Bioisosteric replacement of 1H-1,2,3-triazole with 1H-tetrazole ring enhances anti-leukemic activity of (5-benzylthiazol-2-yl)benzamides

Previously, we discovered that N-(5-benzyl-1,3-thiazol-2-yl)-4-(5-methyl-1H-1,2,3-triazol-1-yl)benzamide possessed a remarkable cytotoxic effect on 28 cancer cell lines with IC₅₀ < 50 μM, including 9 cancer cell lines, where IC₅₀ was in the range of 2.02-4.70 μM. In the present study, we designed a novel N-(5-benzylthiazol-2-yl)amide compound 3d that was synthesized using the original bioisosteric replacement of 1H-1,2,3-triazole ring by the 1H-tetrazole ring. A significantly enhanced anticancer activity in vitro with an excellent anti-leukemic potency towards chronic myeloid leukemia cells of the K-562 line was demonstrated. Two compounds - 3d and 3l - were highly cytotoxic at nanomolar concentrations towards various tumor cells of the following lines: K-562, NCI-H460, HCT-15, KM12, SW-620, LOX IMVI, M14, UACC-62, CAKI-1, and T47D. As a highlight, the compound N-(5-(4-fluorobenzyl)thiazol-2-yl)-4-(1H-tetrazol-1-yl)benzamide 3d inhibited the growth of leukemia K-562 cells and melanoma UACC-62 cells with IС₅₀ of 56.4 and 56.9 nM (SRB test), respectively. The viability of leukemia K-562 and pseudo-normal HaCaT, NIH-3T3, and J774.2 cells was measured by the MTT assay. Together with SAR analysis, it allowed the selection of a lead compound 3d, which demonstrated the highest selectivity (SI = 101.0) towards treated leukemic cells. The compound 3d caused DNA damage (single-strand breaks detected by the alkaline comet assay) in the leukemic K-562 cells. The morphological study of the K-562 cells treated with compound 3d revealed changes consistent with apoptosis. Thus, the bioisosteric replacement in (5-benzylthiazol-2-yl)amide scaffold proved to be a perspective approach in the design of novel heterocyclic compounds with enhanced anticancer potential.

Synthesis and biological evaluation of some new 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines as antimicrobial agents

A series of some new pyrazole-substituted 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines was synthesized in this study. The structures of target substances were confirmed by using 1H and 13С NMR spectroscopy, mass spectrometry and elemental analysis. The synthesized compounds have been evaluated for antimicrobial activity against five bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus) and two fungal strains (Candida albicans and Cryptococcus neoformans). The antimicrobial screening studies of synthesized substances established that 2 of 12 compounds show pronounced antibacterial activity against the strain Staphylococcus aureus.

Synthesis, anticancer and antimicrobial properties of some N-aryl-2-(5-aryltetrazol-2-yl)acetamides

The synthesis, anticancer and antimicrobial properties of novel N-aryl-2-(5-aryltetrazol-2-yl)acetamides were discussed. Novel N-aryl-2H-tetrazoles were synthesized and modified in order to obtain the compounds with a satisfactory pharmacological profile. The structures of target substances were confirmed by using 1H spectroscopy, mass spectrometry and elemental analysis. Anticancer activity screening was carried out within the framework of Developmental Therapeutic Program of the National Cancer Institute's (DTP, NCI, Bethesda, Maryland, USA). The compounds with significant levels of anticancer activities have been found that can be used for further optimization. The antimicrobial activity of the synthesized substances was evaluated by the value of the MIC and minimum fungicidal and bactericidal concentration. The findings exhibited that the compounds possessed moderate antimicrobial potential.

