Home About us Contact
|
Home About us Contact | ||
|
|
||
Situ Generation (situ + generation)
Selected AbstractsMu-35: A Fluorogallophosphate Obtained by In Situ Generation of the TemplateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Louwanda Lakiss Abstract A two-dimensional microporous fluorogallophosphate, named Mu-35, closely related to ULM-8, was hydrothermally synthesized by in situ generation of the structure-directing agent. The precursor of the structure-directing agent is ethylformamide, which is generated in situ by decomposition, and goes on to form ethylamine molecules that act as templates in the medium used for the synthesis. The fluorogallophosphate Mu-35 (Mu is Mulhouse), Ga3(PO4)2(HPO4)F3(C2H8N)2(C2H7N)0.5 (Z = 8), crystallizes in the orthorhombic space group Pbcn with the following unit cell parameters: a = 22.117(1), b = 17.3740(8), c = 10.1550(4) Å. The structure of fluorogallophosphate Mu-35 was determined from single-crystal XRD data. It exhibits anionic layers composed of an unusual arrangement of three-, five-, and eight-membered rings (MR) [Ga2PO2F, Ga3P2O4F, and Ga3P3O8, respectively], and intercalated by protonated and nonprotonated ethylamine molecules. Mu-35 was also characterized by powder XRD, SEM, elemental and thermal analyses, and solid-state NMR spectroscopy (1H, 13C, 19F, and 31P MAS and 1H- 31P HETCOR experiments). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Iron-Catalyzed Cyclopropanation with Trifluoroethylamine Hydrochloride and Olefins in Aqueous Media: In,Situ Generation of Trifluoromethyl Diazomethane,ANGEWANDTE CHEMIE, Issue 5 2010Bill Morandi Risikovermeidung: Die Titelumwandlung wurde zur Synthese von Trifluormethyl-substituierten Cyclopropanderivaten entwickelt (siehe Schema). Sie vermeidet die Herstellung von Trifluormethyldiazomethan und kombiniert mehrere Forschungsbereiche: Wasser als Reaktionsmedium, Eisenkatalyse sowie den Zugang zu reaktiven Intermediaten unter sicheren Bedingungen. [source] Development of a Novel Environmentally Friendly Electrolytic System by Using Recyclable Solid-Supported Bases for In Situ Generation of a Supporting Electrolyte from Methanol as a Solvent: Application for Anodic Methoxylation of Organic CompoundsCHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2005Toshiki Tajima Abstract We have successfully developed a novel environmentally friendly electrolytic system using recyclable solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent. It was found that solid-supported bases are electrochemically inactive at an electrode surface. It was also found that solid-supported bases dissociate methanol into methoxide anions and protons. Therefore, in the presence of solid-supported bases, it was clarified that methanol serves as both a solvent and a supporting electrolyte generated in situ. Anodic methoxylation of various compounds with solid-supported bases was carried out to provide the corresponding methoxylated products in good to excellent yields with a few exceptions. The methoxylated products and the solid-supported bases were easily separated by only filtration, and the desired pure methoxylated products were readily isolated simply by concentration of the filtrates. The separated and recovered solid-supported bases were recyclable for several times. [source] Doubly Stereocontrolled Asymmetric Aza-Henry Reaction with in situ Generation of N -Boc-Imines Catalyzed by Novel Rosin-Derived Amine Thiourea CatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Xianxing Jiang Abstract The doubly stereocontrolled organocatalytic aza-Henry reaction of nitroalkanes to N -Boc-imines generated in situ from a variety of substituted ,-amido sulfones was investigated for the first time, in general, affording the corresponding products with high to excellent yields (up to 93% yield) and enantioselectivities (up to 98% ee), and satisfactory diastereoselectivies (anti/syn up to 98:2). Furthermore, these organocatalysts based on rosin have been proved to be the very effective promoters for this catalytic asymmetric process along side the Cinchona alkaloid-derived catalysts. [source] Pronounced Catalytic Effect of a Micellar Solution of Sodium Dodecyl Sulfate (SDS) on the Efficient C-S Bond Formation via an Odorless Thia-Michael Addition Reaction through the in situ Generation of S -Alkylisothiouronium SaltsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2009Habib Firouzabadi Abstract A pronounced catalytic effect of sodium dodecyl sulfate (SDS) was observed on the in situ production of S -alkylisothiouronium salts via the reaction of primary, allyl and benzyl halides with thiourea in SDS droplets .Hydrolysis of the generated S -alkylisothiouronium salts in the palisade layer of the droplets produces the corresponding thiol moieties which are immediately added to the electron-deficient olefins that are present in the micellar core to produce the thia-Michael adducts. The entire route is an almost odorless process. The yields of the products are good to excellent and the method is applicable to large-scale operation without any problem. [source] ChemInform Abstract: In situ Generation of Novel Acyclic Diaminocarbene,Copper Complex.CHEMINFORM, Issue 37 2009Dimitri Hirsch-Weil Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Facile One-Pot Synthesis of 3-Unsubstituted-2,4-oxazolidinediones via in situ Generation of Carbamates from ,-Hydroxyesters Using Trichloroacetyl Isocyanate.CHEMINFORM, Issue 22 2009Yue H. Li Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: In situ Generation of n-Butanethiol and Its Reaction with Electron-Deficient Olefines.CHEMINFORM, Issue 31 2008Rogerio A. Gariani Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: In situ Generation of Ylides for Tandem Oxidation,Olefination Reactions of Unactivated Diols.CHEMINFORM, Issue 30 2008David J. Phillips Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Anionic, in situ Generation of Formaldehyde: A Very Useful and Versatile Tool in Synthesis.CHEMINFORM, Issue 31 2007Geoffrey Deguest Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Asymmetric Mannich Reactions with in situ Generation of Carbamate-Promoted Imines by an Organic Catalyst.CHEMINFORM, Issue 26 2007Jun Song Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Asymmetric Synthesis of ,-Hydroxy-,-trifluoromethylated Ketones via in situ Generation of Trifluoroacetaldehyde and Its Asymmetric Carbon,Carbon Bond Formation Reaction with Chiral Imines in Aqueous Media.CHEMINFORM, Issue 38 2006Kazumasa Funabiki Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] In situ Generation and Nucleophilic Capture of 1,n-Dial Equivalents from 1,n-Dioates (,,,-Diesters).CHEMINFORM, Issue 36 2006Thomas R. Hoye Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] In situ Generation of 3,3,3-Trifluoropropanal and Its Use for Carbon,Carbon Bond-Forming Reactions.CHEMINFORM, Issue 32 2006Takashi Yamazaki Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] In situ Generation of 2,3-Allenolates in the Coupling of Secondary Homopropargylic Alcohols and Aldehydes.CHEMINFORM, Issue 17 2006Pedro O. Miranda Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Direct Organocatalytic in situ Generation of Novel Push,Pull Dienamines: Application in Tandem Claisen,Schmidt/Iso-Aromatization Reactions.CHEMINFORM, Issue 3 2006Dhevalapally B. Ramachary Abstract For Abstract see ChemInform Abstract in Full Text. [source] In situ Generation of o-Iodoxybenzoic Acid (IBX) and the Catalytic Use of It in Oxidation Reactions in the Presence of Oxone as a Co-oxidant.CHEMINFORM, Issue 45 2005Arun P. Thottumkara Abstract For Abstract see ChemInform Abstract in Full Text. [source] Enantioselective Allylation of Aromatic Amines After in situ Generation of an Activated Cyclometalated Iridium Catalyst.CHEMINFORM, Issue 1 2005Chutian Shu Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Distinct Advantage of the in situ Generation of Quaternary Ammonium Fluorides under Phase-Transfer Conditions Toward Catalytic Asymmetric Synthesis.CHEMINFORM, Issue 34 2001Takashi Ooi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Versatile Synthetic Route to Dehydrobenzoannulenes via in situ Generation of Reactive Alkynes.CHEMINFORM, Issue 31 2001Michael L. Bell Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Electroenzymatic Synthesis of Chiral SulfoxidesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2006C. Kohlmann Abstract Chloroperoxidase (CPO) from Caldariomyces fumago (E.C.,1.11.1.10) is able to enantioselectively oxidize various sulfides to the corresponding (R)-enantiomer of the sulfoxides. For these oxidations