Synthesis, complexation, and fluorescence behavior of 3,4-dimethylthieno[2,3-b]thiophene carrying two monoaza-15-crown-5 ether groups

Synthesis and Characterization of Two Novel Oxazol-5-ones Derivatives and Their Multifunctional Properties; pH Sensitivity, Electropolymerizability and Antiproliferative Activity

The aim of this study is to synthesize oxazol-5-one derivatives, which have multi-functional properties. Nomenclatures of newly synthesized molecules are 4-(4-N,N-diethylaminophenylmethylene)-2-(3-thienyl)oxazol-5-one (4a) and 4-(4-(1,4,7,10-tetraoxa-13-azacyclopentadecyl)phenylmethylene)-2-(3-thienyl)oxazol-5-one (4b). These two novel derivatives contain pH sensitive and polymerizable groups. 3-Thienyl group was attached to position-2 of the oxazol-5-one ring to provide electrochemical polymerization capability. pH sensing properties were provided by attaching p-N,N-diethylaminophenylmethylene and p-aza-15-crown-5-phenylmethylene groups to the arylmethylene moiety at position-4 of the ring. Target molecules were synthesized by classical process known as Erlenmeyer-Plöchl Azlactone Synthesis Erlenmeyer (Justus Liebigs Ann Chem 275:1-12, 1893), Rodrigues et al. (J Chem Educ 92:1543-1546, 2015) . After structural characterization of 4a and 4b, absorption and emission characteristics were determined in solvents that have different polarities. Difference in maximum absorption and emission wavelengths of the molecules related to solvent polarities were observed at around 6-7 nm and 35-36 nm respectively. In pH studies of the target derivatives in PVC polymer matrix, ratiometric changes were observed at isosbestic point around 398 nm. Polymeric depositions of the molecules (4a, 4b) were proved by using cyclic voltammetry, electrochemical impedance spectrometry studies and scanning electron microscope images. MTT assay studies showed significant results like, 4b derivative's strong cytotoxic activity on PC-3 (cancerous cell line) with IC₅₀ value of 12.57 ± 0.41 µg/ml without exhibiting any cytotoxic effect on HEK293 (healthy cell line).

Investigation of cation binding and sensing by new crown ether core substituted naphthalene diimide systems

Different modes of cation binding lead to very different optical readouts from two structurally similar sensors.

Design, synthesis and fluorescence behavior of novel chemosensor with a thieno[2,3-b]thiophene fluorophore

A novel chemosensor with a thieno[2,3-b] thiophene fluorophore bearing an oxazoline receptor exhibited good selectivity to the dichromate anion, and also shows enantioselectivity for mandelic acid with a chiral receptor.

Synthesis, reactions and biological activity of some new bis-heterocyclic ring compounds containing sulphur atom

BACKGROUND

The derivatives of thieno[2,3-b]thiophene belong to a significant category of heterocyclic compounds, which have shown a wide spectrum of medical and industrial application.

RESULTS

A new building block with two electrophilic center of thieno[2,3-b]thiophene derivatives 2 has been reported by one-pot reaction of diketone derivative 1 with Br2/AcOH in excellent yield. A variety of heteroaromatics having bis(1H-imidazo[1,2a] benzimidazole), bis(1H-imidazo[1,2-b][1,2,4]triazole)-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives, dioxazolo-, dithiazolo-, and 1H-imidazolo-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives as well pyrrolo, thiazolo -3-methyl-4-phenylthieno[2,3-b]thiophene derivatives have been designed, synthesized, characterized, and evaluated for their biological activity. Compounds 3-9 showed good bioassay result. These new derivatives were evaluated for anti-cancer activity against PC-3 cell lines, in vitro antioxidant potential and β-glucuronidase and α-glucosidase inhibitory activities. Compound 3 (IC50 = 56.26 ± 3.18 μM) showed a potent DPPH radical scavenging antioxidant activity and found to be more active than standard N-acetylcystein (IC50 = 105.9 ± 1.1 μM). Compounds 8a (IC50 = 13.2 ± 0.34 μM) and 8b (IC50 = 14.1 ± 0.28 μM) found as potent inhibitor of α-glucusidase several fold more active than the standard acarbose (IC50 = 841 ± 1.73 μM). Most promising results were obtained in β-glucuronidase enzyme inhibition assay. Compounds 5 (IC50 = 0.13 ± 0.019 μM), 6 (IC50 = 19.9 ± 0.285 μM), 8a (IC50 = 1.2 ± 0.0785 μM) and 9 (IC50 = 0.003 ± 0.09 μM) showed a potent inhibition of β-glucuronidase. Compound 9 was found to be several hundred fold more active than standard D-Saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 μM).

CONCLUSIONS

Synthesis, characterization, and in vitro biological activity of a series of thieno[2,3-b]thiophene have been investigated.

A facile and convenient synthesis of some novel hydrazones, Schiff's base and pyrazoles incorporating thieno[2,3-b]thiophenes

A facile and convenient synthesis of some novel hydrazones, schiff's base and pyrazoles from thieno[2,3-b]thiophene derivatives 1 have been achieved in high yields assisted by microwave and classical methods. The structures of all the title compounds have been elucidated by elemental analysis, IR, MS, (1)H-NMR and (13)C-NMR. Generally, these findings represent a new class of sulfur and nitrogen moieties that should also be of interest as new materials.