Integrastatins are naturally occurring heterotetracyclic compounds with a broad spectrum of biological activity. A number of new structural analogues of integrastatins 2a-u have been synthesized using a novel one-step method [1], but a systematic theoretical study of their structural features and biological activity has not been realized. This study aimed to in silico investigate physicochemical and bioactivity properties for a series of 21 new synthetic analogues of natural integrastatins. Global chemical reactivity descriptors was assessed using DFT B3LYP 6-311++G(d, p) CPCM (solvent — water) calculations. High ionization potential IP in the range from 5.9 to 7.1 eV and electron affinity EA at the level of 2.1 to 3.2 eV were shown, which together with a sufficiently large energy gap DEgap from 3.8 to 4.6 eV indicates the hard nature of the compounds 2a-u. Antiviral activity and inhibitory potential as CYP2C19 inducers were identified using the PASSOnline resource. According to the results of molecular docking studies Human immunodeficiency virus HIV-1 reverse transcriptase protein (PDB ID: 3V81) and protein of the RNA-dependent RNA polymerase of the SARS-CoV-2 (PDB ID: 7AAP) can serve as a likely biological target for the compounds 2a-u. Potentially high oral efficacy and a promising safety profile for the therapeutic use were showed using ADMETlab 3.0 online portal. Further experimental in vitro and in vivo studies of the pharmaceutical potential of compounds 2a-u is need for more accurate evaluation the assumptions made on the basis of in silico approach.

Herein, we report an unexpected pseudo-multicomponent transformation discovered during attempts to selectively nitrate the pyridine core of 3-acetyl-2,4,6-trimethylpyridine (3). Despite employing standard nitration conditions, including KNO₃–H₂SO₄ and HNO₃–H₂SO₄ mixtures, electrophilic substitution of the aromatic ring did not occur. Instead, the reaction sequence promoted an in situ nitrozation, dehydration to nitrile oxide intermediates, and subsequent [3+2]-cycloaddition involving two substrate molecules. This process yielded a novel, highly functionalized furoxan derivative, precisely identified as 3,4-bis(2,4,6-trimethylnicotinoyl)-1,2,5-oxadiazole 2-oxide (5). The molecular architecture of compound 5 was established by ¹H and ¹³C NMR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction (XRD) analysis. To elucidate the stereochemical and electronic features governing compound 5, DFT calculations were performed at the ωB97X-D/6-311++G(d,p) level of theory. The experimental crystallographic disorder of the N-oxide oxygen atom was computationally rationalized by the thermodynamic near-degeneracy (ΔG < 0.63 kcal/mol) of two orientational isomers (5a and 5b). Furthermore, frontier molecular orbital analysis within the framework of perturbation theory accounted for the head-to-tail regioselectivity during cyclization, while wide energy gaps (ΔE = 8.13–8.27 eV) and high chemical hardness (η = 4.07–4.14 eV) underscored the kinetic stability of the heterocycle. Phenotypic and target-specific in silico profiling using PASS Online identified Matrix Metalloproteinase-9 (MMP-9) as a relevant target for potential hemorheological and cardioprotective applications. Validated molecular docking simulations across three human MMP-9 crystallographic domains (PDB: 8K5Y, 6ESM, 4XCT) demonstrated competitive binding affinities and balanced Ligand Efficiency metrics (LE = 0.26–0.29 kcal/mol/heavy atom), anchoring compound 5 within the catalytic pocket via conventional hydrogen bonds and π-mediated interactions. Finally, in vitro evaluations using a blood hyperviscosity model confirmed significant hemorheological efficacy, as compound 5 effectively prevented the rise in blood viscosity, outperforming the reference drug pentoxifylline. The convergence of computational insights and experimental functional activity establishes this novel bis(nicotinoyl)furoxan framework as a promising candidate for further hemorheological and cardioprotective applications.