Synthesis of new 3,4-dihydropyrano[c]chromene derivatives and their evaluation as acetyl cholinesterase inhibitors

2-Amino-4-phenyl-4,5-dihydro-5-oxopyrano[2,3-c]chromen-3-carbonitrile derivatives (8a-d) have been isolated in good yields by the reaction of corresponding 4-hydroxycoumarin (1) with substituted aldehydes (2a-d) and malononitrile (3) under reflux conditions. The reactivity of α-functionalized iminoethers (9a-d) with hydrazine, hydroxylamine and piperidine was studied. The synthesized compounds were characterized by various techniques including spectroscopy. Compounds 8-11 were also evaluated as potential acetylcholinesterase inhibitors

Synthesis, crystal structures and spectroscopic investigation of new Cu/Schiff-base complexes

Three novel Copper complexes, [Cu(L1)2][CuCl2] (1),  [Cu(L2)Cl] (2) and [Cu2(L3)3Cl2] (3), have been prepared by reaction of CuCl with the Schiff-base ligands L1: N,N’-bis(thiophen-2-ylmethylene)-ethane-1,2-diamine, L2: N,N’-bis(1H-pyrrol-2-ylmethylene)ethane-1,2-diamine and L3: N,N’-bis(2-nitrobenzylidene)-ethane-1,2-diamine in acetonitrile. The solid-state structures of these complexes were determined by X-ray diffraction from single crystal data and characterized by 1H and 13C NMR, IR and UV/Vis spectroscopies. This study shows that (1) is an ionic complex with a Cu(I)-centered cation and an isolated linear dichlorocuprate(I) anion, (3) is a dinuclear neutral complex of Cu(I) while (2)  is a mononuclear neutral complex of Cu(II). In the three complexes, Cu is tetracordinated in different geometrical environments. The atomic arrangements and spectroscopic properties of the three complexes are reported. Complexes 1-3 exhibit, in the solid state at room temperature, photoluminescence between 320 and 550 nm

Novel antimicrobial and anti-acetylcholinesterase dihydroisoxazoles from (R)-limonene

We report herein the convenient procedures for the efficient and easy synthesis, and the antimicrobial and the anti-acetylcholinesterase evaluation of two new series of (R)-limonene derivatives. A substantial modification aimed at targeting to discover novel structures with a better antimicrobial and anti-acetylcholinesterase (anti-AChE) activities. The condensation of (R)-limonene (1) with various arylnitrile oxides led, via the 1,3-dipolar cycloaddition reaction, conducted with complete region-specificity, to a series of new limonene-dihydroisoxazoles, 2a-h. On the other hand, N-alkylation of the previously prepared limonene-lactam derivative (3) yielded the corresponding dipolarophile (4), which affords by condensation with arylnitrile oxides the expected new dihydroisoxazoles, 5a-h. The target compounds were completely characterized by 1H NMR, 13C NMR and MS. All the synthesized heterocyclic compounds were tested for their antimicrobial and anti-acetylcholinesterase activities. The dihydroisoxazoles 2a (IZ = 13.25 mm, cc = 1 mg/mL) and 5b (IZ = 13.75 mm, cc = 1 mg/mL) exhibited the highest antifungal activity. The greatest anti-acetylcolinesterase activity was exhibited by 2f (IC50 = 82±3 µg/mL) and by 5a (IC50 = 99±1 µg/mL)

Anti-inflammatory and analgesic activities with gastroprotective effect of semi-purified fractions and isolation of pure compounds from Mediterranean gorgonian Eunicella singularis.

Abstract Objective To explore anti-inflammatory activities of organic extract and its semi-purified fractions (ethanol, acetone, methanol/dichloromethane) from the Mediterranean gorgonian Eunicella singularis. Methods The anti-inflammatory and analgesic activities were evaluated, using the carrageenan-induced rat paw edema model and the acetic acid writhing test in mice. The gastroprotective activity was determined using HCl/EtOH induced gastric ulcers in rats. The purification and structure elucidation of compound(s) from the more effective fraction were determined by chromatographic and spectroscopic methods and in comparison with data reported in the literature. Results The fraction F–EtOH showed an important anti-inflammatory activity associated with significant analgesic and gastroprotective properties. The purification and structure elucidation of compound(s) from this fraction lead to the identification of one diterpenoid and four sterols. Conclusions These results suggested that components from the active fraction can be used to treat various anti-inflammatory diseases

Synthesis of new antifungal 1,2,4-bis-oxadiazolines using cycloaddition reaction of nitrile oxide with bis-Schiff base

922-928A series of arylaldehydes and acetophenone when treated with 1,2-ethanediamine afford the bis-Schiff bases <span style="mso-ansi-language: DE" lang="DE">N,N’-bis(arylidene)-ethane-1,2-diamines 1-8, N,N’-bis(arylmethylene)-ethane-1,2-diamines 9-10 and the N,N’-bis(1-phenylethylidene)-ethane-1,2-diamine 11. The bis-imines 1-11<span style="mso-ansi-language:EN-US; mso-fareast-language:FR" lang="EN-US"> on regiospecific 1,3-dipolar cycloaddition with [(4-chlorophenyl)methyldyne]azans oxide, prepared in situ, afford the expected new 1,2,4-bis-oxadiazolines 12-22. The target molecules have been identified on the basis of satisfactory analytical results and <span style="mso-fareast-font-family:AdvEPSTIM; mso-ansi-language:EN-US" lang="EN-US">characterized by spectroscopic means (1H NMR, 13C NMR, UV, IR, HRMS and elemental analyses). All the previously unknown compounds 12-22 have been screened for their antifungal activity towards Trichoderma harzianum, <i style="mso-bidi-font-style: normal">Botrytis cinerea, Fusarium sambucinum and Penicillium sp. using the disc diffusion<span style="mso-fareast-font-family: AdvGulliv-R;mso-ansi-language:EN-US" lang="EN-US"> <span style="mso-ansi-language: EN-US" lang="EN-US">method. Applied at two concentrations, some of these bis-oxadiazolines exhibit an interesting inhibitory effect against the fungi tested. It is found that compounds, possessing an NO2 group on their aromatic ring, exhibit variable antifungal activity against B. cinerea depending on NO2 position. In fact, the inhibitory activity has been found to be increased when the NO2 group is situated in the meta position. </span

A regioselective 1,3-dipolar cycloaddition for the synthesis of novel spiro-chromene thiadiazole derivatives

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Synthesis of Novel Fused Coumarine and naphtho[2,1-b]pyrano[3,2- e][1,2,4] triazolo[1,5-c]pyrimidine Derivatives

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