Total Synthesis of Kaempferol and Methylated Kaempferol Derivatives

Kaempferol ( 1 ), a natural product from various plants, was synthesized in which the longest linear sequence is only seven steps in over all yields of 47% from commercially avail able 1,3,5‐trimethoxybenzene (10). The methylated kaempferols 2–5 were also pre pared by use of this concise synthetic methodology. The key transformations in this synthesis involved the I₂ oxidative‐promoting‐cyclization and DDO oxidative hydroxylation. Several strategies to achieve 1 are provided.     

Synthesis of the Substituted 3‐Cyclobutene‐1,2‐diones

A convenient synthesis of the novel squaric acid derivatives is reported. Unsymmetrically substituted 3,4‐diamino‐3‐cyclobutene‐1,2‐diones and 3‐amino‐4‐hydroxy‐3‐cyclobutene‐1,2‐diones were prepared by interaction of diethyl squarate with different nucleophilic reagents such as alkali, primary and secondary amines and amino acids. Substituted 3‐amino‐4‐aryl‐3‐cyclobutene‐1,2‐diones were synthesized by interaction of squaryl dichloride with different arenes followed by arylsquarylation of amines. Efficient procedures were developed for consequent substitution of ethoxy groups in diethyl squarate and chlorine atoms in squaryl dichloride. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening.     

Synthesis of Substituted Terphenyl Derivatives

Several substituted terphenyl derivatives were prepared following two synthetic routes with five steps. Condensation of 4‐amino‐3‐bromo‐benzotrifluoride with 4‐(methylthio) phenyl boronic acid in the presence of sodium carbonate and palladium triphenylphosphine in toluene gave 4‐amino‐3‐(4‐methylthiophenyl)‐benzotrifluoride. Treatment of this compound with osmium tetroxide in the presence of 4‐methyl morpholine‐N‐oxide yielded the corresponding sulfone, which was converted into the iodo derivative using sodium nitrite. The iodo derivative thus obtained was treated first with propylmagnesium chloride and triethylborane and subsequently with hydroxylamine‐O‐sulfonic acid to furnish the target compounds.     

苯烷基取代的对苯二酚的合成

以1,4－二甲氧基苯为原料,经傅氏酰基化反应、黄鸣龙改良还原、醚键的断裂三步反应合成了3个苯烷基对苯二酚。产物的结构由元素分析、IR和^1H NMR确认。     

Syntheses of Substituted Indan 1 ones and Indenes

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Synthesis and Spectral and Electrochemical Characterization of Novel Substituted 1,4-Naphthoquinone Derivatives

The novel substituted 2,3-dichloro-1,4-naphthoquinone derivatives were synthesized from the reactions of (1) and related nucleophilles in sodium carbonate (Na₂CO₃) solution of ethanol, chloroform with Et₃N, or potassium carbonate (K₂CO₃) solution of acetonitrile. The structures of novel compounds were characterized by using microanalysis, Fourier transform–infrared, ¹H NMR, ¹³C NMR, mass spectrometry, and cyclic voltammetry (CV).

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

有机硅氨基酸衍生物的研究

本文利用含氢有机硅化合物与含双键的氨基酸酯的加成反应,合成了5种新的有机硅氨基酸衍生物。介绍了一种合成N-烷基取代氨基酸酯的新方法。对新化合物进行了元素和光谱分析鉴定。     

A One Pot Synthesis of 5-Phenyl-1,3-Dioxane-4,6-Dione Derivatives

A general procedure for synthesis of 5-phenyl-1,3-dioxane-4,6-dione derivatives is described. The synthesis involves the cycloaddition of (α-chlorocarbonyl)phenyl ketene with carbonyl compounds to generate the corresponding substituted 2-oxetanone's which is readily transformed to the final products in one step. The 1,3-dioxane-4,6-dione is a rigid cyclic structure, and can undergo easy hydrolysis.     

Synthesis of Substituted 4‐Aroyl‐1‐indanone and 5‐Aroyl‐1‐tetralone

Several substituted 4‐aroyl‐1‐indanones 2 and 5‐aroyl‐1‐tetralones 3 were prepared in good yields from 1‐indanones 1 via a series of reasonable transformations.     

Synthesis and Characterization of New Xanthene Derivatives,and Their Electrochemical Study

This work investigated the synthesis of biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride derivatives ( 3a – e and 6a – e ) with different substituted phenols via Friedel‐Crafts acylation reaction in the presence of dilute sulfuric acid. Dianhydride derivatives with 3‐N,N′‐dimethylamino phenol ( 3d and 6d ) and resorcinol ( 3e and 6e ) have been found to be highly fluorescent. The structures of all newly synthesized compounds were confirmed by the chromatographic, spectral and elemental data. Electrochemical study was done to determine to band gap energy, LUMO and HOMO levels energy. Band gap and LUMO energy levels were found to be lowest in xanthene derivatives substituted with 3‐N,N′‐dimethylamino group having value 2.24 and 4.85 eV respectively.     

