A preparatively convenient method is proposed for the synthesis of new 1-oxo-3,4-dihydro-1H-pyrrolo[2,1-с][1,4]oxazine-8- 4a-e and 4-oxo-4H-pyrrolo[2,1-c][1,4]benzoxazine-3-carboxylic acids 5a-f that is based on the interaction of methyl (2-oxomorpholin-3-ylidene)ethanoates 1a-e and methyl (2-oxo-2H-1,4-benzoxazine-3(4H)-ylidene)ethanoates 2a-f with 2-bromo-1,1-diethoxyethane. Obtained acids were transformed into the corresponding tert-butyl carbamates 6a-e, 7a-f and N-alkyl(aryl)carboxamides 11a-i, 12a-d. By treating tert-butyl carbamates 6a-e, 7a-f with hydrogen chloride, 8-amino-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazin-1-ones 8a-e and 3-amino-4H-pyrrolo[2,1-c][1,4]benzoxazin-4-ones 9a-f were obtained. By acylation of amines 8a-e, 9a-f with acetic anhydride, benzoyl chloride, methanesulfonyl chloride, and p-toluenesulfonyl chloride, corresponding N-acetamides 13a,b, 14, N-benzamides 15, 16, N-methanesulfonamides 17, 18, and N-p-toluenesulfonamides 19, 20 were synthesized. In total, 30 new derivatives of 1-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazinones and 27 new 4-oxo-4H-pyrrolo[2,1-c][1,4]benzoxazinones were obtained.

A number of 3-aryl-5,6-dihydroimidazo[2,1-b][1,3]thiazoles were synthesized by cyclocondensation of imidazolidine-2-thione with phenacyl bromides, and their antimicrobial and antioxidant activity was evaluated. Bioscreening confirmed the moderate antibacterial activity against the reference strains of bacteria Staphylococcus aureus, Escherichia coli and Proteus vulgaris and excellent antifungal activity against Candida albicans. It was found that 3-(4-chlorophenyl)-5,6-dihydroimidazo[2,1-b]thiazole 4h (MIC = 15.625 μg/ml) has twice the antifungal effect compared to the control drug Furacilin. The study of the antioxidant activity of the synthesized compounds proved their ability to inhibit 60–97% of DPPH radicals. The best antiradical effect was found for 4-(5,6-dihydroimidazo[2,1-b]thiazol-3-yl)phenol 4e (I = 97%). A probable mechanism of its action was proposed involving the formation of a radical cation by the SET process. For the most active antioxidants 4e-g, reactivity and electrostatic surface potential were evaluated using the DFT method, and molecular docking was studied on the human peroxiredoxin 5 protein model.

By the reaction of substituted benzaldehydes and indol-3-carbaldehydes (2E)-2-cyano-N-[5-(R-benzyl)-1,3-thiazol-2-yl]-3-(R1-phenyl)prop-2-enamides 3-(1-R¹-1H-indol-3-yl)-2-cyano-N-(5-(R-benzyl)-1,3-thiazol-2-yl)prop-2-enamides were synthesised. The antitumor activity of prepared compounds were investigated. 3-(1-Benzyl-¹H-indol-3-yl)-2-cyano-N-(5-(2-chlorobenzyl)-1,3-thiazol-2-yl)prop-2-enamide (7b) has been identified as hit compound with values of MG-MID GI50 = 3.903 µM, TGI = 29.10 µM, LC50 = 57.54 µM.

