A series of new 4-(1,3,4-thiadiazol-2-yl)-containing polysubstituted pyrroles 3 a-k has been synthesized by a preparative convenient method from ethyl 5-chloro-4-formyl-1H-pyrrole-3-carboxylates 1 a-e, which were selectively transformed into the corresponding polysubstituted pyrrole-4-carboxylic acids 2 а-е using sodium hypochlorite as an oxidizer. Further, they were transformed into the target compounds with a high yield using the cyclocondensation with N-mono- or N,N-disubstituted thiosemicarbazides in the boiling phosphorus trichloroxide. As seen from the screening of antimicrobial activity, the synthesized compounds exhibit the inhibiting and bactericide activity against some bacteria and fungi. The highest activity has been established for the compounds 3 a, c, e-h, j against the strain Klebsiella pneumoniae (МІС=31.25 µg/mL). The calculated HOMO energy level proves that the compound 3 с is the most reactive ligand for the interaction with a protein receptor. The molecular docking data show that the compound 3 h has the highest affinity to the ThiM Klebsiella pneumoniae kinase.

The 4-bromomethyl-substituted thiazolium salts and corresponding thiazoles obtained through the condensation of 1,3-dibromoacetone with thioamide derivatives were utilised as efficient alkylating reagents for a series of thiophenols and heterylthiols. As a result, a small library of 4-thiomethyl-functionalised 1,3-thiazoles was synthesised in high yields, and their structures were characterised by ¹H, ¹³C NMR, LC-MS and IR spectra. Antioxidant activity of obtained compounds was studied in vitro using the DPPH test. The synthesised compounds showed high absorption level of DPPH radicals in the 70-98% range. For the most active derivatives 7e,m,p,t IC50 values were determined, which were in the range 191-417 µM (for ascorbic acid (reference) IC⁵⁰ value was 29 µM). Obtained radical scavenging activity screening data suggest in-depth study of the antioxidant potential for these types of heterocyclic compounds.

A series of new derivatives of 3-(pyrrol-4-yl)acrylamides 3a-l with the pyrrole nucleus functionalized by chlorine atoms and ester group, have been synthesized by simple preparative methods from the available esters of 5-chloro-4-formylpyrrol-3-carboxylic acids 1a-e. At first, 3-(pyrrol-4-yl)acrylic acids 2a-e were synthesized by the Knoevenagel’s reaction between malonic acid and the esters 1a-e. Then the target compounds were obtained with a high yield in the reactions between chloroanhydrides of the synthesized acrylic acids and aromatic or aliphatic amines in the boiling benzene. The structure of all obtained compounds was confirmed by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR spectroscopy, and additionally checked by the mass-spectrometry. Then the antimicrobial activity of all amides was tested in vitro on some gram-positive and gram-negative bacteria and fungi. It has been found that the gram-negative bacteria are resistant against the synthesized chemicals, while the gram-positive bacteria are sensitive to the amides 3с, e, f, g, i. The highest activity against Staphylococcus aureus MR and Staphylococcus epidermidis MS was registered for the amide 3f, and the retardation area diameter for this amide was greater than that for the control drugs.

Here derivatives of imidazo[2,1-b][1,3]thiazines are attractive objects for organic and medicinal chemists. In the present work chemoselective conditions for oxidation of the sulfur atom in the 6-(2-pyridinyloxy)substituted (benzo)imidazo[2,1-b][1,3]thiazines to the corresponding sulfoxides were proposed and their synthesis was performed. Synthesized sulfoxides exist in the diastereomeric mixture and individual diastereomers 2a-e and 3a-e were obtained using a chromatographic technique. The structure of compounds 2a-e and 3a-e were characterized using ¹H, ¹³C NMR, LC-MS spectra, and X-ray analysis for derivative 2b. The anti-inflammatory activity screening in vivo was performed using the carrageenan model of inflammatory paw edema in white rats for all the diastereomeric mixtures and individual diastereomers. Diastereomer 2c possessed an anti-inflammatory effect with an inflammation inhibition index of 46.1% which was equal to the activity of the reference drug diclofenac sodium.