Synthesis and characterization of 2,5-dibutylthio-2,3-dihydro-2-formyl-4H-pyran thiosemicarbazones and their copper complexes

Previously unknown derivatives of thiosemicarbazide were obtained in high yields by the condensation reaction of 2,5-dibutylthio-2,3-dihydro-2-formyl-4H-pyran with 4-phenylthiosemicarbazide or thiosemicarbazide when boiling in EtOH. The reaction products are represented by colored oils. Cu(II) complexes based on 2,5-dibutylthio-2,3-dihydro-2-formyl-4H-pyran carbazones were synthesized by their interaction with copper (II) chloride. All these complexes are soluble in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) and, according to elemental analysis, have a 1:1 metal-ligand stoichiometry. The obtained compounds were studied using IR and 1H, 13C, 15N NMR spectroscopy, as well as elemental analysis. The obtained copper-containing complexes with thiosemicarbazones are of particular interest due to their pronounced biological activity. The thiosemicarbazone 2,5-dibutylthio-2,3-dihydro-2-formyl-4H-pyran compound was subjected to primary screening for acute toxicity. The obtained results showed that, when taken intragastricaly, the studied compound can be characterized as a substance with a low risk of acute toxicity. According to the DL50 parameter, the compound belongs to the V hazard class (DL50>2000 mg/kg).