628-28-4Relevant articles and documents
Reaction of Oxetane with K+(18-crown-6)K- Complex; a Convenient Route to One-pot Metallation
Jedlinski, Zbigniew,Misiolek, Andrzej,Jankowski, Andrzej,Janeczek, Henryk
, p. 1513 - 1515 (1991)
A novel reaction of K+(18-crown-6)K- complex with oxetane yields the organometallic compound potassium γ-potassiopropoxide, a very efficient new metallating agent and a useful reagent in chemical synthesis.
Upgrading 1-butanol to unsaturated, carbonyl and aromatic compounds: A new synthesis approach to produce important organic building blocks
Boscolo, Mauricio,Metzker, Gustavo,Mora Vargas, Jorge,Orduna Ortega, Julieth,Tofaneli Morelato, Luiz Henrique
supporting information, p. 2365 - 2369 (2020/05/13)
Unsaturated, carbonyl and aromatic products were obtained by reacting 1-butanol or a 1-butanol:methanol mixture with a copper mixed metal oxide catalyst in a fixed bed reactor. The selectivities observed, mostly for the unsaturated and carbonyl products, can represent a new alternative and greener pathway for the production of fine-chemicals and organic building blocks.
Catalytic etherification of hydroxyl compounds to methyl ethers with 1,2-dimethoxyethane
Che, Penghua,Lu, Fang,Si, Xiaoqin,Xu, Jie
, p. 24139 - 24143 (2015/03/18)
1,2-Dimethoxyethane is explored for the first time as etherification agent for the acid-catalyzed synthesis of methyl ethers from biomass-derived hydroxyl compounds. H3PW12O40 catalyst can provide the formation of isosorbi
Synthesis of alkyl methyl ethers and alkyl methyl carbonates by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt complexes
Khusnutdinov,Shchadneva,Mayakova
, p. 790 - 795 (2014/08/18)
Alkyl methyl ethers and alkyl methyl carbonates were synthesized by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios, as well as reaction conditions, were found for selective formation of alkyl methyl ethers or alkyl methyl carbonates.
A crystalline catalyst based on a porous metal-organic framework and 12-tungstosilicic acid: Particle size control by hydrothermal synthesis for the formation of dimethyl ether
Liang, Da-Dong,Liu, Shu-Xia,Ma, Feng-Ji,Wei, Feng,Chen, Ya-Guang
supporting information; scheme or table, p. 733 - 742 (2011/05/06)
The strategy for obtaining a crystalline catalyst based on a porous copper-based metal-organic framework and 12-tungstosilicic acid with different particle sizes is reported. Through the control of hydrothermal synthesis and some simple treatments, catalyst samples with average particle diameters of 23, 105, and 450-μm, respectively, were prepared. This crystal catalyst has both the Bronsted acidity of 12-tungstosilicic acid and the Lewis acidity of the copper-based metal-organic framework, and has high density of accessible acid sites. Its catalytic activity was fully assessed in the dehydration of methanol to dimethyl ether. The effect of particle size on the catalytic activity of catalyst was studied, in order to select the particle size appropriate for avoiding the diffusion limitation in heterogeneous gas-phase catalysis. In the selective dehydration of methanol to dimethyl ether, this catalyst exhibited higher catalytic activity than the copper-based metal-organic framework, γ-alumina, and γ-alumina-supported 12-tungstosilicic acid catalysts. It showed high catalytic performances, even at higher space velocity or in the presence of excess water. In addition, the catalyst was also preliminarily assessed in the formation of ethyl acetate from acetic acid and ethylene. It also exhibited a high activity which was comparable with that of silica-supported 12-tungstosilicic acid catalyst. Copyright
PNA synthesis using a base-labile amino protecting group
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, (2008/06/13)
PNA synthesis using a base-labile amino protecting group Processes are described for preparing PNA oligomers, in which R0 is hydrogen, alkanoyl, alkoxycarbonyl, cycloalkanoyl, aroyl, heteroaroyl, or a group which favors the intracellular uptake of the oligomer, A and Q are amino acid residues, k and 1 are 0 to 20, n is 1-50, B is a nucleotide base which is customary in nucleotide chemistry, and Q0 is OH, NH2, or alkylamino which can be substituted by OH or NH2. In these processes, the amino acid residues and the structural components in which PG is a base-labile amino protecting group and B' is a nucleotide base which is protected on its exocyclic amino function, are coupled step-wise, in accordance with the solid-phase method, onto a polymeric support which is provided with an anchor group, and, after the construction is complete, the target compounds are cleaved from the polymeric support using a cleaving reagent. Intermediates of the PNA oligomers are also described, as are processes for their preparation.
