Chromene is considered a fused pyran ring with a benzene ring, which is found in many plants and is part of many important compounds such as anthocyanidins, anthocyanins, catechins, and flavanones. These compounds are included under the headings "flavonoids" and "iso-flavonoids." These compounds are well known as bioactive molecules with wide medicinal uses. According to these pharmacokinetic characteristics, many researchers are giving more attention to this type of compound and its derivatives. Many chromene derivatives have been synthesized to study their biological effects for the treatment of many diseases. Furthermore, the researcher displayed wide interest in finding new methods for synthesizing chromene derivatives. These methods depend on utilizing a new catalyst to increase the yield of this reaction or reduce the time of the reaction. On the other hand, new methods were found by using a new reactant and a new substrate. This review will present the most recent important methods for the synthesis of chromene derivatives as well as an examination of their biological activity.
The area of character recognition has received a considerable attention by researchers all over the world during the last three decades. However, this research explores best sets of feature extraction techniques and studies the accuracy of well-known classifiers for Arabic numeral using the Statistical styles in two methods and making comparison study between them. First method Linear Discriminant function that is yield results with accuracy as high as 90% of original grouped cases correctly classified. In the second method, we proposed algorithm, The results show the efficiency of the proposed algorithms, where it is found to achieve recognition accuracy of 92.9% and 91.4%. This is providing efficiency more than the first method.
This paper presents a study for the influence of magnetohydrodynamic (MHD) on the oscillating flows of fractional Burgers’ fluid. The fractional calculus approach in the constitutive relationship model is introduced and a fractional Burgers’ model is built. The exact solution of the oscillating motions of a fractional Burgers’ fluid due to cosine and sine oscillations of an infinite flat plate are established with the help of integral transforms (Fourier sine and Laplace transforms). The expressions for the velocity field and the resulting shear stress that have been obtained, presented under integral and series form in terms of the generalized Mittag-Leffler function, satisfy all imposed initial and boundary conditions. Finall
... Show MoreIn this study, the flavonoid and alkaloid content in the alcoholic extract of the shoots and flowers were identified in four species of the tribe Apieae / Apiacese : Ammi majus, Ammi visgana, Anethum graveolens and Foeniculum vulgaris, and the flavonoids that were detected are (Apigenin, Coumarin, Kaempferol and Quercetin). The species Foeniculum vulgaris has recorded the highest concentration of total flavonoid content (Shoots and Flowers) among the studied species, reaching 4139.2 µg / ml. The total alkaloids are estimated for these species, and the Foeniculum vulgaris has recorded the highest concentration of the total alkaloid content as well.
The thermal properties of four nematogenic Schiff’s bases, n-butyl-to-n-heptyl of bis (4-n-alkyloxybenzylidine)-2,3,5.6- tetramethyl-1, 4-phenylenediamine, have been studied. The transition temperatures and enthalpies of transition were examined by differential scanning calorimeter (DSC). Several correlations were carried out; those included the relations between transition temperatures, enthalpies and entropies of transition with increasing the
number of carbon atoms in the terminal alkyl chains. In addition, new regular relations were found between the ratio of the enthalpies and of the entropies, for noematic-isotropic transition and crystal-isotropic transition ( ΔΗÎ-i/AHC-I, ΔS
(4R)-2, 3-(2`-chloro-2`- carboxyl)-1, 3-dioxolano-4- (2- dimethyl –dioxolane -yl) ascorbic acid (HL), a derivative of L-ascorbic acid was prepared by the reaction of 5,6-O-isopropylidene–L-ascorbic acid with trichloroacetic acid in alkaline medium. Seven new metal ion complexes of this ligand (HL) were prepared through its direct reaction with the chlorides of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) ions respectively. The new ligand and its ion metal complexes were characterized applying elemental analyses,1H and 13C NMR, IR as well as UV-Visible spectra. Spectroscopic data showed that the ligand (C11H11O8Cl) was coordinated to the metal ions through the two oxygen atoms of the carboxyl group as abidentate ligan
... Show MoreAPDBN Rashid, Review of International Geographical Education Online (RIGEO), 2021
This paper aims to study the chemical degradation of Brilliant Green in water via photo-Fenton (H2O2/Fe2+/UV) and Fenton (H2O2/Fe2+) reaction. Fe- B nano particles are applied as incrustation in the inner wall surface of reactor. The data form X- Ray diffraction (XRD) analysis that Fe- B nanocomposite catalyst consist mainly of SiO2 (quartz) and Fe2O3 (hematite) crystallites. B.G dye degradation is estimated to discover the catalytic action of Fe- B synthesized surface in the presence of UVC light and hydrogen peroxide. B.G dye solution with 10 ppm primary concentration is reduced by 99.9% under the later parameter 2ml H2O2, pH= 7, temperature =25°C within 10 min. It is clear that pH of the solution affects the photo- catalytic degradation
... Show MoreMiscarriage is one of the fundamental complications occurring in pregnant women. Many fastidious and uncultivated bacterial species are related to miscarriage and have a significant role in the infection. The association between inverse pregnancy outcomes and infections of abnormal bacteria has been rarely investigated. Therefore, this study aimed to determine Leptotrichia amnionii and Atopobium vaginae as a risk factor for miscarriage states. A total of 80 cervical swabs and blood samples were obtained from females (34 non-pregnant with recurrent spontaneous miscarriage, 11 pregnant who had previous miscarriage, and 35 without miscarriage as control) who were referred to a hospital in Baghdad city. The relationship bet
... Show MoreThe corrosion inhibiting properties of the new furan derivative 5-(furan-2-ylmethylsulfonyl-4-phenyl-2,4- dihydro [1,2,4] triazole-3-thione in acidic solution (1.0 M HCl) were explored utilizing electrochemical, surface morphology (AFM), and quantum chemical calculations approaches. The novel furan derivative 5-(furan-2-ylmethylsulfonyl-4-phenyl-2,4- dihydro [1,2,4] triazole-3-thione shows with an inhibitory efficiency value of 99.4 percent at 150 ppm, carbon steel corrosion in acidic medium is effectively inhibited, according to the results. The influence of temperature on corrosion prevention was studied using adsorption parameters and activation thermodynamics. The novel furan derivative creates a protective layer over the metallic surfa
... Show MoreIn this work, the ligand was obtained from the reaction of diazonium salt of naphthyl amine with 1-amino-2-naphtol-4-sulfonic acid. The bidentate ligand type (NO) donar atoms was reacted with 1,10-phenanthroline and matel salt in a 1:1:1 mole ratio to give the complexes, using NaOH as a base. Physical-chemical teqnichas were used to characteriz the prepared compounds FT-IR,U.V-Vis, fluorescence and 1HNMR spectroscopy, atomic absorption , chloride content along with conductivity and melting point measurements .Finally, thermal analysis was used to confirm the presence of coordination H2O molecule in the complexes structure. According to memtioned characterization methods, the general formula proposed for CoII ZnII, CdII and Hg
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