Studies on the Formation Mechanism of Silica-Sodalite in the System of Sodium Hydroxide-Silica-Ethylene Glycol

In 1985,Bibby and Dale first reported the synthesis of silica-sodalite from organic solvent such as ethylene glycol or propanol.In 1987, Van Erp and his coworkers reported the formation of crystalline aluminosilicates in organic solvents such as hexanol,glycol, glycerol, sulfolane and pyridine. Because the concepts effective in the aqueous synthesis cannot be simply applied to the nonaqueous media,the formation mechanism of zeolite in the nonaqueous system has not been investigated yet.     

Application of Microwave Heating Technique to Esterification

Introduction Although the application of microwave technique has been reported as a new type of energy source chemically, it is only in recent years that this technique has been used as the energy source for organic synthesis. In 1986, R. Gedye, et al., published the report of the benzoate synthesis from the respective reactions between benzene carboxylic acid and methanol, propanol or butanol under microwave heating and the catalysis of H_2SO_4.     

A New Approach to Ethyl 1-Aroyl/Aroylmethyl-5-methyl-3-methylthiopyrazole-4-carboxylates： High Regioselectivity in Alkylation and Acylation Reactions between N-1 and N-2 of a Pyrazole Derivative

It has been known that pyrazole ring has two main tautomeric isomers1-3as showed in Scheme1.The proton could migrate at the two nitrogen atoms of the pyrazole ring.Taylor E.C.and Purdum W.R.4first reported the synthesis of2as an isomer of2a.And so far,only a few literatures5-6have reported that this pyrazole derivative was in form2a,rather than2,therefore both acylation or alkylation reaction occurred at N-1of2a.But the regiochemistry of the N-substituted product of pyrazole has not been u…     

Homocoupling of Polyfluorovinylstannanes Mediated by a Novel Combination of CuCl/2,2''''-Dipyridyl. Stereospecific Syn-thesis of Polyfluorinated Alka-2,4-dienes

Introduction Stille reaction, which is known as the cross-coupling reaction between organostannanes and organic electro-philes, has become a widely employed synthetic tool in organic synthesis for the construction of carbon-carbon single bond,1 particularly in the synthesis of naturally occurring compounds.2 But the homocoupling reaction of vinylstannanes is still limited. Intramolecular CuCl mediated oxidative coupling of alkenyltrimethylstan-nane has been reported3 and applied to the synthe…     

A Green Synthesis of 1-Aminoalkyl Phosphonates Under Microwave Irradiation without Any Catalysts and Solvent

The synthesis of 1-aminoalkyl phosphonates has been developed during past 20 years. 1-Aminoalkyl phosphonates have received much attentions as an important substrate in the synthesis of phosphonopeptides. It is reported that 1-aminoalkyl phosphonates can be used as enzyme inhibitors, antibiotics and pharmacological agents, herbicides and haptens of catalytic antibolies. Many papers mention that synthesis of 1-aminoalkyl phosphonates is convenient by using a base or an acid as a catalyst. For example, Lewis acids such as SnCl2, SnCl4, ZnCl2, MgBr2, INCl3 or acids alumia can be used as a catalyst in this reaction. It is found that the product can be obtained from a mixture of aldehydes, amine and dithyl phosphite under microwave irradiation in yields of 80%～95%.     

Synthesis and Characterization of Multithiouracils

Alkylation of bases group of nucleic acid, thymine and uracil, has attracted great attention. In order to investigate the intermolecular interactions, [1,2] and the photoreactions[3,4] between bases group of nucleic acid, many studies were focused on the synthesis of bisbases in the formation of B-(CH2)n-B (B′) in which trimethylene was commonly used as linker. Thiouracil is an important derivative of nucleic acid bases, and it can interfere with the synthesis of thyroxine, especially in the treatment of hyperthyroidism and angina. However, to our knowledge, the synthesis of bisthiouracils, even trithiouracils, using flexible or rigid linkers has not been reported. Herein, we have synthesized eight thiouracil derivatives by nucleophilic reaction between thiouracil and varied bromides. All the compounds have been characterized by IR, 1H NMR and element analysis.     