the enzyme requires an oxidant. Most commonly, tert -butyl hydroperoxide (TBHP) and hydrogen peroxide are used. As it is known that these oxidants inactivate the enzyme, the enzymatic reaction was combined with the electrochemical in situ generation of hydrogen peroxide. As substrates for this combination of an enzymatic and an electrochemical reaction methyl p-tolyl sulfide, 1-methoxy-4-(methylthio)benzene and N-MOC- L -methionine methyl ester were used to carry out batch experiments. [source] Mu-35: A Fluorogallophosphate Obtained by In Situ Generation of the TemplateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Louwanda Lakiss Abstract A two-dimensional microporous fluorogallophosphate, named Mu-35, closely related to ULM-8, was hydrothermally synthesized by in situ generation of the structure-directing agent. The precursor of the structure-directing agent is ethylformamide, which is generated in situ by decomposition, and goes on to form ethylamine molecules that act as templates in the medium used for the synthesis. The fluorogallophosphate Mu-35 (Mu is Mulhouse), Ga3(PO4)2(HPO4)F3(C2H8N)2(C2H7N)0.5 (Z = 8), crystallizes in the orthorhombic space group Pbcn with the following unit cell parameters: a = 22.117(1), b = 17.3740(8), c = 10.1550(4) Å. The structure of fluorogallophosphate Mu-35 was determined from single-crystal XRD data. It exhibits anionic layers composed of an unusual arrangement of three-, five-, and eight-membered rings (MR) [Ga2PO2F, Ga3P2O4F, and Ga3P3O8, respectively], and intercalated by protonated and nonprotonated ethylamine molecules. Mu-35 was also characterized by powder XRD, SEM, elemental and thermal analyses, and solid-state NMR spectroscopy (1H, 13C, 19F, and 31P MAS and 1H- 31P HETCOR experiments). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] A Facile and Efficient Approach to N -Protected-,-Sulfinyl- enamines via C -Sulfinylation of Enamides and EnecarbamatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Yinhui Li Abstract A practical method has been developed for the C -sulfinylation of enamides and enecarbamates using sodium phenylsulfinate/methyltrichlorosilane (PhSO2Na/MeSiCl3) as the sulfinylating reagent and N,N -dimethylacetamide (DMAc) as the Lewis base promoter, which allows for the preparation of a variety of N -protected-,-sulfinylenamines in high yields and good stereoselectivities. The Lewis base is found to be important for both the in situ generation of the active sulfinylating species (PhSOCl) and the sulfinylation step. [source] Catalytic Use of a Soluble Organoindium(III) Species for Allylation and Crotylation of Ketones with BoronatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Miyuki Yamaguchi Abstract The unprecedented use of a soluble organoindium species, indium(III) hexamethyldisilazide [In(III)(hmds)3], for catalytic carboncarbon bond formations between ketones and boronates, is reported. Various functionalized tertiary homoallyl alcohols were generated easily in high yields. Remarkably, free hydroxy and primary amine functionalities proved to be tolerated. A rate acceleration and markedly improved diastereoselectivities were observed in the presence of methanol. Based on preliminary NMR experiments and the ,-selectivity with an ,-substituted boronate, we assume the in situ generation of reactive allylindium(III) species through catalytic boron-to-indium transmetalation. [source] Pentafluorophenylammonium Trifluoromethanesulfonimide: Mild, Powerful, and Robust Catalyst for Mukaiyama Aldol and Mannich Reactions between Ketene Silyl Acetals and Ketones or Oxime EthersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Ryohei Nagase Abstract Pentafluorophenylammonium trifluoromethanesulfonimide (C6F5N+H3,NTf2,) promotes Mukaiyama aldol and Mannich reactions using ketene silyl acetals with ketones and oxime ethers, respectively. The present robust method is mild, but powerful enough to utilize less accessible electrophiles such as enolizable ketones and oxime ethers to produce a variety of ,-hydroxy esters and ,-alkoxyamino esters, respectively. Mechanistic investigation revealed in situ generation of trimethylsilyl bistriflimide [Tf2N(TMS)], the truly active catalyst, which was supported by rational 1H,NMR measurements. [source] Enantioselective Aza-Morita,Baylis,Hillman