New Ketene Dithioacetals Generated from 2-Nitroperchlorobutadiene and Investigation of Their Antibacterial, Antifungal, Anticonvulsant and Antidepressant Activities.

The ketene dithioacetal 3 generated from 2-nitroperchlorobutadiene 1 reacted with various heterocyclic amines and aliphatic, aromatic and heterocyclic thiols to produce functionalized new ketene-N,S,S-acetals and S,S,S-acetals 4a-f, 5a-h as heterocyclic dithiolanes. They were separated/purified by chromatographic methods and their exact structure characterization were made clear by spectroscopic methods. These compounds synthesized could act as effective drugs for versatile activity. Evaluation of the antimicrobial effect of the obtained substances determined derivatives 4e and 5h, which have MIC=15.6 µg/mL for the test culture of Mycobacterium luteum bacteria closing to the control drug Vancomycin. The obtained compounds can be proposed as a promising synthetic objects for future molecular design to enhance the antimicrobial action. Ketene dithioacetals 3, 4a, 4b, 4e, 5g (50 mg/kg) exhibited antiseizure effect comparable with reference drug (valproic acid) on the model of pentylenetetrazole-induced convulsions after single oral administration both at 3 h and 24 h. Furthermore, tested dithioacetals possessed prolonged antidepressant activity in forced swim test (FST) considerable decreasing the duration of immobility time compared to reference drug amitriptyline. This is the first study of the investigation of anticonvulsant and antidepressant activities of ketene dithioacetals.

Synthesis and antimicrobial properties of 4-acylaminobenzenethiosulfoacid S-esters.

A series of esters of 4-acetyl, 4-trifluoroacetyl- and 4-(3-chloropropionyl)aminobenzenethiosulfoacids (twenty-four compounds) were synthesized and characterized by elemental analysis, 1H NMR and IR spectroscopy. The antibacterial activity of the novel candidates has been screened using the agar diffusion or serial dilution methods against representative Gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus mesentericus, Mycobacterium sp., Mycobacterium luteum), Gram-negative (Aeromonas sp., Burkholderia cepacia, Alcaligenes faecalis, Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris) bacteria and fungi (Candida albicans, Candida tenuis, Candida glabrata, Verticillium dahliae, Trichophyton gypseum, Aspergillus niger, Aspergillus fumigatus, Penicillium chrysogenum). Particular potency has been discovered against all tested pathogenic bacteria and fungi by compounds 1l and 3l at nanomolar concentrations. Some appropriate effect of thiosulfoesters structure upon their antimicrobial activity was determined.

Design, Synthesis, Biological Evaluation, and Antioxidant and Cytotoxic Activity of Heteroatom-Substituted 1,4-Naphtho- and Benzoquinones.

In the present paper, we report the synthesis, characterization, and biological evaluation as antifungal, antibacterial, antioxidant, and cytotoxic/anticancer agents of N-, S-, O-substituted-1,4-naphtho- and 2,5-bis(amino-substituted)-1,4-benzoquinone derivatives. In the synthesized compounds, antimicrobial activity at low concentrations against Escherichia coli B-906, Staphylococcus aureus 209-P, and Mycobacterium luteum B-917 bacteria and Candida tenuis VKM Y-70 and Aspergillus niger F-1119 fungi in comparison with controls was identified. 2-(N-Diphenylmethylpiperazin-1-yl)-3-chloro-1,4-naphthoquinone 9a was the most potent, with a minimum inhibitory concentration value of 3.9 µg/mL against test culture M. luteum. The synthesized compounds were screened for their antioxidant capacity using the cupric-reducing antioxidant capacity (CUPRAC) method. 2,2'-[1-(2-Aminoethyl)piperazin-1-yl]-3,3'-dichloro-bis(1,4-naphthoquinone) 10 showed the highest antioxidant capacity, with a 0.455 CUPRAC-trolox equivalent antioxidant capacity (TEAC) coefficient. Other parameters of antioxidant activity (scavenging effects on OH(·), O2(·ï¼), and H2O2) of these compounds were also determined. The cytotoxic activity of the compounds was investigated by employing the sulforhodamine B cell viability assay against A549 (lung), MCF-7 (breast), DU145 (prostate), and HT-29 (colon) cancer cell lines. Compound 10 exhibited the most powerful cytotoxic activity at a concentration of 20 µM against all cell lines. In addition to the strongest antioxidant activity of compound 10, it also had lowest IC50 values (<3 µM), warranting further in vivo studies due to its anticancer activity.

