Synthesis of Novel Hexaazaisowurtzitane Cages to Access CL‐20

Kommu, Nagarjuna; Aravindu, Pampuram; Rani, Karike Durga; shaik, Adul Munaf; Rao, Venkat K.

doi:10.1002/ajoc.202100680

Cited by 7 publications

(1 citation statement)

References 42 publications

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“…Hexaazaisowurtzitane derivatives can only be obtained in acceptable yields by the condensation of glyoxal with benzylamine (its derivatives), benzylamine-like compounds (a series of amines bearing an aromatic moiety linked via a methylene bridge to the amino group), allylamine (or similar compounds) and, as it turned out most recently, with a primary amine where the amino group is linked to the strained aliphatic ring such as cyclopropylamine and cyclobutylamine [15,23,98,99].…”

Section: Introductionmentioning

confidence: 99%

Condensation of Benzyl Carbamate with Glyoxal in Polar Protic and Aprotic Solvents

Paromov

2023

Molecules

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The synthesis of substituted 2,4,6,8,10,12-hexaazaisowurtzitane via direct condensation is challenging. The selection of starting ammonia derivatives is very limited. The important step in developing alternative synthetic routes to these compounds is to investigate their formation process in detail. Here, we examined an acid-catalyzed condensation between benzyl carbamate and glyoxal in a ratio of 2:1 in a range of polar protic and aprotic solvents, and discovered a new process occurring during the cascade condensation of glyoxal with ammonia derivatives as well as discovered several processes hindering the formation of caged compounds. More specifically, a cyclic compound, N,N′-bis(carbobenzoxy)-3,6-diamino-1,4-dioxane-2,5-diol, was found to form at the early stage of condensation under low acidity conditions. The formation of this compound is governed by an easier condensation of alcohol groups compared to the amide ones. The condensation intermediates, N,N′-bis(carbobenzoxy)ethan-1,2-diol, N,N′,N″-tris(carbobenzoxy)ethanol, and N,N′,N″,N‴-tetrakis(carbobenzoxy)ethan, were obtained at a higher acidity. A range of solvents were identified: those that react with benzyl carbamate, those that promote the progress of side processes, and those that promote precipitation of condensation intermediates. A few byproducts were isolated and identified. It was found that DMSO exhibits a strong deactivating ability, while CH3CN exhibits a strong activating ability towards the acid-catalyzed condensation process of benzyl carbamate with glyoxal.

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Section: Introductionmentioning

confidence: 99%

Condensation of Benzyl Carbamate with Glyoxal in Polar Protic and Aprotic Solvents

Paromov

2023

Molecules

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Rediscovering N‐Methyltetranitropyrrole – A Versatile High Energy MaterialviaFacile Two‐step Eco‐friendly Synthetic Approach

et al. 2022

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A highly efficient 2-step method, where three nitro groups could be directly introduced upon pyrrole moiety in a single step, was developed as an environmentally benign process for the synthesis of N-methyltetranitropyrrole (1) employing metal nitrate/conc. sulphuric acid as the nitrating reagent. This method resulted 1 in high purity having higher thermal stability (273 °C) along with reduced sensitivity (impact sensitivity > 40 J; fricition sensitivity > 360 N), which makes it a versatile high energy material. An over-oxidized new product 1-methyl-3,3,4,4-tetranitropyrrolidine-2,5-dione (4) was also isolated during optimization, whose energetic properties are similar to those of RDX.

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Development of Green Energetic Oxidizers for Solid Propellant Applications: Present Status

Arun Kumar,

Purayil Dhanya,

Venugopal

et al. 2024

Propellants Explo Pyrotec

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The quest for new high‐energy materials (HEMs) with superior performance properties compared to conventional HEMs has opened up a new area of research and has resulted in the synthesis of many novel molecules. The challenge is to balance superior performance with stability while adopting an environmentally benign approach during synthesis, use, and disposal. This multipoint challenge has united theoretical, experimental, and applied researchers toward achieving this goal. Oxidizers are HEMs that possess stoichiometric excess of oxygen, which is used to oxidize the binder‐fuel and solid fuel additives in solid propellants. Ammonium perchlorate (AP), a commonly used oxidizer in solid propellants, needs replacement due to environmental and performance concerns. The demand for new “green energetic oxidizers” has led to the synthesis of dinitramide and trinitromethane salts, polynitroazoles, and strained‐ring compounds. Some of these compounds can be effectively used as energetic fillers to improve the overall performance of the solid propellants. This review assesses AP and ammonium nitrate in propellant applications and the performance challenges associated with the use of ammonium dinitramide (ADN), hydrazinium nitroformate, trinitroazetidine, and hexanitrohexaazaisowurtzitane (CL‐20) in propellant formulations. The synthetic feasibility of these new oxidizers, their decomposition behaviour, performance, compatibility in propellant formulations, and ways to overcome these difficulties are discussed. Evaluation of the theoretical performance of these molecules indicated that the ADN − Glycidyl azide polymer is a promising combination. However, ADN is highly hygroscopic, and an anti‐hygroscopic strategy needs to be developed. Finally, this review examines the possible identification of practical oxidizers for application purposes.

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Synthesis of Novel Hexaazaisowurtzitane Cages to Access CL‐20

Cited by 7 publications

References 42 publications

Condensation of Benzyl Carbamate with Glyoxal in Polar Protic and Aprotic Solvents

Condensation of Benzyl Carbamate with Glyoxal in Polar Protic and Aprotic Solvents

Rediscovering N‐Methyltetranitropyrrole – A Versatile High Energy MaterialviaFacile Two‐step Eco‐friendly Synthetic Approach

Development of Green Energetic Oxidizers for Solid Propellant Applications: Present Status

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