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Satisfactory Yields (satisfactory + yield)
Selected AbstractsEfficient synthesis of polyoxygenated flavones from naturally occurring flavanonesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2007Paolo Bovicelli Flavonoids are constituents of the human diet (they are present in many beverages and food), and in organisms they are responsible for several biological functions, including that of antioxidant. Because of the increasing interest in these molecules, methods for their synthesis and structural modification are of great importance; studies on the biological activities of many of these compounds are insufficient because of their scarcity and/or high cost. We have developed an expeditious synthesis of polyoxygenated flavones, starting from available and inexpensive flavanones, using a bromination-methoxylation procedure. A series of flavonoids that are not otherwise accessible can be prepared using this method. As an example, 3,-demethoxysudachitin, a limited flavone possessing antimicrobial activity against methicillin-resistant Staphylococcus aureus and Helicobacter pylori and acting as a 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenger, was prepared in fairly satisfactory yield. [source] Synthesis of 3-(Tosylalkyl)indazoles and their Desulfonylation Reactions , A New Entry to 3-Substituted Indazoles by an Unprecedented Friedel,Crafts ProcessEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2009Silvia Campetella Abstract Reaction of indazoles with aldehydes in the presence of p -toluenesulfinic acid affords the corresponding sulfonyl indazoles in satisfactory yields. The reported Friedel,Crafts process is rather unusual on indazoles because of the reduced electronic density of the heterocycle. The obtained sulfonyl indazoles can be desulfonylated under reductive conditions, finally leading to 3-alkylated indazoles.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] A new convenient way to synthesize 1-hydroxyphosphonates from heterocyclic aldehydes and ketones under microwave irradiationHETEROATOM CHEMISTRY, Issue 4 2007Dexin Feng A simple and efficient method has been developed for the synthesis of 1-hydroxyphosphonates from heterocyclic aldehydes and ketones under solvent-free conditions using microwave irradiation. Various phosphites have been used to find the influence of steric exclusion on the reaction. The products are readily obtained in satisfactory yields, on the solid support of MgO. The reactions are also induced by oil-heat, and we find that the condition of microwave is better than oil-heat with respect to reaction times and product yields. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:347,353, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20304 [source] Zinc-Salen-Catalyzed Asymmetric Alkynylation of Alkyl AcylsilanesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Feng-Quan Li Abstract Optically active tertiary propargylic alcohols are useful and versatile building blocks in organic synthesis, and their direct access by enantioselective addition of alkyne nucleophiles to ketones has achieved significant progress over the last ten years. In view of the potential applications of acylsilanes as useful synthetic equivalents of aldehydes, we described a general catalytic enantioselective addition of terminal alkynes to alkyl acylsilanes. After reaction optimization involving variation of solvent, temperature, catalyst ratio and various catalysts screen, the in situ generated Zn-salen complex was chosen as catalyst. With hexane as solvent, the silylated tertiary propargylic alcohols were obtained in satisfactory yields and ees for both aliphatic and aromatic alkynes. [source] Efficient synthesis of benzothieno[3,2- d]-1,2,4-triazolo [1,5- a]pyrimidin-5(1H)-ones via a tandem aza-Wittig/heterocumulene-mediated annulationJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2009Sheng-Zhen Xu The carbodiimides 2, obtained from reactions of iminophosphorane 1 with isocyanates, reacted with hydrazine to give selectively 3-amino-2-arylaminobenzothieno[3,2- d]pyrimidin-4(3H)-ones 4. Reactions of 4 with triphenylphosphine, hexachloroethane, and Et3N produced iminophosphoranes 5. A tandem aza-Wittig reaction of iminophosphorane 5 with isocyanate, acyl chloride generated benzothieno[3,2- d]-1,2,4-triazolo[1,5- a]pyrimidin-5(1H)-ones 7 and 9 in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated. J. Heterocyclic Chem., (2009). [source] Synthesis, light emission, and photovoltaic properties of perylene-containing polyacetylenesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2008Jianli Hua Abstract Perylene (Py)-containing polyacetylenes with different skeleton structures [HCC(C6H4)CO2Py]n (P1), [HCC(CH2)8CO2Py]n (P2), and {[(C6H5) CC(CH2)9NH2]co[(C6H5)CC(CH2)9Py]}n (P3) are synthesized in satisfactory yields by Rh-catalyzed polymerization (for P1 and P2) and polymer reaction (for P3). All the polymers are soluble and possess high molecular weights (Mw up to 2.8 × 105). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 ,A/cm2. The external quantum efficiency is sensitive to the polymer structure, with P3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025,2037, 2008 [source] Synthesis of liquid crystalline poly(1-pentyne)s and fabrication of polyacetylene,perovskite hybridsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2006Jianli Hua Abstract Poly(1-pentyne)s containing biphenyl and phthalimido pendant groups with different spacer lengths {P1(m); [HCC(CH2)3OBiphOCO(CH2)mN(CO)2C6H4]n, Biph4,4,biphenylyl; m = 7, 10} are synthesized in satisfactory yields by WCl6 -Ph4Sn catalyst in toluene at elevated temperatures. The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, DSC, POM, and XRD analyses. Both of the polymers are thermally stable (Td , 300 °C) and exhibit nematicity at high temperatures. Their phthalimido groups are converted into amino groups by hydrolysis, which can, after acidification, complex with lead(II) bromide to furnish polyacetylene,perovskite hybrids in high yields. The organic components contribute good solubility to the hybrids, while the perovskite framework induces the polyacetylene chains to align within the inorganic sheets. The hybrids emit a strong UV light of 374 nm upon photoexcitation, whose quantum yield increases with an increase in the spacer length. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3538,3550, 2006 [source] | ||||||||||