Extensive theoretical studies of a new energetic material: Tetrazino‐tetrazine‐tetraoxide (TTTO)

[1,2,3,4]Tetrazino‐[5,6‐e]‐[1,2,3,4]tetrazine‐[1,3,5,7]tetraoxide (TTTO, C₂N₈O₄) was suggested to be a possible candidate of high energy density materials (HEDM). The most stable conformation of TTTO is a planar structure with C_2h symmetry. Using various high‐level ab initio methods including Gaussian‐n, Complete Basis Set, Full Coupled Cluster, and W1U models of chemistry together with density functional theory based models, the enthalpies of formation of TTTO at 0 K and standard state were calculated precisely. Moreover, the rovibrational and nuclear magnetic resonance properties were predicted as well. The solid state TTTO was studied using the crystal packing models with the Dreiding force‐filed and the plane‐wave periodic local‐density approximation density functional theory. Three stable polymorphous cells of TTTO have been found with either P212121 or P21/C symmetry. The high heat of formation (>200 kcal/mol), the high density (>2.0 g/cm³), the planar nonpolar electronic structure, and the perfect oxygen balance lead TTTO be a very promising HEDM with exceptional performance. This work provides the first theoretical support for further experimental synthesis and testing. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009     

New syntheses of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide

New methods were developed for the synthesis of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide from 4-(tert-butyl-NNO-azoxy)-N-nitro-1,2,5-oxadiazol-3-amine or its alkali metal salts and acid anhydrides (or chlorides) in the presence of strong acids. The yield of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide in acetic anhydride in the presence of sulfuric acid or sulfuric anhydride at 20°C in 20 min attained 83%. A general mechanism was proposed for the reactions under study. Acetyl group behaved for the first time as departing group in the synthesis 1,2,3,4-tetrazine 1,3-dioxides, and [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide was obtained in 47% yield from N-[4-(acetyl-NNO-azoxy)-1,2,5-oxadiazol-3-yl]acetamide.     

2,2‐Bis(methoxy‐NNO‐azoxy)ethyl Derivatives of 4,8‐Dihydro‐bis‐furazano[3,4‐b:3′4′‐e]pyrazine: The Synthesis and X‐ray Investigation

The first synthesis of 4,8‐dihydro‐bis‐furazano[3,4‐b:3′4′‐e]pyrazine bearing 2,2‐bis(methoxy‐NNO‐azoxy)ethyl groups has been developed. These compounds are obtained by aza‐Michael reaction of 1,1‐bis(methoxy‐NNO‐azoxy)ethene or its equivalents, such as 2,2‐bis(methoxy‐NNO‐azoxy)ethanol derivatives, with 4,8‐dihydro‐bis‐furazano[3,4‐b:3′4′‐e]pyrazine.     

Synthesis and Thermal Behavior of a Fused,Tricyclic 1,2,3,4‐Tetrazine Ring System

This study presents the synthesis and characterization of a fused, tricyclic 1,2,3,4‐tetrazine ring system. The molecule is synthesized in a three‐step process from 5,5′‐dinitro‐bis,1,2,4‐triazole via a di‐N‐amino compound. Oxidation to form the azo‐coupled fused tricyclic 1,2,3,4‐tetrazine is achieved using tert‐butyl hypochlorite as the oxidant. The di‐N‐amino compound and the desired fused tricyclic 1,2,3,4‐triazine display interesting thermal behavior and are predicted to be high‐performance energetic materials.     

Synthesis and Thermal Behavior of a Fused,Tricyclic 1,2,3,4‐Tetrazine Ring System

This study presents the synthesis and characterization of a fused, tricyclic 1,2,3,4‐tetrazine ring system. The molecule is synthesized in a three‐step process from 5,5′‐dinitro‐bis,1,2,4‐triazole via a di‐N‐amino compound. Oxidation to form the azo‐coupled fused tricyclic 1,2,3,4‐tetrazine is achieved using tert‐butyl hypochlorite as the oxidant. The di‐N‐amino compound and the desired fused tricyclic 1,2,3,4‐triazine display interesting thermal behavior and are predicted to be high‐performance energetic materials.     