The continuous acid-catalyzed dehydration of alcohols in supercritical fluids: A new approach to the cleaner synthesis of acetals, ketals, and ethers with high selectivity
Gray, William K.,Smail, Fiona R.,Hitzler, Martin G.,Ross, Stephen K.,Poliakoff, Martyn
, p. 10711 - 10718 (2007/10/03)
We report a new continuous method for forming ethers, acetals and ketals using solid acid catalysts, DELOXAN ASP or AMBERLYST 15, and supercritical fluid solvents. In the case of ether formation, we observe a high selectivity for linear alkyl ethers with little rearrangement to give branched ethers. Such rearrangement is common in conventional syntheses. Our approach is effective for a range of n-alcohols up to n-octanol and also for the secondary alcohol 2-propanol. In the reaction of phenol with an alkylating agent, the continuous reaction can be tuned to give preferential O- or C- alkylation with up to 49% O-alkylation with supercritical propene. We also investigate the synthesis of a range of cyclic ethers and show an improved method for the synthesis of THF from 1,4-butandiol under very mild conditions.
Lithium diisopropylamide solvated by monodentate and bidentate ligands: Solution structures and ligand binding constants
Remenar, Julius F.,Lucht, Brett L.,Collum, David B.
, p. 5567 - 5572 (2007/10/03)
6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15N]LDA) in toluene/pentane solutions containing a variety of mono- and polydentate ligands are reported. LDA forms exclusively dimers in the presence of n-BuOMe, Et2O, t-BuOMe, THF, 2- methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, dimethoxyethane, N,N,N',N'-tetramethylethylenediamine, and MeOCH2CH2NR2 (NR2 = NMe2, NEt2, pyrrolidino). Addition of 1,2-dipyrrolidinoethane and (2-pyrrolidinoethyl)dimethylamine provides monomer-dimer mixtures. Treatment of LDA with trans-N,N,N',N'-tetramethylcyclohexanediamine (TMCDA) or trans- 1-(dimethyl-amino)-2-isopropoxycyclohexane in hydrocarbons afford exclusively monomers. Sparteine binds only reluctantly, giving a mixture of unsolvated oligomers and monomer. Competitions of the ethereal ligands vs TMCDA afford binding constants and associated free energies for dimer solvation which are correlated with those obtained previously for lithium hexamethyldisilazide.
EFFICIENT AND/OR SELECTIVE METHYLATION BY DIAZOMETHANE OF ALCOHOLS, HALO ALCOHOLS, GLYCOLS, AMINO ALCOHOLS AND MERCAPTO ALCOHOLS WITH THE USE OF A PROTON-EXCHANGED X-TYPE ZEOLITE AS AN ACID-BASE BIFUNCTIONAL CATALYST
Takeuchi, Hiroshi,Kishioka, Hiroaki,Kitajima, Kunio
, p. 121 - 126 (2007/10/02)
Reactions of diazomethane with butanol, allyl alcohol and β- and γ-halo alcohols led to efficient methylation (giving the corresponding methyl ethers) with the use of a proton-excahnged X-type zeolite compared with H2SO4.The reactions with propylene and isobutylene glycols using the zeolite provided regioselective methylation of the primary OH rather than the secondary or tertiary OH, whereas regioselectivity was not observed in the reactions using H2SO4.The reactions with 2-aminoethanol and 2-mercaptoethanol showed high chemoselective S-methylation and N-monomethylation, respectively, in the presence of the zeolite instead of H2SO4.The mechanism for the reactions is proposed to involve acid-base bifunctional catalysis of the zeolite in which the acidic site reacts with diazomethane to form its conjugate acid, and the nucleophilicity of OH and SH groups is enhanced by the interaction of the basic site with the proton of the groups.
Photoinduced Electron Transfer Initiated Activation of Organoselenium Substrates as Carbocation Equivalents: Sequential One-Pot Selenylation and Deselenylation Reaction
Pandey, Ganesh,Soma Sekhar, B. B. V.
, p. 7367 - 7372 (2007/10/02)
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET activation of organoselenium substrates.Fluorescence quenching of 1DCN* by a number of organoselenium compounds (RCH2SeR', 1-4), correlation of the fluorescence quenching rate constants with the oxidation potentials of 1-4, and the dependence of photodissociation quantum yields of 1-4 on their concentration suggests the occurence of electron transfer processes between 1DCN* and 1-4.Steady-state photolysis of 1-4 in the presence of 1DCN* leads to the efficient one-electron oxidative heterolytic dissociation of the carbon-selenium bond to produce the carbocation (RCH2(1+) or equivalent) and radical-centered selenium species (R'Se(.)) via the intermediacy of cation-radical .Nucleophilic assistance in the fragmentation of (RCH2SeR')(1+.) by methanol has been suggested on the basis of products obtained from the control PET reaction of neopentyl phenyl selenide (8).The synthetic utility of these findings has been demonstrated for the deselenylation (Table 4) as well as one-spot sequential selenylation-deselenylation (Table 5) reactions.
