Formylphenyloxohydroepoxyisoindole carboxylates were prepared by the reaction of 4-hydroxy-3-methoxy-, 4-hydroxy-3-ethoxy- and 3-hydroxy-4-methoxybenzaldehydes with substituted isoindolecarboxylic acids {2-methyl-1-oxo-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole-7-carboxylic, 2-(3,4-dimethoxyphenethyl)1-oxo-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole-7-carboxylic, 2-(benzo[d][1,3]dioxol-5-ylmethyl)-1-oxo1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole-7-carboxylic, 6-oxo-3,4,6,6a,7,8-hexahydro-2H,10bH-8,10a-epoxy[1,3]oxazino[2,3-a]isoindole-7-carboxylic, 2-(2,3-dichlorobenzyl)-1-oxo-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole-7-carboxylic} in dichloromethane in the presence of dicyclohexylcarbodiimide. The corresponding (E)-azomethines were synthesized by condensation of formylphenyloxohydroepoxyisoindole carboxylates with 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one in methanol.

The title molecule, C₁₆H₁₀BrNO₂, is essentially planar (r.m.s. deviation = 0.004 Å). In the crystal, molecules are linked by C—H...O and C—H...Br hydrogen bonds, forming ribbons along the b-axis direction. Furthermore, π-π interactions cause the molecules to form ribbons along the [1 0 \overline{10}] and [1 0 10] directions [centroid-to-centroid distances = 3.703 (3), 3.734 (3), 3.703 (3), and 3.734 (3) Å]. According to a Hirshfeld surface analysis, H...H (33.8%), O...H/H...O (15.1%), C...H/H...C (14.6%), Br...H/H...Br (13.8%), and C...C (11.9%) interactions are the main contributors to the crystal packing.

Arylmethylenebis(3-hydroxy-2-cyclohexen-1-ones) were obtained by condensation of 1,2-azole- and pyridine-substituted aromatic aldehydes of the vanillin series with 1,3-cyclohexanedione in methanol in the presence of trimethylamine. Catalytic cyclization using fibrous sulfocationite FIBAN K-1 gave corresponding 1,8-dioxooctahydroxanthenes.

The antiviral activity of 12 nitrogenand oxygen-containing heterocyclic compounds was studied by screening against the vaccinia virus in Vero cell culture and the data obtained were compared with the results of ab initio quantum chemical calculations using the DFT (density functional theory) method. The index of selectivity was found to be contingent upon the toxicity of the compounds under study. Compounds containing a 2,3-dichlorobenzyl group were found to be more toxic and unpromising as antiviral compounds. In addition, biological testing showed that (E)-azomethines containing a fragment of 1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole showed no antiviral activity. Compounds derived from vanillin and vanillal have proved to be the most promising in relation to the smallpox vaccine virus. The method of preliminary quantum chemical modeling can make it possible to identify unpromising, low-activity structures even at the planning stage of work on the synthesis and bioscreening of new chemical compounds.

In the crystal structure of the title compound, C ₁₉ H ₁₇ NO ₃ , C—H...O hydrogen bonds connect molecular pairs to produce dimers with an R ² ₂ (16) ring motif. Additionally, C—H...π interactions form ribbons along the [101] direction. Van der Waals interactions between the ribbons help to consolidate the molecular packing. Hirshfeld surface analysis shows that H...H (45.5%), C...H/H...C (30.4%), and O...H/H...O (19.3%) interactions are the main contributors to the crystal packing.

By the condensation of 1-oxo-1,2,3,6,7,7a-hexahydrohydro3a,6-epoxyisoindole-7-carboxylic acids with 4-aminoantipyrine or N-methyl-1-[5-(p-tolyl)isodiesol-3-yl]methylamine in the presence of dicyclohexylbisodiimidine in a dichloromethane medium, corresponding amides with a yield of 67–78 % were synthesized. By the interaction of 1-oxo-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoisoindole-7-carboxylic acids with 4-aminoantipyrine or N-methyl-1-[5-(p-tolyl)isodioxol-3-yl]methylamine in methanol, corresponding ammonic salts with a yield of 93–97 % were obtained. Quantumchemical modelling of energy parameters and electronic structure of synthesized compounds by ab initio method, with the level of theory B3LYP1/MIDI, was carried out in order to preliminary assess their potential antibacterial and antiviral properties. The antimicrobial activity of the synthesized compounds against the strains Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 11229 was studied.