Heteropolyacid-catalyzed Reaction of Epoxides with Ketones： Efficient Synthesis of 1,3-Dioxolane Derivatives

An efficient method for the preparation of 1,3-dioxolanes via the coupling of epoxides with ketones catalyzed by heteropolyacids at ambient temperature has been described.     

FeCl3-Mediated Reaction of 1,4-Dilithio-1,3-dienes with Alkynes Affording Benzene Derivatives

Unactivated alkynes reacted with 1,4-dilithio-1,3-diene derivatives in the presence of FeCl3 affording substituted benzene derivatives via a formal[4 2] cycloaddition.     

Facile Synthesis of 1, 2-Diazepine Derivatives under Microwave Irradiation

An efficient and convenient synthesis of 3, 5, 7-triaryl-4H-1, 2-diazepine from 2, 4,6-triarylpyrylium salts and hydrazine in water under microwave irradiation is reported. The same reaction can be conducted using 2, 4, 6-triarylthiopyrylium salts and hydrazine.     

Investigation of Isomerization of 2—Seleno—1,3,2—diazaphospholidine Derivatives

For the first time the isomerization of 1,3,2-diazaphospholidine-2-sclenide dervatives in refluxing benzene in the presence of trace water was observed. The structures of isomerized products were determined by IR, ^1H NMR,^31P NMR, elemental analysis and X-ray crystallography. The mechanism of isomerization was also proposed.     

Synthesis of 5—Deoxy—5—Acyloxyiminoavermection B1 Derivatives

Four 5-deoxy-5-acyloxyiminoavermectin B1 derivatives 4a-d were synthesized via three steps from avermenction B1 and their biological activities were tested against Heliothis armigera, Laphygma exigua and Musca domestica.     

通过α—重氮—β—二酮与醛酮的环加成反应合成4H—1,3—二恶环已—5—烯 …

研究了α-重氮-β-二酮与各类羰基化合物的环加成反应,合成了一系列4H-1,3-二噁环己-5-烯-4-酮衍生物.     

Synthesis and Insulin—sensitizing Activity of a Series of 2—Benzyl—1,3—dicarbonyl Derivatives

A series of 2-benzyl-1,3-dicabonyl derivatives was synthesized.Their insulin-sensitizing activity was evaluated in 3T3-L1 preadipocyte cells.Compounds3,26 and 27 were found to possess strong insulin-sensitizing activity in vitro and were selected for further hypoglycemic evaluation in vivo.     

Synthesis of 4—Aryl—3,4—dihydropyrimidinones Using Microwaveassisted Solventless Biginelli Reaction

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不需加催化剂在纯水相介质中进行芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应

在纯水相中,不另加任何催化剂可以十分方便、有效地通过芳香醛与5,5-二甲基-1,3-环己二酮间的缩合反应合成氧杂葸二酮类衍生物.该反应只需在热水中搅拌下即可有效进行.而且这种方法具有明显的环境友好、高产率和操作过程简便的优点.     

对苯二甲醛或间苯二甲醛与5，5-二甲基-1，3-环己二酮的反应：含有双4（日）-吡喃、1，4-二氢吡啶结构单元的杂环化合物的合成

用对苯二甲醛或间苯二甲醛与5，5-二甲基-1，3-环己二酮反应，在不同条件下得到了含有双4(H）-吡喃、1，4_二氢吡啶结构单元的双一氧杂蒽衍生物、双-吖啶衍生物、以及双-AL羟基吖啶衍生物．     

对苯二甲醛或间苯二甲醛与5,5-二甲基-1,3-环己二酮的反应:含有双4(H)-吡喃、1,4-二氢吡啶结构单元的杂环化合物的合成

用对苯二甲醛或间苯二甲醛与5,5-二甲基-1,3-环己二酮反应,在不同条件下得到了含有双4(H)-吡喃、1,4-二氢吡啶结构单元的双-氧杂蒽衍生物、双-吖啶衍生物、以及双-N-羟基吖啶衍生物.     

功能离子液体水相催化芳醛与5,5-二甲基-1,3-环己二酮的反应

以N,N,N′,N′-四甲基乙二胺、1,3-丙磺酸内酯为原料,经酸化合成了功能化离子液体N,N,N′,N′-四甲基-N,N′-二磺丙基二硫酸氢盐(TSIL). TSIL离子液体兼具Brnsted 酸性官能团和季铵盐相转移催化剂的结构,能够实现水相中芳醛与5,5-二甲基-1,3-环己二酮反应,得到氢化氧杂蒽衍生物. 结果表明,合成的TSIL具有较高的催化活性,在水相中于100 ℃下回流2～3 h即可完成反应,产率可达80%～93%. 反应生成的取代氢化氧杂蒽与离子液体的水溶液不相溶,通过简单的过滤可实现产物与催化体系的分离,简化了分离过程,方法操作简便、环境友好、催化剂可回收并重复使用.     

Reaction of organomagnesium compounds with 2-bromo-1,3-cyclohexanedione

Summary Reaction of methylmagnesium iodide and of ethylmagnesium bromide with 2-bromo-1,3-cyclohexanedione (IV) gave 2-bromo-3-methyl- and 2-bromo-3-ethyl-2-cyclohexen-1-ones (X) and (XI)-, respectively. When these products were vacuum-distilled, they were converted into the m-substituted phenols (XII) and (XIII).Treatment of the bromocyclohexenones (X) and (XI) with dilute alkali gave the cyclic a-diketones (XVI) and (XVII).     

Spectrophotometric determination of selenium(IV) with 5,5-dimethyl-1,3-cyclohexanedione

5,5-Dimethyl-1,3-cyclohexanedione (dimedone) reacts in acid aqueous solution with selenium(IV) to give a benzoxaselenol which has an absorption maximum at 313 nm with a molar absorptivity of 4.00 x 10(3) l.mole(-1).cm(-1). The compound is extractable into chloroform, to give a solution with an absorption maximum at 300 nm with a molar absorptivity of 3.77 x 10(3) l.mole(-1).cm(-1). The calibration graph is linear up to 30 ppm selenium, with a detection limit of 0.1 ppm in the final solutions. Of the various other ions tested, only iron(III) interferes at all concentrations but the addition of 1000 ppm fluoride will mask 50 ppm Fe(3+). The method has good reproducibility, with a relative standard deviation of 1.0% for pure solutions. The method has been applied to the analysis of fire-refined copper.     

Efficient,Solvent-Free,Microwave-Enhanced Condensation of 5,5-Dimethyl-1,3-cyclohexanedione with Aldehydes and Imines Using LiBr as Inexpensive,Mild Catalyst

Efficient, solvent-free, microwave-enhanced condensation of 5,5-dimethyl-1,3-cyclohexanedione with aldehydes using LiBr as catalyst affords xanthenediones. Imines gave only bis-5,5-dimethyl-1,3-cyclohexanediones at high power; a slightly longer period gave xanthenediones. In both types of reactions, the products are obtained in very good to excellent yields. The present protocol is inexpensive and ecofriendly.