Enantioselective Friedel–Crafts Alkylation of Indoles with Alkylidene Malonates Catalyzed by N,N′‐Dioxide–Scandium(III) Complexes: Asymmetric Synthesis of β‐Carbolines

An efficient catalytic asymmetric Friedel–Crafts alkylation of indoles with alkylidene malonates has been developed by using a chiral N,N′‐dioxide–Sc(OTf)₃ complex as the catalyst (see scheme). Some optically active intermediates containing the indole skeleton have been synthesized, such as indolepropionic acid, tryptamines, and β‐carbolines. The coordination between the scandium atom and the chiral N,N′‐dioxide compound has been revealed by X‐ray structure analysis.

     

Aluminium Chloride‐Catalyzed Intermolecular vs Intramolecular Friedel‐Crafts Reaction of Acrylanilides and 3‐Chloropropanamides

3‐Phenylpropionanilide ( 4a ) is obtained in a yield of 89% from acrylanilide by the treatment with AlCl₃/benzene, compared with a yield of 39% by the 1,4‐conjugate addition of phenyllithium. The formation of 4a indicated that an intermolecular Friedel‐Crafts reaction occurred, rather than the relatively more facile intramolecular ring cyclization, and provided a more efficient route than a conjugate addition of phenyllithium for the preparation of 3‐phenylpropionanilide and its derivatives. Although the methoxy group is an activator of the nucleophilic substitution, introduction of a methoxy substituent at N‐phenyl did not increase the competitive capability of the intramolecular cyclization because of AlCl₃‐catalyzed demethylation to form the ArOAlCl₂ complex which decreased the availability of the π‐electron in the N‐phenyl aromatic system.     

氯硝柳胺衍生物的合成与结构表征

由氯硝柳胺与1,2-二溴乙烷反应,得到2-(2-溴乙氧基)-5-氯-N-(2-氯-4-硝基苯基)苯甲酰胺,再与乙二醇、二乙二醇、三乙二醇分别反应,得到了三个氯硝柳胺衍生物,其结构由IR1、H NMR和高分辨质谱确证。     

取代邻羟基二苯甲酮的合成1,3,5-三甲氧基苯与对位取代苯甲酰氯的Friedel-Crafts反应

控制反应物摩尔比、反应温度和反应时间，１，３，５－三甲氧基苯与对位取代苯甲酰氯发生Ｆｒｉｅｄｅｌ－Ｃｒａｆｔｓ反应，选择性地合成了２－羟基－４，６－二甲氧基－４－Ｒ－二苯甲酮和３－（４″－Ｒ－苯甲酰基）－２－羟基－４，６－二甲氧基－４－Ｒ－二苯甲酮。反应条件温和，产率较高。化合物的结构都经元素分析、１ＨＮＭＲ和ＩＲ确定。     

Synthesis and Characterization of Chloropentaaryloxycyclotriphosphazene Derivatives

Five chloropentaaryloxycyclotriphosphazene derivatives were synthesized by the reaction of hexachlorocyclotriphosphazene with potassium phenoxide in tetrahydrofuran. A satisfactory yield could be obtained when a 5.1 : 1(KOC ₆ H ₄ R : P ₃ N ₃ Cl ₆ ) molar ratio was used. The new compounds were characterized by IR, ¹H NMR, ³¹P NMR, ¹³C NMR, and ESI-MS, and for two of them by HR-MS.     

Synthesis and Bioactivity of Substituted Benzoylguanidine Derivatives as Potent Na+/H+ Exchanger Inhibitors

A novel series of substituted benzoylguanidine derivatives were designed and synthesized in order to evaluate their NHE1 inhibitory activity. Most of them were found to inhibit NHE1‐mediated platelet swelling in a concentration‐dependent manner, and eight compounds showed more potent NHE1 inhibitory activity than Cariporide. Compound 6f with an IC₅₀ value of 1.08×10^?10 mol·L^?1, was 39 times more potent than lead compound CPU‐X‐050420 in vitro tests.     

New Halo Compounds of Si,P, As,AND Sb Bearing a Bulky Substituted Fluorenyl Group

New halo compounds of Si, P, As, and Sb, potential precursors of doubly-bonded derivatives of these elements, have been synthesized: dichloro-and difluorosilanes 2–6 bearing a methylfluorenyl group and a second substituent of various size (Me, Ph, Mes, R₂CMe); dichlorophosphines 13 and 14, fluoro- and difluoroarsines 15 and 16 and fluorostibine 17, substituted by the diphenyl (or dimesityl) phosphinofluorenyl group. Phosphine oxide and sulfide 9 and 10 also have been prepared.