Synthesis and anticancer properties of 3-furan-2-yl-2-(4-furan/thiophen-2-ylthiazol-2-yl)acrylonitrile derivatives

By the reaction of (4-furan-2-yl-thiazol-2-yl)- 3a and (4-thiophen-2-yl-thiazol-2-yl)- 3b acetonitriles with furfural 4 and 5-arylfurfyrals 5a-g 3-furan-2-yl-2-(4-furan/thiophen-2-ylthiazol-2-yl)acrylonitrile derivatives 6a-i were obtained. Anticancer activity screening was carried out within the framework of Developmental Therapeutic Program of the National Cancer Institute's (DTP, NCI, Bethesda, Maryland, USA). It was found out that (2E)-3-(2-furyl)-2-[4-(2-furyl)-1,3-thiazol-2-yl]acrylonitrile (6a) and 2-(4-thiophen-2-yl-thiazol-2-yl)-acrylonitriles 6h,i possessed low activity and 2-(4-furan-2-yl-thiazol-2-yl)acrylonitrile derivatives 6b-g showed moderate action. Compounds 6b-g were sensitive to cell lines of MDA-MB-468 and T-47D Breast Cancer. In this case cytotoxic effect was observed with a range of GP = -38.24 – 1.28%.

Synthesis and biological evaluation of new 4-oxo-thiazolidin-2-ylidene derivatives as antimicrobial agents

In this study, an efficient synthesis and the antimicrobial activity evaluation of some 4-oxo-thiazolidin-2-ylidene derivatives are presented. The structures of the target substances were confirmed by using ¹ H and ¹³ C nuclear magnetic resonance spectroscopy, mass spectrometry, infrared spectroscopy, and elemental analysis. The synthesized compounds were evaluated for antimicrobial activity against five bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus) and two fungal strains (Candida albicans and Cryptococcus neoformans). It was shown that the compounds in this series possess antibacterial and antifungal activities.

Synthesis and anticancer properties of 5-(1H-benzoimidazol-2-ylmethylene)-4-oxo-2-thioxothiazolidin-3-ylcarboxilic acids

The reaction of 1H-benzoimidazole-2-carbaldehyde with 4-oxo-2-thioxothiazolidin-3-ylcarboxilic acids was studied and the combinatorial library of 5-(1H-benzoimidazol-2-ylmethylene)-4-oxo-2-thioxothiazolidin-3-ylcarboxilic acids has been prepared. The structures of target compounds 8a-f, 9 and 10a, b were confirmed by using 1H NMR spectroscopy and elemental analysis. The synthesized compounds were selected by the National Cancer Institute (NCI) Developmental Therapeutic Program for the in vitro cell line screening to investigate their anticancer activity. The tested compounds displayed a weak to medium anticancer activity. The most sensitive cell lines turned out to be SNB-75 of CNS Cancer (GP = 74.84–85.73%) and UO-31, Renal cancer (GP = 71.53–82.16%) and to compound 10a K-562 Leukemia cell lines (GP = 57.14).

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Synthesis and antimicrobial activity of 4-(5-ARYL-2-FUROYL)morpholines and 4-[(5-ARYL-2-FURYL)carbonothioyl] morpholines

By the reaction of furan-2-carboxylic acids and furfural with diazonium salts 1a-j the arylfuran-2-carboxylic acids 4a-e and 5-arylfuran-2-carbaldehydes 5a-f were synthesized. Acids 4a-e were transformed into appropriated acylchlorides 6a-e and were used for preparation of 4-(5-aryl-2-furoyl)morpholines 7a-e. 4-[(5-Aryl-2-furyl)carbonothioyl]morpholines 8a-f were prepared from aldehydes 5a-f by using Willgerodt-Kindler reaction. The structures of the obtained compounds were confirmed by 1H NMR spectroscopy and elemental analysis. All these new compounds gave spectroscopic data in accordance with the proposed structures. The antimicrobial activities of synthesized compounds 7a-e and 8a-f were investigated and the compounds with high activity against C. neoformans ATCC 208821 were identified.

Approaches for the synthesis, chemical modification and biological properties of N-acylphenothiazines

In this review we systematized the theoretical and experimental data concerning the versatile approaches for the synthesis of N-acylphenothiazines. The aim of the study was to compile the literature reported worldwide in the past 20 years. This article also reviewed the analysis of pharmacological activities of these heterocycles as one of the promising chemotherapeutic objects for the modern bioorganic and medicinal chemistry. It has been hypothesized that the enormous biological potential of these moieties is due to the radical nature in the acyl moiety. Therefore, the present review will be a good contribution to the literature and will provide the platform for the medicinal chemistry researchers to carry out more studies aiming the N-acylphenothiazine moieties as the novel chemotherapeutic agents.

