Thiophene containing molecules have been distinguished as potential candidates in the largely emergent chemical world of heterocyclic compounds that show likely pharmacological characteristics. The knowledge of a mixture of synthetic pathways and the different physicochemical parameters of such compounds describe the especial interest of medicinal chemists to produce combinatorial collections and carry out in-depth efforts in the search of lead molecules. Among the various group of compounds studied, thiophene moieties stand out as unique in features due to their biological, pharmacological and medicinal properties. Synthesis, crystal structure, conformation and density functional theory of 2-(2-phenylanthracen-9-yl)thiophene derivative have been investigated in detail. Thiophene moiety are in planar conformation and having C-H…O type of hydrogen bonds and Van der Waals forces. Density functional theory has been applied to the thiophene derivative. Thiophene compounds score highly against the targeted protein and can be compared to the co-crystal ligand. Hirshfeld surface studies have been used to confirm and quantify the supramolecular features.
The green chemistry approach provides for the synthesis of coumarin-1,4-dihydropyridine scaffolds 6a-o via sequential multicomponent reaction using catalytic amount of triethylamine (TEA). These new coumarin scaffolds have been successfully explored for the effective inflammatory as well as microbial infection inhibitors. The antimicrobial activity results of the title compounds have shown potent activity against both gram positive and gram negative bacterial, and fungal stains. Additionally, anti-inflammatory activity of all the compounds has been found to be quite promising in comparison with standard Diclofenac sodium. Furthermore, the in silico docking study has been performed for all the compounds with S. aureus DNA gyrase and cyclooxygenase-2 (PDB ID 4PH9). The computational results are in good agreement with the in vitro antibacterial and anti-inflammatory experimental results.
The current project deals with designing and synthesizing of colourimetric chemosensors to detect the cations in the aqueous medium and biological sample. To achieve this goal a new series of quinazolinone derivatives have been synthesized via reaction of the novel 6-nitro-2-propy1-4H-benzo[d][1,3]oxazin-4-one 3 with selected nitrogen nucleophiles, namely, formamide, hydrazine hydrate, hydroxylamine hydrochloride, o-phenylendiamine, o-aminophenol and o-aminothiophenol, urea and/or thiourea. Structures of the new compounds have been investigated depending on their spectral data (IR, H-1 and C-13 NMR and MS) and elemental analyses. Some of the newly synthesized products exhibit significant response as chemosensors for a few cations detection.
In recent years, the thioisatin (benzo[b]thiophene-2,3-diones) have attracted considerable attention due to their ability to act as intermediates in the preparation of a series of fused spiroheterocycles. The benzothiophenic frameworks are important targets in synthetic and medicinal chemistry because this fragment is a key moiety in a wide number of natural and synthetic agents. Subsequently the present study deals with the synthesis of a variety of spiroheterocycles for which different strategies have been evolved viz. [4+2] photocycloaddition (spiropyrans), cyclocondensation (benzodiazocine), nucleophilic cyclization (spirothioazolidinones) and air oxidation (disulfides). semicarbazide reacts with thioisatin at 3‑position (thiosemicarbazones, 2-hydroxy-(2 H )-3,3-diaryl- and 3-hydroxy-3 H -2,2-diaryl-benzo[b]thiophenes hydroxyl compounds), 4,9-dimethylthiophanthrenes.
Schiff bases are versatile organic compounds, gaining importance day by day due to their wide applications. Schiff bases, containing imines or azomethine functional groups, are prepared by condensation of primary amines with carbonyl compounds or they may occur naturally in plants. They have lots of importance in industry and show numerous biological activities including antibacterial, antifungal, antiviral, anticancer, etc. The wide range of biological studies of the Schiff bases are now attracting the attention of researchers which can lead to the identification of promising lead compounds. This review consists of the recent developments and various methodologies to synthesize Schiff base as well as their biological activities covering the last 20 years.
