The direct electrophilic α-cyanation of β-keto esters and amides has been developed using a hypervalent iodine benziodoxole-derived cyano reagent. The procedure is accomplished within 10 min and without the use of any catalyst in DMF, at room temperature. Thus, the highly functionalized quaternary carbon-centered nitriles were produced in high to excellent yields.
The investigation of high-nitrogen compounds has been
significant
for the evolution of energetic materials. Azo-bis-1,2,4-triazole (aTRz)
can be an excellent energetic backbone, owing to its characteristics:
high heat of formation, high nitrogen content, and plane structure.
Nevertheless, aTRz-based energetic compounds have been rarely synthesized
using the covalent modification method, owning to the decomposition
of aTRz under harsh reaction conditions. Cocrystallization has been
widely used as a mild and efficient method for modulating the properties
of energetic compounds. In this study, electrostatic potential (ESP)
maps were used for theoretical guidance, and four aTRz-based energetic
cocrystals have been obtained via cocrystallization. The single-crystal
structures of these cocrystals indicated that the N···H–N
hydrogen bonds between the side nitrogen atoms of aTRz and the amino
groups of the nitro azole compounds were the driving force for the
assembly of multimers with aTRz and polynitroazole compounds. Consequently,
the formation of cocrystals via the self-assembly of these multimers
was driven by other weak hydrogen bonds and van der Waals forces.
The detonation performance of aTRz-based cocrystals was increased
by appropriately selecting the coformers. Particularly, when 4-amino-3,5-dinitro-pyrazole
(ADNP) was used as coformer, resultant cocrystal 3 was
a potential high-energy density material that exhibited high density,
high detonation velocity (8329 m s–1) and detonation
pressure (28.6 GPa). Thus, in this study, cocrystallization has been
demonstrated to be an effective method for the noncovalent modification
of aTRz-based energetic materials.
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