Synthesis and structures of pyridoannelated 1,2,3,4-tetrazine 1,3-dioxides

Treatment of 2- and 4-amino-3-(tert-butyl-NNO-azoxy)pyridines with nitrating agents (N₂O₅or NO₂BF₄) afforded the first representatives of pyridoannelated 1,2,3,4-tetrazine di-N-oxides, viz., pyrido[2,3-e][1,2,3,4]tetrazine 1,3-dioxide (9), 7-nitropyrido[2,3-e][1,2,3,4]tetrazine 1,3-dioxide (10), and pyrido[3,4-e][1,2,3,4]tetrazine 2,4-dioxide (11). These compounds were studied by ¹H, ¹³C, and ¹⁴N NMR spectroscopy. The 1:1 complex of compound 10 with benzene was studied by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2471–2477, November, 2004.     

Interaction of 4‐Oxo‐4H‐pyrazolo[5,1‐c][1,2,4]triazin‐1‐ides with Grignard Reagents

Reactions of magnesium 3‐tert‐butyl‐8‐R‐4‐oxo‐4H‐pyrazolo[5,1‐c][1,2,4]triazin‐1‐ides (R = CN, CO₂Et) with AlkMgBr led to nucleophilic additions to either side chain or triazine core, with selectivity being dependent on the nature of substituents, as well as on the solvents used. Previously inaccessible C⁸‐functionalized and C⁴‐functionalized pyrazolo[5,1‐c][1,2,4]triazines and 3‐tert‐butyl‐3‐ethyl‐4‐oxo‐1,2,3,4‐tetrahydropyrazolo[5,1‐c][1,2,4]triazine were synthesized, and their reactivity and spectral data discussed.     

New Aspects of 1,3‐Diphosphacyclobutane‐2,4‐diyls

1,3‐Di(tert‐butyl)‐2,4‐bis[2,4,6‐tri(tert‐butyl)phenyl]‐1,3‐diphosphacyclobutane‐2,4‐diyl was formed from [2,4,6‐tri(tert‐butyl)phenyl]phosphaacetylene and t‐BuLi. In addition, the X‐ray diffraction analysis was carried out, together with theoretical calculations of the structure and NMR data.     

New approach to the synthesis of benzo[e][1,2,3,4]tetrazine 1,3-dioxides

A new approach to the synthesis of benzo[e][1,2,3,4]tetrazine 1,3-dioxides involves the treatment ofN-nitroanilines containing anortho-(tert-butyl-NNO-azoxy) group with phosphoric anhydride or phosphorus pentachloride. The reaction is supposed to proceed through an intermediate diazonium oxide cation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp. 480–484, March, 2000.     

SO2‐Extrusion of an 8‐thiabicylo[3.2.1]octa‐2,6‐diene 8,8‐dioxide and rearrangement of the resulting cycloheptatriene

The reaction of 3,4‐di‐tert‐butyl‐thio‐phene 1‐oxide ( 8 ) with tetrachlorocyclopropene provided 6,7‐di‐tert‐butyl‐2,3,4,4‐tetrachloro‐8‐thia‐bicylo[3.2.1]octa‐2,6‐diene 8‐oxide ( 10 ), which was oxidized to the corresponding 8,8‐dioxide 16 by m‐chloroperbenzoic acid. The thermolysis of 16 in refluxing chlorobenzene, xylene, or octane gave 5‐tert‐ butyl‐1,2‐dichloro‐3‐[(1,1‐dich‐loro‐2,2‐dimethyl)‐pro‐ pyl]‐benzene ( 18 ) with extrusion of SO₂ and 2‐tert‐butyl‐4,5,6‐trichloro‐9,9‐dimethylbicyclo[5.2.0]nona‐1,3,5‐triene ( 19 ) with extrusion of SO₂ and HCl in 73–78% combined yields. On the other hand, the thermolysis of 16 in the presence of triethylamine gave 19 as the sole product in 98% yield. A mechanism that involves the initial formation of 4,5‐di‐tert‐butyl‐1,2,7,7‐tetrachlorocycloheptatriene ( 17 ) is proposed to ex‐ plain the observed products. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:132–222, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20079     

