Appeal No. 1996-0709
Application No. 08/228,245
specification:
Considerable effort in recent years has been
directed toward the synthesis of polynitrocubanes
because of the potential use of this class of
energetic materials as explosives, propellants,
fuels and binders (Chemistry of Energetic Materials;
Ed., G.A. Olah; D.R. Squire; Academic Press, Inc.,
San Diego, CA, 1991. Also see Carbocyclic Cage
Compounds; Ed., E.J. Osawa; O. Yonemitsu; VCH
Publishers, Inc., New York, NY, 1992). The compact
structures of cage molecules result in high
densities, and the introduction of NO groups further
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enhances the density. The strain energy present in
the cubane skeleton (>166 kcal/mol) is an added
bonus to its performance. Furthermore, preliminary
results with polynitrocubanes indicate that such
compounds are thermally very stable and are also
very insensitive energetic materals. Consequently,
it is of interest to introduce functional groups on
the cubane skeleton which can be converted to nitro
group or other active functionalities.
Direct functionalization of nitrocubanes, while
an attractive approach, has not heretofore been
realized. Cationic or anionic reactions, due to the
activity of the nitro groups give either decomposed
products or recovered starting materials. We report
here an efficient direct functionalization of a
nitrocubane molecule by its irradiation in a
solution of oxalyl halide (for a related case see
Wiberg, K.B.; 10 Annual Working Group Meeting, Juneth
3-6, 1992, Kiamesha Lake, NY. For much simpler
cases see Wiberg, K.B.; Williams, Jr., V.Z.; J. Org.
Chem., 1970, 35 369; Applequist, D.E.; Saski, T.; J.
Org. Chem.; 1978, 43, 2399). This new and
potentially powerful synthetic development will
greatly shorten the number of steps necessary to
obtain nitrocubane derivatives which are otherwise
difficult to synthesize.
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