USOO5693794A United States Patent (19) 11 Patent Number: 5,693,794 Nielsen 45 Date of Patent: Dec. 2, 1997 54). CAGED POLYNTRAMINE COMPOUND R.D. Gilardi. “The Crystal Structure of CHNO, a Heterocyclic Cage Compound." Acta Chystallographica, 75 Inventor: Arnold T. Nielsen, Santa Barbara, vol. B28, Part 3 (Mar. 1972), pp. 742-746. Calif. A.T. Nielsen and R.A. Nissan, "Polynitropolyaza Caged 73) Assignee: The United States of America as Explosives-Part 5." Naval Weapons Center Technical Pub represented by the Secretary of the lication 6692 (Publication Unclassified), China Lake, Ca. , Navy, Washington, D.C. Mar. 1986, pp. 10-23. (21) Appl. No.: 253,106 Primary Examiner-Richard D. Lovering 22 Filed: Sep. 30, 1988 Attorney, Agent, or Firm--Melvin J. Sliwka; Stephen J. Church 51 .................. CO7D 259/00 52 . 540/554; 14992; 540/556 (57) ABSTRACT 58 Field of Search ...................................... 54.0/554, 556 A new compound, 2.4.6.8, 10.12-hexanitro-2,4,6,8,10,12 56 References Cited8. hexaazaisowurtzitane12-hexaazatetracyclo[5.5.0.0'dodecane) (2,4,6,8,10.12-hexanitro-2,4,6,8,10, is disclosed PUBLICATIONS and a method of preparation thereof. The new compound is useful as a high energy, high density explosive. J.M. Kliegman and R.K. Barnes. "Glyoxal Derivatives-I 3. rgy, high Conjugated Aliphatic Dimines From Glyoxal and Aliphatic Primary Amines." Tetrahedron, vol. 26 (1970), pp. ONN NNO 2555-2560. ONN NNO J.M. Kliegman and R.K. Barnes. "Glyoxal Derivatives-II. Reaction of Glyoxal With Aromatic Primary Amines,” Jour nal Organic Chemistry, vol. 35 (1970), pp. 3140-3143. J.M. Edwards, U. Weiss, R.D. Gilardi, and LL. Karle "For mation of a Heterocyclic Cage Compound From Ethylene diamine and Glyoxal," Chemical Communications, (1968), pp. 1649-1650. 28 Claims, No Drawings 5,693,794 1 2 CAGED POLYNTRAMNE COMPOUND or less than 0.1 mole-equivalent of formic acid (relative to one mole-equivalent of amine) is employed. The reaction BACKGROUND OF THE INVENTION time is accelerated by heating, but yields of hexabenzyl 1. Field of the Invention hexaazaisowurtzitane (HBIW) are not increased; excessive 5 heating is undesirable. Other solvents may be employed This invention relates to polyaza caged molecules. More (methanol, ethanol, propnol) but offer no advantages over particularly, the invention relates to polyaza caged mol acetonitrile. ecules having the hexaazaisowurtzitane caged ring system. The structure of hexabenzylhexaazaisowurtzitane including one with nitro groups attached to each nitrogen (HBIW): atom, and a method for producing the same, useful as an explosive. O 2. Description of the Related Art CHsCHN T NCHCHs Known polynitramines such as 1,3,5-trinitro-1,3,5- CsCHN NCHCHs hexahydrotriazine (RDX) and 1,3,5,7-tetranitro-1,3,5,7- tetraazacyclooctane (HMX) are high-energy, high-density 15 explosive compounds (R. Meyer, “Explosives.” Third CsCHN NCHCH5 edition, VCH Publishers, Weinheim, Germany, 1987). They can be prepared by nitrolysis of hexamine with nitric acid is supported by its "Hand "CNMR and mass spectra. The and other similar procedures. Stable polynitramines having X-ray crystal structure of the corresponding hexa(4- energy and density greater than that of HMX were unknown methoxybenzyl)hexaazaisowurtzitane, confirms the struc until the present synthesis of a new class of explosives ture of the ring system. described as caged polynitramine. Several other benzylamines have been successfully con densed with glyoxal to produce substituted hexabenzyl SUMMARY OF THE INVENTION hexaazaisowurtzitanes (with comparable yields), including 25 4-methoxy-, 3,4-dimethoxy-, 4-methyl-, 4-isopropyl-, According to this invention, 2.4.6.8.10.12-hexanitro-2,4, 6.8.10.12-hexaazaisowurtzitane (HNTW) is prepared start 2-chloro-, and 4-chlorobenzylamines. ing with benzylamine and glyoxal which are condensed in a The second isolated intermediate compound in the reac suitable solvent in the presence of a catalyst to produce tion sequence leading to 2.46.8.10.12-hexanitro-2,4,6,8.10, hexabensylhexaazaisourtzitane(HBIW). The hexabenzy 12-hexaazaisowurtzitane (HNTW) is 4,10-dibenzyl-2.6.8, hexaazaisourtzitane (HBIW) is reductively acylated in the 30 12-tetraacetyl-2,4,8,8.10.12-hexaazaisowurtzitane (TAIW). presence of a catalyst in a second step to produce diben It is prepared by reductive acetylation of pure hexabenzyl zyltetraacetylhexaazaisowurtzitane (TAIW). Finally, in the hexaazaisowurtzitane (HBIW) in acetic anhydride solvent last step, dibenzyltetraacetylhexaazaisowurtzitane (TATW) with hydrogen (Pd/C, 1 to 50 psi, -40° to 30° C. 2 to 24 is sequentially debenzylated and nitrated to produce 2.4.6, hours) using a Parr shaker. For maximum yields, the reaction 35 requires an acid promoter. Acids such as HSO4, HCl, or 8, 10.12-hexanitro-2,4,6,8,10,12 hexaazaisowurtzitane HBr (not HI) may be added directly to the reaction mixture (HNTW). before hydrogenation is started. Best results have been DESCRIPTION OF THE PREFERRED obtained with H.Br. It was