Synthesis of p‐tert‐Butyl‐calix[6] ‐biscrown‐3 via Intramolecular Ring‐closure of 1,4‐Bis (2‐(2‐chloroethoxy) ethoxy) ‐p‐tert‐butyl‐calix[6]arene

With a variation in reaction conditions, 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐calix[6]arene (3) and l,3,5‐tris(2‐(2‐chloroethoxy) ethoxy)‐calix [6] arene (4) or 4 and 4‐chloroethoxyethoxy‐calix[6]crown‐3 (5) were selectively synthesized from p‐tert‐butyl‐calix [6] arene and 2‐(2‐chloroethoxy)ethyltosylate. l,3–4,6‐p‐tert‐butylcalix[6]‐bis‐crown‐3 (6) with (u,u,u,d,d,d) conformation and 1,3–4,5‐p‐tert‐butylcalix[6]‐biscrown‐3 (7) with self‐anchored (u,u, u, u, u, d) conformation were synthesized through an intramolecularly ring‐closing condensation of 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐p‐tert‐butyl‐calix[6]arene (3) in 25% and 15% yield, respectively. Using 5 instead of 3, only 7 was obtained in 65% high yield. 6 and 7 show different complexation properties toward alkali metal and ammonium ions.     

Computer simulation of the crystal structure of tetrazino-tetrazine tetraoxide (TTTO) isomers with one and two independent molecules in the unit cell

Russian Chemical Bulletin - The crystal structure prediction for two isomeric forms of tetrazino-tetrazine tetraoxide (TTTO), viz., [1,2,3,4]tetrazino[5,6-e][1,2,3,4]tetrazine 1,3,6,8-tetraoxide...     

Über die Oxo‐cyclotetraphosphane (PBut)4O1–4

Contributions to the Chemistry of Phosphorus. 243 On the Oxocyclotetraphosphanes (PBu^t)₄O_1–4 Under suitable conditions, the reaction of tetra‐tert‐butylcyclotetraphosphane, (PBu^t)₄, with dry atmospheric oxygen gives rise to the corresponding monoxide (PBu^t)₄O ( 1 ) which has been isolated by column chromatography. The reaction with hydrogen peroxide furnishes a mixture of oxocyclotetraphosphanes (PBu^t)₄O_1–4 consisting of two constitutionally isomeric dioxides (PBu^t)₄O₂ ( 2 a , 2 b ), the trioxide (PBu^t)₄O₃ ( 3 ), and the tetraoxide (PBu^t)₄O₄ ( 4 ), in addition to 1 . According to the ³¹P NMR parameters the oxygen atoms are exclusively exocyclically bonded to the phosphorus four‐membered ring. Which of the P atoms are present as λ⁵‐phosphorus follows from the different low‐field shifts of the individual P nuclei compared with the starting compound. Accordingly, 1 is 1,2,3,4‐Tetra‐tert‐butyl‐1‐oxocyclotetraphosphane, 2 a and 2 b are 1,2,3,4‐Tetra‐tert‐butyl‐1,2‐dioxo‐ and ‐1,3‐dioxocyclotetraphosphane, respectively, 3 is 1,2,3,4‐Tetra‐tert‐butyl‐1,2,3‐trioxocyclotetraphosphane, and 4 is 1,2,3,4‐Tetra‐tert‐butyl‐1,2,3,4‐tetraoxocyclotetraphosphane. When the oxidation reaction proceeds a fission of the P₄ ring takes place.     

