A CONVENIENT SYNTHESIS OF LONG-CHAIN 3-n-ALKYLTHIOPHENES AND 3-n- ALKYLFURANS

Abstract

The syntheses of 3-substituted long-chain furans and thiophenes by a Wittig reaction are described. ¹H-NMR and UV data of these compounds are reported.     

A New Method for the Synthesis of gem-Dihydroperoxides

The tungstic acid-catalyzed reaction of ketals with hydrogen peroxide provides a convenient and efficient method for preparing gem-dihydroperoxides.     

Characteristic alkaline catalyzed degradation of kotalanol, a potent α-glucosidase inhibitor isolated from Ayurvedic traditional medicine Salacia reticulata, leading to anhydroheptitols: another structural proof

Stereochemical structure of kotalanol (2), a highly potent α-glucosidase inhibitor isolated from an Ayurvedic traditional medicine Salacia reticulata, was proved by alkaline catalyzed degradation of natural kotalanol (2), in which characteristic stereospecific cyclization of the degradative side chain leading to anhydroheptitols (10 and 11) was involved.     

Accessibility measures to nodes of directed graphs using solutions for generalized cooperative games

The aim of this paper consists of constructing accessibility measures to the nodes of directed graphs using methods of Game Theory. Since digraphs without a predefined game are considered, the main part of the paper is devoted to establish conditions on cooperative games so that they can be used to measure accessibility. Games that satisfy desirable properties are called test games. Each ranking on the nodes is then obtained according to a pair formed by a test game and a solution defined on cooperative games whose utilities are given on ordered coalitions. The solutions proposed here are extensions of the wide family of semivalues to games in generalized characteristic function form.     

Two new isoflavone derivatives from the roots of an Egyptian collection of Lotus polyphyllos

Investigation of the roots of Lotus polyphyllos Clarke resulted in the isolation of two new isoflavone derivatives; 4'-O-methylerythrinin C (3) and 4'-O-methyl-2'-hydroxydihydroalpinumisoflavone (4). In addition, the three known isoflavone derivatives 4'-O-methylalpinumisoflavone (1) lupinalbin F (5), 4',7-dimethoxy-5-hydroxyisoflavone (6), and the phenylpropanoid ester tetracosyl p-coumarate (2) were also identified. The structures were determined from spectroscopic data.     

Polyadic and cylindric algebras of sentences

In this note we give an interpretation of cylindric algebras as algebras of sentences (rather than formulas) of first order logic. We show that the isomorphism types of such algebras of sentences coincide with the class of neat reducts of cylindric algebras. Also we show how this interpretation sheds light on some recent results. This is done by likening Henkin's Neat Embedding Theorem to his celebrated completeness proof. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

新疆腺点金丝桃中总黄酮的提取及含量测定

利用紫外分光光度法测定腺点金丝桃中总黄酮的含量,根据黄酮的不同提取方法:1、醇提法.2、碱提酸沉法.3醇粗提后碱提酸沉法[1].确定了提取总黄酮的最佳方法,得到了满意的结果.     

Iron-Containing Adsorbents in Great Nile Sediments

Hyperfine Interactions - A sample from the Great Nile (near Khartoum) has been investigated by Mössbauer spectroscopy, infrared spectroscopy, analytical electron transmission microscopy, and...