Chemoselective Reduction of Azides to Amines Using Sm/TMSCl System in the Presence of Trace Amounts of Water

Samarium diiodide and organosamarium compounds have been widely employed as useful reagents in organic synthesis1. However, relatively few reports on the direct use of samarium metal in organic synthesis have been reported2, because the surface of samarium metal is inactive3. In order to improve the activity of samarium, some additives, such as HgCl24, NH4Cl (aq.)5, or TMSCl6 were added.The reduction of azides to the corresponding amines is an important reaction in organic synthesis7-16. A…     

碘甲烷在碳酸二甲酯直接合成中的作用

Dimethyl carbonate (DMC) is an environmentally friendly compound and a substitutive intermediate for highly toxic phosgene or dimethyl sulfate in carbonylation and methylation reactions as well as a promising octane booster. The common methods for its preparation are the oxidative carbonylation of methanol catalyzed by a variety of transition metal ions and the transesterification of ethylene carbonate or propene carbonate with methanol[1]. The direct synthesis of DMC from carbon dioxide and methanol is a challenging route in which the most abundant carbon resources and a main greenhouse gas is used as feedstock. A new method for the direct synthesis of DMC catalyzed by the methoxide of main group metal has attracted more and more attention since it was reported[2～6] . However the lower conversion of the reaction has become the main obstacle for its application. In this letter, an efficient promoter for the direct synthesis of DMC is reported.     

Solid Phase Synthesis of β-Carbolines

Much attention has been paid to carbolines in recent years, owing to the wide range of their biological activity 1. Many papers have reported the synthesis and reactivity of carbolines2,3. Generally there are two ways to synthesize carbolines. One is through the Bischler-Napieralski reaction, and the other through Pictet-Spengler reaction. In the former method, the reaction of carboxylic acids with tryptophan using PPE or POCl3 as the condensing agent give dihydro-?-carbolines, which are c…     

Studies on the Total Synthesis of Hainanolide (VII) - Analysis of the Relative Stereochemistry of key Intermediate 2

The natural product, hainanolide 1, also under the name harringtonolide2 demonstrated antitumor and antiviral activities in preliminary test. Its structure was determined by X-ray diffraction. The total synthesis of 1 was reported recently by Mander3. A different scheme of its synthesis has been studied in our laboratory4. Here the determination of the stereochemical structure of the key intermediate 2 in the synthesis was reported. HMBC and HMQC spectra identified the skeleton and H,…     

APPLICATION OF THE SULFONATE ESTER GROUP AS A LINKER FOR SOLID PHASE ORGANIC SYNTHESIS

1. INTRODUCTIONIn recent years, solid phase organic synthesis (SPOS) has been increasingly used in the synthesis of small organic molecules [1]. The rapid development of SPOS brings with it the need for expanding a variety of linkers in order to accommodate new synthesis methods[2], and especially in the case of combinatorial chemistry, to allow additional diversity elements.Recently, Rueter and coworkers reported the use of a sulfonate ester as a linker in SPOS [3,4] and the compati…     

Fe（HSO4）3： An efficient,heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyl- 14H-dibenzo[a,j]xanthenes

Fe（HSO4）3 has been used as an efficient and recyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14Hdibenzo[aj]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.     

Samarium(II) Diiodide Induced Polarity Inversion of π-Allyl Palladium Complexes: The Formation of Allylic Selenides

As a versatile one-electron transfer reducing and coupling agent, samarium diiodide has been extensively used in organic synthesis in last decade. It has been reported that electrophilic p-allyl palladium complexes could undergo polarity inversion to nucleophilic species with the aid of SmI2, and could trap some electrophiles1. It is well known that allylic selenides are rather important intermediates in organic synthesis. They have been recognized as useful synthons of allylic anion stabi…     

Solid Phase Catalytic Oxidation of Alcohols by Polymer Supported Rare Earth Catalysts