Fourteen novel 4-(5-amino-4-cyano-1,3-oxazol-2-yl)benzenesulfonamides have been designed, synthesized, and characterized by spectroscopy and spectrometry methods. They have also been investigated on the NCI-60 cancer cell lines. The most activity compounds, 2, 3, and 9, in concentration 10 µM demonstrated mean GI50 values of 77, 70, and 68%, respectively, against the tumor cells. The best activity compound 2 showed the following GI50 values: non-small cell lung cancer (HOP-92) - 4.56 µM, breast cancer (MDA-MB-468) - 21.0 µM, melanoma (SK-MEL-5) - 30.3 µM. Besides, this compound indicates low toxicity with TGI and LC50 values >100 µM against all cancer cell lines. The COMPARE analysis (NCI) of compound 2 showed a very high correlation (r=0.91) with Tamoxifen as a selective estrogen receptors modulator. Molecular docking studies of ligand 2 demonstrated the complexation with estrogen receptors as a possible antitumor mechanism. The ADMET analysis of compound 2 indicates an optimistic prediction as an antitumor agent.

This short communication reports about new 5-amino-4-(1H-tetrazol-5-yl)-1,3-oxazoles which were synthesized by [3+2] cycloaddition of 2-R-5-amino-1,3-oxazole-4-carbonitriles and trimethylsilyl azide with dibutyltin oxide present. The reaction conditions provided high yields of the products, and were tolerant to some active functional fragments in the oxazole substituents (amino, amido, and hydroxy group). In the case of 2-((4-cyano-2-phenyloxazol-5-yl)amino)-N-methylacetamide the by-product (N-((1-(2-(methylamino)-2-oxoethyl)-1H-tetrazol-5-yl)(1H-tetrazol-5-yl)methyl)-benzamide) was formed together with the expected tetrazolyloxazole.

It has been reported that the halogen dance reaction can be used to synthesize polyfunctionalized 1,3-thiazoles. The transformation into target products was carried out by lithiation of 2-bromo-5-(1,3-dioxolan-2-yl)-1,3-thiazole with lithium diisopropylamide (LDA) followed by treatment with various electrophiles. The obtained compounds were then successfully applied to prepare novel 4,5-difunctional thiazole derivatives.

Triazolo[3,4-b]thiadiazoles are a class of heterocyclic compounds, which have attracted great interest in medicinal chemistry owing to their wide range of pharmacological activities. A number of triazoles fused to thiadiazoles are incorporated into a wide variety of therapeutically important compounds possessing a broad spectrum of biological activities. Considering such a significant pharmacological potential, as well as wide synthetic possibilities triazolo-thiadiazoles have received considerable attention from scientific community and are extensively used for construction of prospective drug-likes molecules. In this review, we summarized the literature data about the main synthetic approaches for obtaining condensed heterocyclic compounds based on triazolo[3,4-b][1,3,4]thiadiazole scaffold as promising objects for modern bioorganic and medicinal chemistry.

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.

Novel 2,4-disulfonylsubstituted 5-aminothiazoles were synthesized and their anticancer activity was assessed at a high dose (10 μM) against NCI 60 cancer cell lines. Compounds 24 and 25 showed the antiproliferative activity with mean growth inhibition about 66.0%. Replacing 4-hydroxypiperidine 24 with the more hydrophilic N-methyl piperazine 25 increased the number of sensitive cell lines while replacing these hydrophilic groups with lipophilic ones abolished the anticancer activity. The COMPARE analysis showed that the tested compounds had a moderate positive correlation with alkylating agents (CCNU and methyl CCNU) and with a purine nucleotide biosynthesis inhibitor analog (L-cysteine). The results indicate that the above mechanisms of antitumor action of standard compounds are not the main ones for the tested compounds due to the lack of a high correlation. The results of this study allow us to consider compounds 24 and 25 as a basis for their further functionalization to obtain more active compounds.

Rhodanines are recognized as privileged heterocycles in medicinal chemistry. The main achievements include the development of drug-like molecules with numerous biological activities as well as approved drugs. The Furan nucleus is considered one of the promising heterocyclic cores in medicinal chemistry that showed numerous ranges of activity. The combination of several heterocycles in a one molecule commonly provides much more interest in the enhanced activity profile of its analogs than their parent separate constituents. Such conjugates are promising objects for modern medicinal chemistry. In this review paper recent advances in the synthesis and biological activities rhodanine-furan conjugates which its application in the different field of drug discovery.