Search

A preparatively convenient one-pot method for the synthesis of new 7-thioxo[1,3]thiazolo[3,2-c]pyrimidine derivatives 3a���3l by the cyclocondensation of 5-methyl(1,3-thiazolidin-2-ylidene)ketones 1a���1c with aroyl 2a���2d and 2-thienyl 2e isothiocyanates for 6���10 h boiling in acetone has been developed. Studies of the antimicrobial and antioxidant activities potential of the obtained compounds revealed that [2-methyl-5-(4-nitrophenyl)-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidine-8-yl](phenyl)methanone 3k, effect on the test culture of M. luteum at a concentration of 0.5% is close to the control drug vancomycin. Moreover, [5-(4-bromophenyl)-2-methyl-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidin-8-yl](phenyl)methanone 3j has an antibacterial effect on the specified test culture at a minimum inhibitory concentration of 15.6 ��g/mL. In turn, 1-(2-methyl-5-(thiophen-2-yl)-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidin-8-yl]ethanone 3d can be considered promising for further structural modification to enhance the antioxidant effect. The structure of all synthesized substances was established by spectral analysis (1H and 13C NMR, LC���MS, and FT-IR). Additionally, the structure of compound 3i was confirmed by X-ray diffraction analysis.

A pentanuclear CuII5-hydroxo cluster possessing an unusual linear-shaped configuration was formed and crystallized under hydrothermal conditions as a result of the unique cooperation of bridging 1,2,4-triazole ligand (trans-1,4-cyclohexanediyl-4,4′-bi(1,2,4-triazole) (tr2cy)), MoVI-oxide, and CuSO4. This structural motif can be rationalized by assuming in situ generation of {Cu2Mo6O22}4– anions, which represent heteroleptic derivatives of γ-type [Mo8O26]4– further interlinked by [Cu3(OH)2]4+ cations through [N−N] bridges. The framework structure of the resulting compound [Cu5(OH)2(tr2cy)2Mo6O22]·6H2O (1) is thus built up from neutral heterometallic {Cu5(OH)2Mo6O22}n layers pillared with tetradentate tr2cy. Quantum-chemical calculations demonstrate that the exclusive site of the parent γ-[Mo8O26]4– cluster into which CuII inserts corresponds with the site that has the lowest defect (“MoO2 vacancy”) formation energy, demonstrating how the local metal-polyoxomolybdate chemistry can express itself in the final crystal structure. Magnetic susceptibility measurements of 1 show strong antiferromagnetic coupling within the Cu5 chain with exchange parameters J1 = −500(40) K (−348(28) cm–1), J2 = −350(10) K (−243(7) cm–1) and g = 2.32(2), χ2 = 6.5 × 10–4. Periodic quantum-chemical calculations reproduce the antiferromagnetic character of 1 and connect it with an effective ligand-mediated spin coupling mechanism that comes about from the favorable structural arrangement between the Cu centers and the OH–, O2–, and tr2cy bridging ligands.