A very simple and convenient one-pot synthesis of Spiro-3,4-dihydro-2H-pyrrole has been developed while synthesizing 2,2,5-trisubstituted pyrrolidines.Initially, the Meldrum's acid was treated with ,-unsaturated ketones in presence of anhydrous carbonate base and phase transfer catalyst benzyltriethylammonium chloride in acetonitrile as a solvent to afforded the Michael adduct which was readily converted to the corresponding oxime using standard conditions.The crude oxime was treated directly with p-toluenesulfonyl chloride to tosylate the oxime but instead in presence of an excess of organic base as Et3N results in tandem nucleophilic cyclization to spirobicyclic compound as Spiro-3,4-dihydro-2H-pyrrole as product directly, instead of the tosyloxime.So, it was considered to be a novel route to synthesized spirocyclic compounds as it is the skeleton of many natural products and pharmaceutical products.
Non-digestible oligosaccharides are associated with positive health outcomes; however, hemicellulosic oligosaccharides of N. arbor-tristis have not been studied. Herein, we report production of hemicellulosic oligosaccharides from its leaves and their identification. A series of complex neutral oligosaccharides (1-16), produced by endo-(1,4)-beta-D-glucanase digestion of the alkali extracted xyloglucan, have been identified by chemical, HPAE chromatographic and MALDI-mass spectrometric techniques. Additionally, xylan enriched hemicellulose-A fraction upon endo-(1,4)-beta-D-xylanase digestion yield several acidic and neutral xylo-oligosaccharides (17-24), each containing a backbone of beta-(1,4)-D-Xylp units substituted at position 2 with a single stub of D-Xylp or 4-O-Me-D-GlcpA residues. The structural diversity and high water solubility of these enzyme-generated oligosaccharides suggested promising health implications.
A new series of novel 3-(5-aryl/aryloxy methyl-1,3,4-thiadiazol-2-yl)-spiro-cyclohexane-1'2-thiazolidin-4-ones have been synthesized from a common intermediate, in good yields. These compounds have been screened for their antibacterial and antifungal activity against different pathogenic strains of bacteria and fungi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined for the test compounds as well as for reference standards. Compounds 3c, 3d, 6c and 6d have shown good antibacterial activity where as compounds 3a, 3b, 6a and 6b have displayed better antifungal activity.
Two new series 2-(2-(1-(1-methyl-1H-benzo[d]imidazol-2-yl)ethylidene)hydrazinyl)-4-(aryl)thiazoles 3a-k and 2-(2-(1-(1-methyl-1H-benzo[d]imidazol-2-ypethyphydrazinyl)-4-(arypthiazoles 4a-k encompassing benzimidazole incorporated with thiazole have been synthesized using rational approach. These thiazole derivatives 3a-k have been reduced at the site of formation of Schiff base (>CH=NO) to obtain final compounds 4a-k. Compounds 3a-k and 4a-k have been screened for their in vitro antibacterial and antifungal actions against four strains each. Among the screened compounds, 3d, 3e, 3f, 3g, 3j, 3k, 4d, 4e, 4f and 4k have emerged as highly effective antibacterial agents, while compounds 3d, 3e, 3f, 3k and 4k have come out as most potent antifungal molecules. Comparison of outcomes of antibacterial and antifungal screening of compounds 3a-k and 4a-k directed that antimicrobial potential of unreduced derivatives 3a-k is higher than reduced derivatives 4a-k. SAR study reveals that presence of halogen (-F, -Cl, -Br) substituents is accountable for significant antimicrobial potential. Also the results of preliminary MTT cytotoxicity assay on HeLa cells indicates that antimicrobial activity of 3e, 3f, 3g, 3j, 3k, 4e, 4f and 4k is accompanied by low extent of cytotoxic concentrations.