3-Amino-5-(indol-3-yl)methylene-4-oxo-2-thioxothiazolidine Derivatives as Antimicrobial Agents: Synthesis, Computational and Biological Evaluation

Herein we report the design, synthesis, computational, and experimental evaluation of the antimicrobial activity of fourteen new 3-amino-5-(indol-3-yl) methylene-4-oxo-2-thioxothiazolidine derivatives. The structures were designed, and their antimicrobial activity and toxicity were predicted in silico. All synthesized compounds exhibited antibacterial activity against eight Gram-positive and Gram-negative bacteria. Their activity exceeded those of ampicillin and (for the majority of compounds) streptomycin. The most sensitive bacterium was S. aureus (American Type Culture Collection ATCC 6538), while L. monocytogenes (NCTC 7973) was the most resistant. The best antibacterial activity was observed for compound 5d (Z)-N-(5-((1H-indol-3-yl)methylene)-4-oxo-2-thioxothiazolidin-3-yl)-4-hydroxybenzamide (Minimal inhibitory concentration, MIC at 37.9–113.8 μM, and Minimal bactericidal concentration MBC at 57.8–118.3 μM). Three most active compounds 5d, 5g, and 5k being evaluated against three resistant strains, Methicillin resistant Staphilococcus aureus (MRSA), P. aeruginosa, and E. coli, were more potent against MRSA than ampicillin (MIC at 248–372 μM, MBC at 372–1240 μM). At the same time, streptomycin (MIC at 43–172 μM, MBC at 86–344 μM) did not show bactericidal activity at all. The compound 5d was also more active than ampicillin towards resistant P. aeruginosa strain. Antifungal activity of all compounds exceeded those of the reference antifungal agents bifonazole (MIC at 480–640 μM, and MFC at 640–800 μM) and ketoconazole (MIC 285–475 μM and MFC 380–950 μM). The best activity was exhibited by compound 5g. The most sensitive fungal was T. viride (IAM 5061), while A. fumigatus (human isolate) was the most resistant. Low cytotoxicity against HEK-293 human embryonic kidney cell line and reasonable selectivity indices were shown for the most active compounds 5d, 5g, 5k, 7c using thiazolyl blue tetrazolium bromide MTT assay. The docking studies indicated a probable involvement of E. coli Mur B inhibition in the antibacterial action, while CYP51 inhibition is likely responsible for the antifungal activity of the tested compounds.

A New Reagent for Spectrophotometric Determination of Ir(IV): 5-[2-(4-Hydroxyphenyl) hydrazineylidene]- 4-iminothiazolidin-2-one (HPIT)

The paper presents a new azolidone derivative - 5-[2-(4-hydroxyphenyl)hydrazineylidene]-4-iminothiazolidin-2-one (HPIT) studies and its interaction results with iridium(IV) ions. The Ir(IV) with this reagent in the pH = 5.0 without heating forms a stable complex (?max = 328 nm). The stoichiometric ratio of Ir(IV) to the reagent in complex is 1:1. The molar absorptivity and Sandell's sensitivity are 5.57×103 L mol-1 cm-1 and 0.034 µg cm-2 respectively. The calibration curve is linear in the range of 1.0-11.5 µg mL-1 of Ir(IV) (R = 0.9996). The limit of detection is 0.4 µg mL-1. Based on the conducted investigation a rapid and simple, spectrophotometric method for the determination of Ir(IV) using 5-[2-(4-hydroxyphenyl)hydrazineylidene]-4-iminothiazolidin-2-one as a chromophoric reagent was developed. The iridium(IV) was determined in various synthetic mixtures and alloys.

Anti-inflammatory properties of some novel thiazolo[4,5-b]pyridin-2-ones

Synthesis of novel N3 and C5 substituted thiazolo[4,5-b]pyridin-2-ones was carried out on the basis of [3+3]-cyclocodensation, acylation and alkylation reactions. The structures of the obtained compounds were confirmed by 1H NMR spectroscopy, and elemental analysis. The anti-inflammatory action of novel thiazolo[4,5-b]pyridine-2-one derivatives was evaluated in vivo employing the carrageenan-induced rat paw edema method. When compared with Ibuprofen, some our compounds were found to be more potent.

