Microwave‐assisted Chemical Reactions

Microwave (MW) radiation has been used in chemical analysis and chemical synthesis. MW heating under controlled conditions offers distinct advantages over conventional heating. The reactions are carried out in environmentally clean and safe solvents and in many cases, reactions can be carried out under solvent‐free conditions. This method of synthesis has grown rapidly and found its use in various sectors. This paper reviews some of the reactions that have been accelerated with higher yields under MW irradiation. The application of MW‐assisted synthesis in the medicinal and pharmaceutical industries will be emphasized.     

The Reactions of Sydnone Compounds

The duality in electronic effect of sydnone ring and the effect of delocalization of 4-substitutedgroup to sydnone ring are investigated by the nitration of 3-benzyl-4-phenylsydnone and 4-formyl-3-arylsydnones. Sydnones are typical mesoionic compounds and their chemical, physical and biological properties     

Preparation and Reactions of Octasilsesquioxanes

Because of the length scales involved, nanocomposite materials incorporate extensive interfacial interactions that can result in non-linear changes in the composite property. Chemists often start from polymerizable inorganic and organic constituents in the molecule to build organic/inorganic hybrids that combine advantageous properties of disparate components. Silsesquioxanes (RSiO1.5)n, derived from e.g. RSiCl3 or RSi(OEt)3 by hydrolysis/condensation in a sol-gel process, are a class of s…     

Boolean Logic Gates Realized with Enzyme-catalyzed Reactions – Unusual Look at Usual Chemical Reactions

Research in the area of molecular computing systems, in the general framework of unconventional computing, has received high attention and resulted in rapid progress in formulating signal-controlled switchable molecules capable to perform Boolean logic operations and basic arithmetic functions. Extension of this research to biomolecular systems allowed sophisticated computational functions much easier than using synthetic molecular and supramolecular species. The advantage of biomolecular systems comparing with synthetic molecular systems is in their complementarity and compatibility allowing easy assembling multi-component systems from various biomolecules, thus increasing their functional complexity. While DNA-based computing systems are promising faster computing than Si-based electronics, at least for solving some combinatorial problems, due to massive parallel operation, enzyme-based logic systems are less promising for computational applications in their narrow definition. However, they offer novel biosensing and bioactuation features operating in binary Yes/No format. The present review article overviews different kinds of enzyme logic gates exemplified with specific enzymatic reactions/cascades. Motivation for this research and its possible applications are discussed. The review will be helpful to researchers working in this specific area to see the comprehensive collection of logic operations performed by the enzyme reactions. The newcomers to the reviewed area will benefit from the example systems representing various logic functions systematically.     

Reactions of α-nitroacrylates with thiophenols

Reactions of α-nitroacrylates with aromatic thiols like 4-methyl- and 4-chlorothiophenols afford a series of new 3-arylsulfanyl-2-nitropropanoates. The latter were isolated as diastereomerically pure substances or mixtures of two diastereomers. Structures of the obtained S-adducts were confirmed by IR, ¹H and ¹³C-{¹H} NMR spectroscopy using HMQC and HMBC experiments.     

The Chemical Reactions of 11-Hydroxycephalotaxine

1l-HydroxycephalotaxinelisoneofthethreeC,,-oxygenatedalkaloidsisolatedfromthegenusCePhalotaxus.Onlyafewreportsonthechemicaland,biologicalactivityandderivationsoflwerefoundl-3.Someofthechemicalreactionsofll-hydroxy-cephalotaxinel,whichwereencounteredduringthederivationoflandtherelatedcompoundsweredescribedinthispaPeLAcetylationoflwithlessthantwomolarofaceticanhydrideformedtWomonoacetateA,(C,-acetate)andB,(C,,-acetate)infavorofC,,acetylationduetothestericdifference(AandBstridthosecomPOunds…     

Oxidative Cross-Coupling Reactions between Two Nucleophiles

What is the most favorite and original chemistry developed in your research group?Oxidative Cross-Coupling-The chemistry between two"nucleophiles".How do you get into this specific field?Could you please share some experiences with our readers?My first contact with palladium chemistry was the halopalladation of acetylene in 1998.Then I worked on palladium enolate and found it could initiate a transmetalation reaction.Until 2006,I found that desyl chloride(a halogenated hydrocarbon)showed different reactivity with orga no metallic reagents due to the halophilic and oxyphilic properties,thus we achieved the cross-coupling between two orga no metallic reagents.     

Reactions of α-halonitrosoalkanes with resorcinol

-Halonitrosoalkanes react with resorcinol as nitrosylating agents to form 3-hydroxy-N-(2,4-dihydroxyphenyl)-1,4-quinone imine.Translated fromIzvestiya Akademioi Nauk. Seriya Khimicheskaya, No. 3, pp.773–774, March, 1996.     

Catalysis of Carbon–Gas Reactions

The characteristic features on the catalysis of carbon–gas reactions has been studied by combining various techniques such as transient kinetics, temperature-programmed desorption and others. Some of recent achievements are presented to comprehend the state of the art. Many industrial processes associated with catalytic carbon–gas reactions are then discussed in relation to the fundamental chemistry of catalysis.     

