible synthesis of TNAZ is shown in Figure 1.6. It starts from epichlorohydrine and lBu-amine. As far as the author of this book is aware, there has been no wide-spread use for TNAZ so far. 

Fig. 1.7 Molecular structures of 5-nitro-l,2,4-triazol-3-one (NTO), 1,3,3-trinitroazetidine (TNAZ), hexanitrohexaazaisowurtzitane (CL-20), octanitrocubane (ONC) and 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX).

The first evidence of secondary dissociation appears in the time-of-flight spectrum of m/e = 54. This ion corresponds to a loss of a total of three NOj groups from TNAZ. Since the ion giving the m/e = 100 differs from the m/e = 54 ion by one NO2 group, it is reasonable to expect that the faster m/e = 5A signal is due to secondary decomposition of the heavier fragment (produced by Reaction 1) via toss of NO2... 

For RDX the distribution peaks at zero, but for TNAZ the peak near 5 kcal/mol. The RDX data may have been obscured in the low energy part of the secondary NOj loss due to the many other channels participating in the decomposition of this molecule. One may speculate that the secondary loss of NO2 in RDX ahio proceeds over a small barrier, which would explain the noticeably higher translational energy released in the second NOj loss step compared to the first. 

Molecular beam studies provide a useful compliment to bulk phase decomposition studies. The knowledge of which steps are the initial ones in the decomposition will allow the results of bulk phase studies to be analyzed with an eye toward understanding the secondary bimolecular reactions and the role of condensed phase chemistry. The molecular beam studies are also useful in conjunction with theoretical efforts. The dynamics of TNAZ decomposition should be theoretically tractable and when available they will be easily tested against molecular beam results. 

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