Reaction Using Aliphatic ,-Amidosulfones as Imine SurrogatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Nacim Abermil Abstract The bifunctional catalyst 6,-deoxy-6,-acylamino-,-isocupreidine (1) served both as a base to trigger the in situ generation of N -sulfonylimine from readily available ,-amidosulfones and as a chiral nucleophile to initiate the enantioselective aza-Morita,Baylis,Hillman (aza-MBH) reaction. ,-Methylene-,-amino-,-alkyl carbonyl compounds, difficultly accessible previously, can now be synthesized in excellent yields and enantioselectivities. [source] One-Pot Thioetherification of Aryl Halides Using Thiourea and Alkyl Bromides Catalyzed by Copper(I) Iodide Free from Foul-Smelling Thiols in Wet Polyethylene Glycol (PEG 200)ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Habib Firouzabadi Abstract In this article, we have developed a new protocol for the thioarylation of structurally diverse alkyl bromides such as benzyl, cinnamyl, n -octyl, cyclohexyl, cyclopentyl, and tert -butyl bromides with aryl iodides, bromides and an activated chloride using thiourea catalyzed by copper(I) iodide in wet polyethylene glycol (PEG 200) as an eco-friendly medium in the presence of potassium carbonate at 80 and 100,°C under an inert atmosphere. The process is free from foul-smelling thiols which makes this method more practical for the thioetherification of aryl halides. Another important feature of this method is the variety of alkyl bromides which are commercially available for the in situ generation of thiolate ions with respect to the existing protocols in which the less commercially available thiols are directly used for the preparation of arylthio ethers. [source] Homobenzotetramisole-Catalyzed Kinetic Resolution of ,-Aryl-, ,-Aryloxy-, and ,-Arylthioalkanoic AcidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Xing Yang Abstract Effective kinetic resolutions of ,-aryl-, ,-aryloxy-, and ,-arylthioalkanoic acids have been achieved via in situ generation of their symmetrical anhydrides and enantioselective alcoholysis in the presence of homobenzotetramisole (HBTM) 3. [source] Copper(II) Triflate as a Source of Triflic Acid: Effective, Green Catalysis of Hydroalkoxylation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Mathieu J.-L. Abstract The hydroalkoxylation of dicyclopentadiene (DCPD) and norbornene (NB) with 2-hydroxyethyl methacrylate (HEMA) for the synthesis of industrially relevant monomers has been investigated with various metal-based Lewis acids and strong Brønsted acids. In the absence of other additives, copper(II) triflate is the most efficient catalyst system. Kinetics, electron spin resonance (ESR), catalyst poisoning and cross experiments indicate that triflic acid (TfOH) is the true active catalyst in these reactions. This in situ generation of TfOH occurs via reduction of Cu(OTf)2 by the olefin reagent (DCPD, NB). The copper ions present in the reaction mixture act as radical polymerization retardants, preventing polymerization of HEMA (which is observed with most other metal salts and strong Brønsted acids investigated), thus improving the selectivity and yield (up to 95%) for the desired products. These observations have led to the development of a highly effective green process, using bulk reagents (no solvent) and a cheap, metal-free catalyst system, based on TfOH and a phenolic radical inhibitor (2,5-di- tert -butylhydroxytoluene, BHT). [source] Pentacyclic Compounds by Samarium Diiodide-Induced Cascade Cyclizations of Naphthyl-Substituted 1,3-DionesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2008Ulrike Abstract Treatment of naphthyl-substituted cyclopentane-1,3-diones with the samarium diiodide- hexamethylphosphoramide (HMPA) complex in the presence of tert -butyl alcohol provided the expected tetracyclic diols with steroid-like structures. Surprisingly, reactions without the proton source led to the efficient formation of a new pentacyclic diol. In this case the toxic additive HMPA could be substituted by a combination of lithium bromide (in situ generation of samarium dibromide) and N,N -dimethylimidazolidone. The styrene-like alkene moiety of this product was used to prepare an ensemble of highly substituted pentacyclic steroid-like compounds. [source] | |||||||||||||||||||||||||