Synthesis of tetracyclic system of 2,4‐di(tert‐butyl)‐6,7‐dihydrofuro[2′,3′:3,4]cyclohepta[1,2‐b]indole

For the first time, tetracyclic compounds, namely, furo[2′,3′:3,4]cyclohepta[1,2‐b]indoles were synthesized by recyclization of ortho‐substituted aryldifurylmethanes containing tert‐butyl groups at C5 positions of the furan rings. It was shown that [2‐(benzoylamino)phenyl]bis(5‐tert‐butyl‐2‐furyl)methanes 12 are transformed into tetracycles 15 at room temperature under treatment with POCl₃ in benzene solution containing some drops of water. The reaction proceeds via the intermediate formation of 1‐benzoylamino‐3‐(5‐tert‐butyl‐2‐furyl)‐2‐(4,4‐dimethyl‐3‐oxopentyl)indoles 14 which can be isolated from the reaction mixture. The method is very simple but its application is restricted due to side reactions if electron‐releasing groups are present in 12 . On the other hand, the decrease of electron density on furan ring in the starting compounds (for example, the use of [2‐X‐phenyl]difurylmethanes (where X = tosylamino or hydroxy group) prevents cyclization under the studied reaction conditions. As a result, corresponding ketones are formed as products of recyclization. J. Heterocyclic Chem., (2011).     

Polarity‐Reversal‐Catalyzed Hydrostannylation Reactions: Benzeneselenol‐Mediated Homolytic Hydrostannylation of Electron‐Rich Olefins

Addition of 10 mol‐% of diphenyl diselenide to hydrostannylation reactions involving electron‐rich olefins results in a dramatic improvement in yield. For example, reaction of α‐{[(tert‐butyl)dimethylsilyl]oxy}styrene ( 1 ) with triphenylstannane ( 2a ; 1.1 equiv.) in the presence of PhSeSePh and 2,2′‐azobis[2‐methylpropanenitrile] (AIBN) affords {2‐{[(tert‐butyl)dimethylsilyl]oxy}‐2‐phenylethyl}triphenylstannane ( 3a ) in 95% yield after 2 h. This reaction presumably benefits, by the increased rate of H‐atom transfer, from the in situ generated polarity‐reversal catalyst, benzeneselenol.     

Eight 7‐benzyl‐3‐tert‐butyl‐1‐phenylpyrazolo[3,4‐d]oxazines,encompassing structures containing no intermolecular hydrogen bonds,and hydrogen‐bonded structures in one,two or three dimensions

7‐Benzyl‐3‐tert‐butyl‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₂H₂₅N₃O, (I), and 3‐tert‐butyl‐7‐(4‐methylbenzyl)‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₃H₂₇N₃O, (II), are isomorphous in the space group P2₁, and molecules are linked into chains by C—H...O hydrogen bonds. In each of 3‐tert‐butyl‐7‐(4‐methoxybenzyl)‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₃H₂₇N₃O₂, (III), which has cell dimensions rather similar to those of (I) and (II), also in P2₁, and 3‐tert‐butyl‐1‐phenyl‐7‐[4‐(trifluoromethyl)benzyl]‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₃H₂₄F₃N₃O, (IV), there are no direction‐specific interactions between the molecules. In 3‐tert‐butyl‐7‐(4‐nitrobenzyl)‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₂H₂₄N₄O₃, (V), a combination of C—H...O and C—H...N hydrogen bonds links the molecules into complex sheets. There are no direction‐specific interactions between the molecules of 3‐tert‐butyl‐7‐(2,3‐dimethoxybenzyl)‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₄H₂₉N₃O₃, (VI), but a three‐dimensional framework is formed in 3‐tert‐butyl‐7‐(3,4‐methylenedioxybenzyl)‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₃H₂₅N₃O₃, (VII), by a combination of C—H...O, C—H...N and C—H...π(arene) hydrogen bonds, while a combination of C—H...O and C—H...π(arene) hydrogen bonds links the molecules of 3‐tert‐butyl‐1‐phenyl‐7‐(3,4,5‐trimethoxybenzyl)‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine, C₂₅H₃₁N₃O₄, (VIII), into complex sheets. In each compound, the oxazine ring adopts a half‐chair conformation, while the orientations of the pendent phenyl and tert‐butyl substituents relative to the pyrazolo[3,4‐d]oxazine unit are all very similar.     