The adducts 4a,b-7a,b have been obtained either by reducing alpha-chloro-beta-oxosulfenyl chlorides 2a,b with iodide ion in the presence of dienes namely, 2-methyl-1,3-butadiene (isoperene), 2,3-dimethyl-1,3-butadiene, 1,2,3,4-tetrachlorocyclopentadiene, or 1,3-cyclohexadiene, respectively; or by thermolysis of oxadithiin derivatives 3a,b in the presence of the same aforementioned dienes presumably via the formation of the same intermediate A in both cases of compounds 2a,b and 3a,b. It is observed that alpha-chloro-beta-oxosulfenyl chlorides 2a,b undergo straight forward substitution with potassium cyanide to give 8a,b. Direct oxidation of 2a,b with H2O2/AcOH affords 3,3-dichloropyran-4-ones 9a,b, while conversion of 2a,b to the sulfonamides 10a,b followed by oxidation provides 3-chloropyranones 11a,b. Antioxidant and antimicrobial evaluation of compounds 4a,b-6a,b shows moderate activiy. MIC of the derivative 6b reveals a remarkable inhibition of the pathogenic gram positive bacteria (Staphylococcus aureus) as well as gram negative E coli.
A new series of benzothiazole linked isoxazole Schiff base derivatives have been prepared and characterized by suitable spectroscopic methods via 1H and 13C NMR, ESI-MS and IR spectra. These compounds have been further screened for their antimicrobial activity against a panel of microorganisms. Among them, compounds 12d, 12g and 12l demonstrate promising antimicrobial activity against all the tested strains with MIC values ranging between 3.9 – 62.5 µg/mL. Further, compounds 12d, 12g and 12l exhibit promising antifungal activity with MIC values ranging between 7.8 – 32.5 µg/mL. Further studies are underway for determining the antifungal molecular mechanisms of these potential compounds.
One-pot synthesis of novel derivatives of bis-chalcones has been achieved by condensation of 1,4-diacetylbenzene with different aldehydes in basic media. The reaction of chalcone derivatives 3a,b with thioglycolic acid gives compounds 4a,b. This, when reacted with ethyl cyanoacetate in presence of ammonium acetate gives the corresponding cyanopyridine derivatives 5a,b. Furthermore, bis-chalcone 3a,b has been cyclized to pyrazole analogs by using 2,4-dinitrophenylhydrazine to give compounds 7a,b in good yields. All products have been characterized by IR, H-1 and C-13 NMR, and elemental analysis. The newly synthesised compounds have been screened for anti-bacterial activity
A facile and highly efficient one pot multi-component reaction for the synthesis of 2-thio-5-arylbenzo [4,5]thiazolopyrimido[5,4-d]pyrimidin-4-one derivatives 4 under aqueous medium has been developed. The reaction takes place by condensation of thiobarbituric acids 1, 2-aminobenzothiazole 2 and aldehydes 3 using metal-proline catalyzed domino Knoevenagel, Michael and intramolecular cyclization approach.
In the present investigation, a series of novel (Z)-5((5-chloro-1H-indol-3-yl)methylene)thiazolidine-2,4-dione analogues have been designed and synthesized in good yields with the objective of selective N-alkylation at thiazolidine 2,4-dione ring in competence with indole ring under basic conditions in the presence of aprotic solvent dimethylformamide (DMF). The newly synthesized compounds have been characterized by spectral data (IR, H-1 and C-13 NMR, NOE, NOESY, H-1-H-1-COSY and LC-MS). Further, molecular docking and ADME studies have revealed that the newly synthesized compounds have very good docking score against antidiabetic and anti-inflammation activities (PPARy and COX-2) as compared with standard rosiglitazone.
A new series of novel 1, 4-disubstituted-3-methyl pyrazolo [4,3-e]-pyrido [1,2-a] pyrimidines have been synthesized from a common intermediate, in good yields. These compounds have been screened for their antibacterial and antifungal activity against different pathogenic strains of bacteria and fungi. The minimum inhibitory concentration (MBC) and minimum fungicidal concentration (MFC) have been determined for the test compounds as well as for reference standards. Compounds 3d, 3e, 3f, 3h have shown good antibacterial activity whereas compounds 3a, 3b, 3c, 3g have displayed better antifungal activity.
