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Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
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Computational Design and Theoretical Evaluation of Novel Heterocyclic Energetic Materials Based on

Luciana Amorim da Silva1, Nathália Magalhães Paixão Rosa2, Danillo Fernando Vianna Cantini3

  • 1Chemical Engineering Department, Military Institute of Engineering, Rio de Janeiro, Rio de Janeiro, Brazil.

Journal of Computational Chemistry
|September 4, 2026
PubMed

Keywords:
DFTaromaticybond order analysisdetonation propertiesenergetic materialsnitrogen heterocyclessubstituent effects

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Five-Membered Heterocyclic Aromatic Compounds: Overview

Heterocyclic aromatic compounds are cyclic compounds that are aromatic and have one or more heteroatoms—atoms other than carbon, in the ring. Depending upon the number of atoms present in the ring, they can be either five or six-membered. Examples of five-membered heterocyclic aromatic compounds include pyrrole, furan, thiophene, and imidazole. Pyrrole consists of one nitrogen atom having one lone pair of electrons. Furan and thiophene have one oxygen and one sulfur heteroatom, respectively.
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Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
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Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
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