Conformational Analysis and Selection of Odor‐Active Conformers: Synthesis of Molecules Designed for the Lily‐of‐the‐Valley(Muguet)‐Type Odor

The selection of odor‐active conformers and the construction of a model for a targeted odor type, i.e., for the lily‐of‐the‐valley odor, were examined. The disagreement of the odors of 1,3,4,5‐tetrahydro‐2‐benzoxepin derivative 1 and 3‐[4‐(tert‐butyl)phenyl]‐2‐methylpropanal ( 2 ) is discussed in terms of their stable conformers. The conformer active for the lily‐of‐the‐valley odor was investigated by conformational analyses of several related compounds. Based on the integrated model consisting of the assumed active conformers (Fig. 5), compounds anticipated to possess the lily‐of‐the‐valley odor were designed and synthesized. The odor of synthetic 7‐(tert‐butyl)‐1,2,4,5‐tetrahydro‐3H‐benzocyclohepten‐3‐one ( 8 ) and 3‐[4‐(tert‐butyl)phenyl]cyclopentanone ( 13 ) were evaluated by perfumers to have a floral odor and to recall the lily‐of‐the‐valley and lilac odors, respectively. Our methodology to design new odoriferous compounds, based on conformational analysis, selection of odor‐active conformers, and construction of a model, proved to be satisfactory.     

One‐pot Method for Reduction of Pyrazolo[5,1‐c][1,2,4]Triazine‐7‐diazonium Tetrafluoroborate to 7‐Hydrazinyl Derivatives

New convenient one‐pot method for reduction of hetarenediazonim tetrafluoroborates to the hetarylhydrazine derivatives was developed. Interaction of 8‐carboxyethyl‐3‐(tert‐butyl)‐4‐oxo‐4,6‐dihydropyrazolo[5,1‐c ][1,2,4]triazine‐7‐diazonium tetrafluoroborate with anhydrous SnCl₂ in anhydrous CF₃CO₂H, and further sequence of one‐pot operations led to formation of various derivatives of the unstable ethyl 3‐(tert‐butyl)‐7‐hydrazinyl‐4‐oxo‐4,6‐dihydropyrazolo[5,1‐c ][1,2,4]triazine‐8‐carboxylate (hydrochloride, hydrazides, hydrazones, and pyrazoles), which were isolated in high yields. The anhydrous conditions were first used with SnCl₂ and allowed to exclude hydrolysis of the ester group and formation of the by‐products.     

Synthesis and biological activity of novel N‐tert‐butyl‐N,N′‐substitutedbenzoylhydrazines containing 2‐methyl‐3‐(triphenylgermanyl)propoxycarbonyl

In a search for new insect growth regulators with unusual biological properties and different activity spectrum, we thought that the preservation of the bioactive unit and the introduction of 2‐methyl‐3‐(triphenylgermanyl)propoxycarbonyl in N‐tert‐butyl‐N,N′‐dibenzoylhydrazine would enhance their larvicidal activities to a significant degree. Therefore, we designed and synthesized N′‐tert‐butyl‐N′‐[2‐methyl‐3‐(triphenylgermanyl)propoxycarbonyl]‐N‐benzoylhydrazine and analogs by two procedures. These novel compounds were characterized by elemental analyses, IR, and ¹H NMR. At the same time, N‐tert‐butyl‐N‐substitutedbenzoylhydrazines were prepared by a new method, and some reactions involved were studied. The preliminary results indicate that some compounds have inhibitory effects against plant pathogenetic bacteria such as early blight of tomato. Copyright © 2002 John Wiley & Sons, Ltd.     

Comment on the paper “Extensive Theoretical Studies of a New Energetic Material: Tetrazino‐Tetrazine‐Tetraoxide (TTTO)” by Xinli Song,Jicun Li,Hua Hou,and Baoshan Wang

Discrepancies are noted in the implementation and presentation of the ccCA methodology in a previous publication, “Extensive Theoretical Studies of a New Energetic Material: Tetrazino‐tetrazine‐tetraoxide (TTTO)” by Xinli Song, Jicun Li, Hua Hou, and Baoshan Wang. The enthalpy of formation for TTTO has been re‐evaluated using the correct implementation of the ccCA methodology, demonstrating the results to be comparable to those of other ab initio composite methods. © 2012 Wiley Periodicals, Inc.