Synthesis and antimicrobial activity of N-substituted-ß-amino acid derivatives containing 2-hydroxyphenyl, benzo[b]phenoxazine and quinoxaline moieties.

3-[(2-Hydroxyphenyl)amino]butanoic and 3-[(2-hydroxy-5-methyl(chloro)phenyl)amino]butanoic acids were converted to a series of derivatives containing hydrazide, pyrrole and chloroquinoxaline moieties. The corresponding benzo[b]phenoxazine derivatives were synthesized by the reaction of the obtained compounds with 2,3-dichloro-1,4-naphthoquinone. Five of the synthesized compounds exhibited good antimicrobial activity against Staphylococcus aureus and Mycobacterium luteum, whereas three compounds showed significant antifungal activity against Candida tenuis and Aspergillus niger.

Synthesis and microbiological evaluation of new 2- and 2,3-diphenoxysubstituted naphthalene-1,4-diones with 5-oxopyrrolidine moieties.

New 3-substituted 1-(3-hydroxyphenyl)-5-oxopyrrolidine derivatives containing hydrazone, azole, diazole, oxadiazole fragments, as well as 2-phenoxy- and 2,3-diphenoxy-1,4-naphthoquinone derivatives were synthesized. The structure of all compounds has been confirmed by NMR, IR, mass spectra, and elemental analysis data. Methyl 1-{3-[(3-chloro-1,4-dioxo-1,4-dihydro-2-naphthalenyl)oxy]phenyl}-5-oxo-3-pyrrolidinecarboxylate demonstrated potential antibacterial and antifungal activities as determined by diffusion and serial dilution methods, while N'-[(4-bromophenyl)methylidene]-1-{3-[(3-chloro-1,4-dioxo-1,4-dihydro-2-naphthalenyl)oxy]phenyl}-5-oxo-3-pyrrolidinecarbohydrazide and 2-{3-[4-(1,2,3-oxadiazol-5-yl)-2-oxo-1-pyrrolidinyl]phenoxy}-3-{3-[4-(1,3,4-oxadiazol-2-yl)-2-oxo- 1-pyrrolidinyl]phenoxy}naphthoquinone showed antifungal activity against Candida tenuis and Aspergillus niger at low concentrations, as determined by the serial dilution method. The substitution of the methoxy fragment by N-containing substituents in monophenoxy substituted naphthoquinones was found to decrease their activity against Mycobacterium luteum. Besides, introduction of the second phenoxy substituted fragment increased the antifungal activity against Candida tenuis and Aspergillus niger at lower concentrations.

Synthesis and biological evaluation of novel nitrogen- and sulfur-containing hetero-1,4-naphthoquinones as potent antifungal and antibacterial agents.

1,4-Naphthoquinones are unique reagents in organic synthesis and have been employed in several well known and recently developed areas of application. Furthermore, these 1,4-naphthoquinones have demonstrated high reactivity in nucleophilic vinylic substitutions, in the preparation of sulfurated, (hetero)cyclic and several other transformations. This study describes the synthesis and biological evaluation of derivatives of monosulfurated naphthalene-1,4-dione (3), 3-chloro-2-ethoxy-naphthalene-1,4-dione (4), disulfurated naphthalene-1,4-dione (5), and symmetrical bis-1,4-naphthoquinones (7, 9) were obtained from the reaction of 2,3-dichloro-naphthaquinone (1) with S-, O-substituted mono-, di-, and tetrathiols, respectively. The structures of the novel products were characterized by spectroscopic methods.