found most convenient to intro duce the HBr in the form of bromobenzene, acetyl bromide, EMBOOMENT benzyl bromide, or other bromine containing compounds, The synthesis of the first isolated intermediate compound, which are dehydrohalogenated during the hydrogenation to hexabenzylhexaazaisowurtzitane (HBIW), involves conden form the H.Br. The HBr reacts with the acetic anhydride to sation of benzylamine with glyoxal (40% aqueous solution) form acetyl bromide. The concentration of HBr is critical; in aqueous acetonitrile or methanol solvent with formic acid maximum yields were obtained at HBr concentrations of catalyst at 0° to 250° C. The best yield obtained (81%) 45 about one-eighth the number of moles of hexabenzyl requires slow addition of the aqueous glyoxal (1.0 mole hexaazaisowurtzitane (HBIW). The amount of hydrogena equivalent) to a solution of benzylamine (slightly more than tion catalyst, type of catalyst, and concentration of palla 2 mole-equivalents) and formic acid (slightly more than 0.2 dium on the carbon support have been varied. Palladium on mole-equivalent) in aqueous acetonitrile, while keeping the charcoal is preferred over palladium metal alone. The cata temperature at 0° to 250° C. The optimum addition time for SO lyst gives best results when generated by reduction of the aldehyde under these conditions is about one hour. After palladium hydroxide on carbon (Pearlman's catalyst) and addition of all the glyoxal solution is complete, the reaction used in a ratio of about one-fourth the weight of hexaben mixture is allowed to stand at ambient temperature (250° C) zylhexaazaisowurtzitane (HBIW). Dry palladium on char overnight (16 to 18 hours) to complete the formation of the coal (3-20%) may also be used but gives lower yields product which rapidly precipitates from the reaction mixture 55 (40-50%). The reaction is continued until hydrogen uptake in rather pure form. The reaction to form hexabensyl ceases (about 6 hours), but is usually continued overnight. hexaazaisourtzitane (HBIW) is virtually over within a few The solid product, dibenzyltetraacetylhexaazaisowurtzitane hours. Prolonged standing may produce slightly higher (TAIW), is unaffected by the prolonged reaction time. The yields without altering the purity of the product. The hexa isolation of the product involves cooling the reaction mix benzylhexaazaisowurtzitane (HBIW)is isolated by suction ture to 25° C. ( if an exotherm has occurred), followed by filtration, followed by washing with cold acetonitrile or filtration of the catalyst mixed with most of the product. methanol and drying in air. The yields of the unrecrystallized Some of the product remains in the acetic anhydride filtrate. product are 80 to 81%. The crude product is recrystallized The product (mixed with catalyst) may be recovered by from boiling acetonitrile to produce colorless crystals with a extraction of the mixture with boiling chloroform. The acetic melting point of 153° to 157° C. (90% recovery). 65 anhydride solution is concentrated under reduced pressure Organic acid catalysts other than formic acid may be and the residue triturated with acetonitrile to yield the employed, such as acetic acid; the yield is decreased if more dibenzyltetraacetylhexaazaisowurtzitane (TAIW) product. 5,693,794 3 4 The total yield of solid product is about 60-65%. The compound may be recrystallized from acetonitrile or chlo ONN NNO roform. The crude product is quite pure and usually may be used for the next step without further purification. The ONN NNO structure of dibenzyltetraacetylhexaazaisowurtzitane (TAIW): ONN NNO CHCON NCOCH O is supported by its "H NMR spectrum and established by CHCON NCOCH X-ray crystallography. A hemihydrate of the alpha-form, d=1.96 g/cm, may be isolated by crystallization from 70% nitric acid. Crystallization of the product from benzene also CHCHN NCHCHs leads to an anhydrous beta-form, d=1.98 g/cm. Occasion ally the crude hexanitrohexaazaisowurtzitane (HNTW) is 15 isolated as a sulfolane adduct which is readily decomposed in boiling water to yield sulfolane-free hexanitrohexaazai is supported by its "H NMR, mass spectra and chemical sowurtzitane (HNTW). behavior, (conversion into dinitrosotetraacetylhexaazai The compound, 24.8,8.10.12-hexanitro-2,48.8.10.12 sowurtzitane and dinitrotetraacetylhexaazaisowurtzitane in hexaazaisowurtzitane (HNTW), may be prepared by carrying structure number 2, above, CHCH=NO and NO out the three-step procedure set forth in the following respectively; the X-ray crystal structure of the latter com example. pound has been established). EXAMPLE The final reaction sequence leading to the fully nitrated solid explosive compound, 2,4,6,8,10,12-hexanitro-2,4,6,8. 25 Step 1 Preparation of 2,4,6,8,10,12-hexabenzyl-2,4,6,8.10, 12 10.12-hexaazaisowurtzitane (HNIW), proceeds from the hexaazatetracyclo[5.5.0.00"dodecane (2.4.6.8, 10.12 precursor 4.10-dibenzyl-2.6.8, 12-tetraacetyl-2,4,8,8,10,12 hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane) (HBIW).