Kurt Baum

Preparation of 1,2-dibromodinitroethylene and 1,1-dibromodinitroethylene

Abstract 1,2-Dibromodinitroethylene and 1,1-dibromodinitroethylene were obtained by the thermolysis of 1,1,2-tribromotrinitroethane. 1,2-Dibromodinitroethylene reacted with methanol to give methyl bromonitroacetate,and gave a Diels-Alder adduct with cyclopentadiene. 1,1-Dibromodinitroethylene reacted with ethylenediamine to give 2-(dinitromethylene)-1,3-diazacyclopentane, obtained previously from 1,1-diiododinitroethylene.

The structural chemistry of energetic compounds containing geminal-difluoramino groups

Abstract This report discusses the structural chemistry of four molecules containing geminal-difluoramine (NF2) groups. They are: 1,1,4,4-tetrakis(difluoramino)cyclohexane (1), monoclinic, P21/n, a=6.277(1), b=10.502(2), c=7.910(1) A, β=99.50(1)°; 1-{3-[5,5-bis(difluoramino)-2-oxopyrrolidinyl]-2-oxopropyl}pyrrolidine-2,5-dione (2), monoclinic, P21/c, a=12.994(1), b=8.4799(8), c=13.142(1) A, β=102.998(7)°; 1-[2,2-bis(difluoramino)propyl]-pyrrolidine-2,5-dione (3), monoclinic, P21, a=6.488(1), b=9.508(2), c=8.612(1) A, β=105.52(1)°; and 2-[2,2-bis(difluoramino)propyl]isoindoline-1,3-dione (4), orthorhombic, Pbca, a=15.718(1), b=7.0818(5), c=22.039(2) A. The pyramidal difluoramine group sometimes displays extensive torsional disorder in crystals, but in each of the structures reported here, the geminal-NF2 groups are primarily ordered, due to interactions with their steric environments. There are increases in the thermal parameters of the fluorine atoms indicating libration in some cases, where there are fewer steric demands in the NF2 environment. The conformation adopted by each NF2 group can be explained in terms of minimization of non-bonded F⋯H and F⋯F contacts. All NF2 groups are nonplanar and show unusual metrical parameters compared to amines containing no fluoro substituents. The interior FNF and CNF angles are very small, indicating a high degree of pyramidalization. This type of behavior has been attributed to pπ–s resonance and electrostatic effects.

Reaction of 1,1-diiododinitroethylene with fluoride. Preparation of 1,1,1-trifluorodinitroethane derivatives.

Abstract The reaction of 1,1-diiododinitroethylene with tetrabutylammonium fluoride gave the tetrabutylammonium salt of 1,1,1-trifluorodinitroethane. Acidification of this salt in ethyl acetate, extraction of tetrabutylammonium salts with water, and addition of sodium bicarbonate led to the isolation of the sodium salt of 1,1,1-trifluorodinitroethane. The reaction of formaldehyde with the tetrabutylamminium salt gave 3,3,3-trifluoro-2,2-dinitropropanol, which was converted to its formal with trioxane and sulfuric acid.

Synthesis of bis(3,3-dinitrobutyl)polysiloxanes

Abstract Phenyl groups were used as silicon-protecting groups in the synthesis of bis-(3,3-dinitrobutyl)polysiloxanes. The addition of diphenylsilane to acrolein dimethyl acetal, followed by reactions with methyllithium and phosphorus tribromide gave bis(3-bromobutyl)diphenylsilane. Sodium nitrite displacement gave bis(3-nitrobutyl)diphenylsilane, and oxidative nitration gave bis(3,3-dinitrobutyl)diphenylsilane. Dephenylation with bromine and hydrolysis gave cyclic polysiloxanes.