Oxidation of alcohols to the corresponding aldehydes or ketones is one of the most fundamental reactions in organic chemistry [1, . Some of the products of the oxidation exhibit an 2] important role in the organic synthesis as well as pharmaceutical synthesis. In most reactions, the lanthanide complexes show satisfied catalytic activities for some compounds. Furthermore, there has been increasing interest in the lanthanide complexes and several reports have appeared in the literature[3, 4] …     

A facile synthesis of 2,4,6-trichloroborazine from boron trichloride-dimethylsulfide complex and ammonium chloride

<正>2,4,6-Trichloroborazine has been recognized as a desirable monomer for the preparation of high-performance boron nitride fibers through polymer derived ceramics route.So a high yield and facile synthesis of 2,4,6-trichloroborazine is essential in practice. Using boron trichloride-dimethylsulfide complex((CH_3)_2S·BCl_3) and ammonium chloride(NH_4Cl) as starting materials and toluene(C_6H_5CH_3) as solvent,the synthesis of 2,4,6-trichloroborazine to give high yield is reported.     

Preparation and Reactions of Amino Acid Ester Sulfones as New Remote Asymmetrical Induced Reagents

The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed that variation of the chiral auxiliary could influence asymmetric induction. Recently, it has been reported the reaction of the aminated sulfones as a remote chiral auxiliary with α,β-unsaturated carbonyl compounds.[4] Here we would like to report the preparation of amino acid ester sulfones as new remote asymmetrical induced reagents and their reactions with α,β-unsaturated esters.     

Catalytic methane removal to mitigate its environmental effect

Large reserve of methane,in the form of natural gas and methane hydrate,has been discovered and it has been intensively used as a fuel,or as a building block for the chemical synthesis.However,severe environmental and climatic issues caused by the leakage of methane during the production,transportation and use of methane are overlooked.This offers incentives for the catalytic removal of methane.Nevertheless,due to the inert nature of methane molecules,the activation of methane via thermocatalysi...     

A Convenient Synthesis of Conjugated Acetylenic Ketones by Copper(l)-Catalyzed under Microwave Irradiation

Alkynyl ketones are useful precursors and intermediates in synthetic organic chemistry1 and has evoked considerable interest. A number of methods for the synthesis of conjugated acetylenic ketones involve the reaction a metal acetylide with an acyl chlorides or another carboxylic acid derivative have been developed 2. Recently, the synthesis of α, β-conjugated acetylenic ketones catalyzed by Pd(Ⅱ) or by copper(Ⅰ)pd(Ⅱ) reaction of 1-alkynes and acyl chlorides have been described. The acylation of terminal alkynes by acyl chlorides in the presence of catalytic amounts copper(Ⅰ) salts leading to α, β-conjugated acetylenic ketones has also been reported. However, many of these reactions suffer from lack of high pressure (17 atm), long reaction time (30 h)and require low temperatures (-78℃). Our work involves the synthesis of conjugated acetylenic ketones via the reaction of terminal alkynes with aroyl chlorides in the presence of cuprous iodide under microwave irradiation conditions.     

Polyethylene Glycol as Support and Phase Transfer Catalyst in Aqueous Palladium-catalyzed Liquid-phase Synthesis

Recently, the liquid-phase synthesis of small organic compounds has been a preferable strategy due to its combination with the advantage of solution-phase and solid-phase methods1. Among the various soluble polymers, polyethylene glycol (PEG) is the most useful as support. It has been reported that PEG bound substrates could also play the role of phase-transfer catalyst (PTC) in some reactions2. Herein we reported that palladium-catalyzed coupling reactions could be taken place smoothly…     

Studies on the synthesis of some new biflavanoids——Ⅶ.Synthesis and structures of 2,2″-biflavanones

A new approach to the synthesis of 2,2″-biflavanones by the reductive dimerization of fla-vones is reported.The products,the racemate and meso biflavanones,have been separated and theirstructures have been determined on the basis of their spectral data.The configuration of 3b has beendetermined by X-ray crystallography as well.