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1,2,5,6-azobicyclo octene

An alternative name could be pyrrolo[2,1-c]-1,2,3-triazole (PT).
 
1
the aromatic nature of the double ring system would lend stability. Three nitro groups instead of two (with only one amino) would probably not be unstable either, since the tetrazene center could act as an electron donor to an electron-withdrawing nitro group.
This could be an energetic compound with both excellent explosive performance and good resistance to impact.
 
1
obviously there would be a significant danger of explosion trying to convert the tetrazo-cyclooctene into bicyclo-tetrazo-cyclooctene, but there is no obvious alternative route. (see the attachment at the bottom of the page, the oxidation step shown would not be ideal, since the bromo,chloro-ethyl group would be more vulnerable to attack than the methyl groups, if you can think of a good idea to modify the procedure you are welcome to email me)
 
Tetrazo-cyclooctene would be more accurately refered to as 1,2,5,6-tetrazocyclooctatetraene
 
As a side note, the octagonal aromatic ring C8H8 is known as cyclooctatetraene. Melting point: -27degC. Boiling point: 142-143degC Extremely flammable. It should be noted that, although the compound is conjugated, it is not considered aromatic, since the molecular shape is not planar. C8H8 can, however, form a salt with potassium, the resulting C8H8(-2) anion is both planar and aromatic. The complex Fe(C8H8)2 was refluxed in a mixture of toluene, dimethyl sulfoxide,and dimethoxyethane for 5 days, forming magnetite and crystalline carbon that also contained carbon nanotubes! "Crystalline Graphite from an Organometallic Solution-Phase Reaction" Erich C. Walter, Tobias Beetz, Matthew Y. Sfeir, Louis E. Brus, and Michael L. Steigerwald J. Am. Chem. Soc. 128(49) p15590 - 15591 (year 2006)
 
Both cylcooctenes would be highly poisonous, volatile, and dangerously sensitive to detonation, especially if any open flame is present. (although hydrazine cannot be detonated, both azomethane and tetramethyl hydrazine are fairly sensitive explosive compounds due to lack of intermolecular hydrogen bonding) The heating should be done outside using an electric hotplate, wearing a protective personal respirator.
 
Addition of even one amino group to the double ringed molecule would greatly reduce the sensitivity.
 
A note about attempting a synthesis, glyoxal is known to irreversibly transform into glycolic acid under alkaline conditions. It is not known how this could affect the proposed condensation. Possibly a different route would need to be used to form the C4N4 octagonal aromatic ring. This ring might not be stable in the presence of water, since hydrazine is somewhat basic.
 

This type of synthetic route proposed has previously been successful in producing adjoining pentagonal rings containing four connected nitrogen atoms, although in a slightly different arrangement. Thermal cylization of              1-azido,2-(1N-connected-1,2,3-triazole) benzene resulted in loss of N2 and bonding of the nitrogen atom from the former azido group to the 2-position on the triazole ring. This had a triple ringed structure, containing two adjoining pentagonal rings, but with one of the central nitrogen atoms connected to three other nitrogen atoms.

R.A. Carboni, J.C. Kauer,  J. American Chem. Society, volume 89, p2633, (1967).

 

(H4C6)--(N3C2H2)

…….(….//

………N

 

 

See the second attachment at the bottom of the page for a different theoretic route for the pyrrolo-triazole.

 
 
 
3,6-Dinitropyrazolo[4,3-c]pyrazole (DNPP)
 
A different isomer based on the C4H4N4 double ring is also known to exist.
 
 
3-carboxy-6-nitro- pyrazol[4,3-c]pyrazole was treated with 98% HNO3 at 45degC to give DNPP in 70% yield. The net yield of the DNPP, starting from the original acetylacetone before the first step, was 21%,  The physical and safety properties of DNPP were measured. DNPP exothermically decomposes at elevated temperatures; the decomposition rate peaks at 330degC.
 
Sensitivity
The sensitivity of DNPP was measured using a 5kg hammer. The drop height at which the probability of detonation approached 50% was measured at 68cm. (compare to a value of 32 cm for HMX). Basic testing did not reveal any sensitivity to friction or sparks. The compound shows good thermal stability.
 
Explosive Performance
DNPP has a density of 1.865 g/cm3. The heat of formation was measured at +65 kcal/mol. DNPP is predicted to have 85% of the power of HMX.
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005.bmp
(360k)
Anders Hoveland,
Jul 31, 2011, 8:31 PM
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0056.bmp
(1216k)
Anders Hoveland,
Aug 5, 2011, 3:33 AM
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0062.bmp
(207k)
Anders Hoveland,
Aug 11, 2011, 12:52 PM
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Anders Hoveland,
Jan 18, 2011, 1:14 PM
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Anders Hoveland,
Feb 7, 2011, 12:56 PM
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