Acceleration of Organic Reactions Using Microwave

The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted direct amide formation from carboxylic acid and amine, the hydrolysis of biopolymers, and nucleophilic aromatic substitution reaction. The reactions carried out under microwave irradiation, in general, …     

Reactions of magnesium formate on supports

Thermal decomposition of supported magnesium formate has been studied by gas chro-matography.The reaction paths of decomposition of supported magnesium formate depend on thenature of the supports.For Mg(HCO_2)_2/HZSM-5,the zeolite behaves as a dehydration catalyst togive CO and H_2O at lower temperatures;when the zeolite is modified by phosphorus,the methanationreaction will be partly restrained.In the case of Mg(HCO_2)_2/AC,strong adsorption of CO_2 leadsto the formation of the shoulder peak of CO_2 at higher temperatures,however,CH_4 disappears aftermodified by phosphorus.For Mg(HCO_2)_2/Al_2O_3,the dehydrogenation of HCO_2~- takes place on thesurface of Al_2O_3.The decomposition of Mg(HCO_2)_2 on SiO_2 in hydrogen yields two peaks of COand only one appears after modified by phosphorus.When Mg(HCO_2)_2 decomposes on MgO,the firstpeak of CO_2 arises from the reaction of surface Mg~(2+) with HCO_2~- from dissociated Mg(HCO_2)_2.     

Some Reactions of α-Allenic Boronates

α-Allenic boronates, readily available in high yield from gem-borazirconcene alkanes, react with iodine to give diiodo adducts that when treated with sodium acetate provide 2-iodo-1,3-butadienes. Alternatively, hydrozirconation of the α-allenic boronates followed by treatment with D₂O occurs regioselectively to place deuterium in the allylic position.     

Factors Influencing Sulfinatodehalogenation Reactions of Perhalocarbons

The study on the factors influencing sulfinatodehalogenation of perfluorohexyl chloride plus octene-1 by using Na2S2O4/NaHCO3 discovered that among the various solvents tested (e.g. Me2SO, NMP, DMAc, CH3CN,CH3CN/H2O) at different temperatures, Me2SO was found to be the most suitable solvent and the conversion of the chloride was very dependent on the reaction temperature. When Me2SO was used in the reaction of perfluoroalkyl iodides, the reaction temperature could be decreased by 20℃ as compared with that carried out in CH3CN/H2O to reach the comparable yields.     

Reactions of α-Sulfenyl-N-anions at the Nitrogen Atom. Reactions of N-Substituted Arenesulfenamide Sodium Salts with Isocyanates

N-Arylsulfonylarenesulfenamide sodium salts react with isocyanates in acetone to give N-arylsul- fonyl-N-arylsulfenyl-N'-substituted urea sodium salts which are converted into the corresponding ureas by the action of mineral acids.     

Transition Metal Catalyzed Enantioselective Borylative Cyclization Reactions

Due to the significance of corresponding products,enantioselective borylative cyclization reactions have been studied intensively in recent years.Many groups have developed efficient methods to transform unsaturated system into asymmetric cyclic organoboron compounds with the ring-size range from three-membered to six-membered in general.Notably,in some cases,fused rings which contain more than two contiguous chiral centers could be obtained by this kind of strategies.This review summarized and reviewed the recent advances in this field and classified these work according to the species of metal catalysts.     

Some New Highselective Reactions of Organoboron Compounds

It was found for the first time that carbon dioxide under pressure could carboxylate lithium tri-alkylalkynylborate. In the reaction, carbon dioxide attackedd the β-carbon of the alkynyl group and analkyl group migrated from boron to the α-carbon of the alkynyl group, followed by protonation, giv-     

Reactions of cyanofurazans with β-dicarbonyl compounds

In the presence of nickel acetylacetonate, -dicarbonyl compounds readily add at the nitrile group of 4-R-3-cyanofurazans to form enaminofurazans. The adducts obtained from 4-amino-3-cyanofurazan underwent intramolecular cyclization on heating with AcOH in EtOH to give furazano[3,4-b]pyridine derivatives in high yields.     

Reactions of α-aminoazoles with diethyl benzylidenemalonate

Cyclocondensations of diethyl benzylidenemalonate with 3-amino-5-methylpyrazole, 3,5-diamino-1,2,4-triazole, 3,4,5-triamino-1,2,4-triazole, and 2-amino-benzimidazole in alcohols take a single route and lead to the formation of functionally substituted partially hydrogenated pyrazolo-, triazolo[1,5-a]-pyrimidin-5-ones and pyrimido[1,2-a]benzimidazol-2-one respectively. From reaction mixtures involving 3-amino-1,2,4-triazole and its 5-methylsulfanyl analog in methanol the intermediate products of heterocyclization were isolated forming as a result of alkylation with the β-carbon of the unsaturated ester the endocyclic nucleophilic sites of aminoazoles. The structure of one among the products obtained, diethyl(3-amino-5-methylsulfanyl-1,2,4-triazol-2-yl)benzylmalonate was proved by X-ray crystallography. In DMF the same reagents yielded mixtures of partially hydrogenated triazolo[1,5-a]pyrimidin-5-ones.     

Theoretical Study on Dehydrogenation Reactions of Silanol

The pathway of dehydrogenation reaction of silanol SiH3OH is investigated by ab initio Mo calculations using RHF/-31G basis set. The geometries of reactant, transition states and products are optimized on the singlet potential energy surface of the ground state. The activation energies, reaction heats, statistical A factor and activation entropies are calculated. The vibrational analysis of the reactant and the transition states is made. The reaction crgodography along the intrinsic reaction coordinate (IRC) are performed to examine the reaction mechanism.