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Antioxidant properties of some novel derivatives thiazolo[4,5-b] pyridine

The synthesis and determination of the antioxidant activity of some novel (5,7-dimethyl-2-oxo-thiazolo[4,5-b]pyridine-3-yl)-acetic acid hydrazide derivatives are described in this article. The transformation of the base heterocycle was carried out via the reactions of acylation, [2+3]cyclocondensation, Knoevenagel condencation and alkylation for the purpose to obtain substances with a satisfactory pharmacological profile. Antioxidant activity of the synthesized compounds was evaluatedin vitroby means of the scavenging metod effect on 2,2 diphenyl-1-picrylhydrazyl (DPPH) radicals.

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Thermodynamic properties of methyl 4-(4-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate in organic solutions

The enthalpy and the entropy of dissolution of methyl 4-(4-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate in 2-propanol, ethyl acetate, acetonitrile, 2-propanone and benzene were determined from the temperature dependence of its solubility.The enthalpies and the entropies of mixing at 298 K were calculated taking into account the enthalpy of melting of the compound, determined via differential thermal analysis.The influence of the solvent on the solubility of the compound and on the corresponding enthalpy and entropy of mixing values was shown.

Tandem hetero-Diels–Alder-hemiacetal reaction in the synthesis of new chromeno[4′,3′:4,5]thiopyrano[2,3-d]thiazoles

Novel rel-(5aR,6R,11bS)-6-hydroxy-3,5a,6,11b-tetrahydro-2H,5H-chromeno[4′,3′:4,5]thiopyrano[2,3-d][1,3]thiazole-2-ones were synthesized via tandem hetero-Diels-Alder-hemiacetal reaction of 5-(2-hydroxybenzylidene)-4-thioxo-2-thiazolidinones and α,β-unsaturated aldehydes. The stereochemistry of cycloadditions was confirmed by NMR spectra and a single crystal X-ray diffraction analysis.

Synthesis of 1,2,3-Triazole Derivatives and Evaluation of their Anticancer Activity

Anticancer screening of several 1,2,3-triazoles with heterocyclic fragments has been performed. The 1,2,3-triazole derivatives were synthesized from available starting materials according to convenient synthetic procedures. The antitumor activity of the synthesized compounds was tested in vitro by the National Cancer Institute in NCI60 cell lines. It was observed that some compounds showed slight anticancer activity. One of them possessed a moderate activity against melanoma, colon, and breast cancer. Standard COMPARE analysis was performed at the GI₅₀ level.

1-{5-[2-Chloro-5-(trifluoromethyl)phenyl]thiophen-2-yl}ethanone

In the title molecule, C₁₃H₈ClF₃OS, the dihedral angle between the mean planes of 2-chloro-5-(trifluoro­meth­yl)phenyl and tiophene rings is 54.37 (5)°. The acethyl group is twisted by 8.1 (2)° with respect to the thio­phene ring. The CF₃ group is disordered over two sets of sites with occupations of 0.49 (3) and 0.51 (3). The crystal packing features C—H⋯F and C—H⋯O hydrogen bonds, forming dimers which are connected into chains along the c axis by C—H⋯O hydrogen bonds and C—Cl⋯π [Cl⋯π = 3.415 (1) Å and C—Cl⋯π = 151.56 (5)°] inter­actions. The chains are further connected into layers perpendicular to the a axis by C—H⋯O inter­actions.

3-(4-Chloro-phen-yl)-2,1-benzisoxazole-5-carbonyl chloride

The molecule of the title compound, C(14)H(7)Cl(2)NO(2), is not planar; the dihedral angle between the mean planes of the chloro-phenyl and benzisoxazole rings is 20.32 (7)°. The carbonyl chloride group is twisted with respect to the benzisoxazole ring by 2.5 (1)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯Cl hydrogen bond. In the crystal packing, adjacent mol-ecules are linked into dimers by inter-molecular C-H⋯O hydrogen bonds. The dimers are further stacked into columns along the unique axis direction by π-π stacking inter-actions, with a centroid⋯centroid distance of 3.828 (5) Å. Other weak inter-molecular C-H⋯O and C-H⋯Cl inter-actions are also present.