Application of the intramolecular Diels-Alder vinylarene (IMDAV) reaction for the synthesis of benzo-, carbocyclo-, thienothiopheneisoindolecarboxylic acids and its limitations.

Thienylallylamines, readily accessible from the corresponding thienyl aldehydes, react with maleic and trifluoromethylmaleic anhydrides leading to the formation of acids with a thieno[2,3-f]isoindole core. The reaction sequence involves two successive steps: acylation of the nitrogen atom of the initial allylamine and the intramolecular Diels-Alder vinylarene (IMDAV) reaction. The scope and limitations of the proposed method were thoroughly investigated. It has been revealed with the aid of X-ray analysis and DFT calculations that the key step, the IMDAV reaction, proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. The obtained functionally substituted thieno[2,3-f]isoindole carboxylic acids are potentially useful substrates for further transformations and bioscreening. The antimicrobial evaluation of the obtained compounds revealed that 1-oxo-2-(3-(trifluoromethyl)phenyl)hexahydrobenzo[4,5]thieno[2,3-f]isoindole-10-carboxylic acid is the most active sample in the synthesized library. It exhibits antibacterial activity against sensitive strains of Gram-positive bacteria, including S. aureus, Enterococcus faecium, Bacillus cereus, and Micrococcus luteus, as well as the Gram-negative bacteria E. coli and Pseudomonas fluorescens, with MIC values ranging from 4 to 64 µg mL-1. 9-Oxo-8-phenyloctahydronaphtho[2,1-d]thieno[2,3-f]isoindole-10-carboxylic acid showed antifungal activity against yeast culture C. albicans with a MIC value of 32 µM.

Crystal structure and Hirshfeld surface analysis of 3-benzyl-2-[bis(1H-pyrrol-2-yl)methyl]thiophene.

In the title compound, C20H18N2S, the asymmetric unit comprises two similar mol-ecules (A and B). In mol-ecule A, the central thio-phene ring makes dihedral angles of 89.96 (12) and 57.39 (13)° with the 1H-pyrrole rings, which are bent at 83.22 (14)° relative to each other, and makes an angle of 85.98 (11)° with the phenyl ring. In mol-ecule B, the corresponding dihedral angles are 89.49 (13), 54.64 (12)°, 83.62 (14)° and 85.67 (11)°, respectively. In the crystal, mol-ecular pairs are bonded to each other by N-H⋯N inter-actions. N-H⋯π and C-H⋯π inter-actions further connect the mol-ecules, forming a three-dimensional network. A Hirshfeld surface analysis indicates that H⋯H (57.1% for mol-ecule A; 57.3% for mol-ecule B), C⋯H/H⋯C (30.7% for mol-ecules A and B) and S⋯H/H⋯S (6.2% for mol-ecule A; 6.4% for mol-ecule B) inter-actions are the most important contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of (Z)-4-({[2-(benzo[b]thio-phen-3-yl)cyclo-pent-1-en-1-yl]meth-yl}(phen-yl)amino)-4-oxobut-2-enoic acid.

In the title compound, C24H21NO3S, the cyclopentene ring adopts an envelope conformation. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming ribbons along the a axis. Inter-molecular C-H⋯O hydrogen bonds connect these ribbons to each other, forming layers parallel to the (01) plane. The mol-ecular packing is strengthened by van der Waals inter-actions between the layers. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 46.0%, C⋯H/H⋯C 21.1%, O⋯H/H⋯O 20.6% and S⋯H/H⋯S 9.0%.

Crystal structure and Hirshfeld surface analysis of 4,5-di-bromo-6-methyl-2-phenyl-2,3,3a,4,5,6,7,7a-octa-hydro-3a,6-ep-oxy-1H-isoindol-1-one.

In the title compound, C15H15Br2NO2, two bridged tetra-hydro-furan rings adopt envelope conformations with the O atom as the flap. The pyrrolidine ring also adopts an envelope conformation with the spiro C atom as the flap. In the crystal, the mol-ecules are linked into dimers by pairs of C-H⋯O hydrogen bonds, thus generating R 2 2(18) rings. The crystal packing is dominated by H⋯H, Br⋯H, H⋯π and Br⋯π inter-actions. One of the Br atoms is disordered over two sites with occupation ratio of 0.833 (8):0.167 (8).