111-11-5Relevant articles and documents
Malononitrile as acylanion equivalent
F?rster, Sebastian,Tverskoy, Olena,Helmchen, Günter
, p. 2803 - 2806 (2008)
The oxidation of derivatives of malononitrile with peracid in methanol proceeds with loss of the cyano groups to yield methyl esters in high yield. The method was applied to a variety of malononitrile derivatives, some of which were prepared by Pd- or Ir-catalyzed asymmetric allylic substitution. Georg Thieme Verlag Stuttgart.
Mechanistic Insights into Aerobic Oxidative Methyl Esterification of Primary Alcohols with Heterogeneous PdBiTe Catalysts
Mannel, David S.,King, Jesaiah,Preger, Yuliya,Ahmed, Maaz S.,Root, Thatcher W.,Stahl, Shannon S.
, p. 1038 - 1047 (2018)
Aerobic oxidative methyl esterification of primary alcohols is an important chemical transformation that converts a nucleophile (alcohol) into a versatile electrophile (methyl ester). We recently discovered a heterogeneous PdBiTe/C catalyst that exhibits the highest activity yet reported for this transformation. Bi and Te serve as synergistic promoters that enhance both the rate and yield of the reactions relative to reactions employing Pd alone or Pd in combination with Bi or with Te as the sole promoter. Here, we report a mechanistic study of the oxidative methyl esterification of benzyl alcohol and 1-octanol to provide insights into the overall multistep transformation as well as the role of the Bi and Te in the reaction. The catalytic rates of the oxidative esterification of benzyl alcohol and octanol with Pd, PdBi, PdTe, and PdBiTe catalysts exhibit a saturation dependence on [alcohol] and [K2CO3] and a first-order dependence on pO2. Hammett studies of benzyl alcohol oxidation reveal opposing electronic trends for initial rates of oxidation of alcohol to aldehyde (negative ? value) and the oxidation of aldehyde to methyl ester (positive ? value). These data and complementary kinetic isotope effect data support a Langmuir-Hinshelwood mechanism in which a surface-bound alkoxide or hemiacetal intermediate undergoes rate-limiting β-hydride elimination. Molecular oxygen participates in this process, as revealed by a first-order dependence on pO2. X-ray photoelectron and X-ray absorption spectroscopic methods show that the promoters undergo oxidation in preference to Pd, maintaining the Pd surface in the active metallic state and preventing inhibition by surface Pd-oxide formation. Collectively, these results provide valuable insights into the synergistic benefits of multiple promoters in heterogeneous catalytic oxidation reactions.
Structure and catalysis of layered Nb-W oxide constructed by the self-assembly of nanofibers
Okumura, Kazu,Ishida, Soichiro,Takahata, Ryota,Katada, Naonobu
, p. 197 - 203 (2013)
Treatment of crystalline Nb2O5-WOx fibers with an aqueous solution of oxalic or tartaric acid resulted in the formation of nanosheets with a layered structure in which fibers were self-assembled. The oxalic and tartaric acid-treated oxides had dense layered structures containing mesopores between the layers with mean diameters of 4.6 and 1.9 nm, respectively. These oxides exhibited much higher recyclability as catalysts for the Friedel-Crafts alkylation and acylation of anisole compared to untreated ones. Furthermore, no deactivation was observed in a continuous flow process for the reaction of anisole and benzyl alcohol at least over 87 days' period in which turnover number = 33,000 was obtained. The improved catalytic performance was ascribed to the formation of layered structure, which was preserved during reactions.
Hydroxylamine Reactions with Peroxide Products of Alkenes Ozonolysis
Legostaeva, Yu. V.,Garifullina,Nazarov,Ishmuratova,Ishmuratov, G. Yu.
, p. 1122 - 1126 (2018)
Reactions were studied of peroxide ozonolysis products obtained from linear and cyclic alkenes with hydroxylamine prepared in situ from NH2OH·HCl by hydrogen chloride neutralization with sodium acetate. A one-pot reactions sequence was performed: alkene oxidation with ozone → reduction to a carbonyl compound with hydroxylamine → condensation of the carbonyl compound with hydroxylamine providing a possibility of direct transformation of alkenes in keto- and aldoximes excluding the stage of preparation and isolation of the carbonyl compound.
Synthesis, characterization and reactivity of (dithiolato)indium complexes
Anderson, Timothy S.,Briand, Glen G.,Brüning, Ralf,Decken, Andreas,Margeson, Matthew J.,Pickard, Heidi M.,Trevors, Eric E.
, p. 101 - 108 (2017)
We have synthesized indium complexes incorporating tetradentate dithiolate ligands. The 1:1 reaction of InX3 (X?=?OAc, NO3) and the corresponding dithiol or dithiolate yielded the compounds [(SOOS)In(py)(NO3)] (1), [(SNNS)In(OAc)] (2), [In(μ-SNNS)2(μ-OMe)In][NO3] (3), [(SNNSPr)In(OAc)] (4), [(NNS2)In(OAc)] (5) and [(NNS2)In(NO3)] (6) [H2(SOOS)?=?2,2′-(ethylenedioxy)diethanethiol; H2(SNNS)?=?N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)ethylenediamine; H2(SNNSPr)?=?N,N′-diethyl-N,N′-bis(2-mercaptoethyl)propanediamine; H2(NNS2)?=?N,N-diethyl-N′,N′-bis(2-mercaptoethyl)ethanediamine]. The solid-state structures of 1, 2 and 4–6 are mononuclear and show a tetradentate SOOS/SNNS/NNS2 ligand and a distorted octahedral (1) or trigonal bipyramidal (2, 4–6) coordination geometry at indium. Compound 3 is dinuclear, with the indium centres bridged by a -OMe oxygen atom and a thiolate sulfur atom of chelating tetradentate ligands, respectively. InX3 (X?=?Cl, NO3) were found to be useful Lewis acid catalysts for the aldol reaction of benzaldehyde and 1-(trimethylsiloxy)cyclohexene under ambient conditions, while compounds 1–6 show moderate activity as catalysts for the esterification of stearic acid and transesterification of methyl stearate and glyceryl trioctanoate.
Magnesia-supported gold nanoparticles as efficient catalysts for oxidative esterification of aldehydes or alcohols with methanol to methyl esters
Wan, Xiaoyue,Deng, Weiping,Zhang, Qinghong,Wang, Ye
, p. 147 - 154 (2014)
Magnesia-supported gold nanoparticles were found to be highly efficient catalysts for the oxidative esterification of methacrolein (MAL) with methanol in the presence of molecular oxygen into methyl methacrylate (MMA) under liquid base-free conditions. MAL conversion of 98% and MMA selectivity of 99% were obtained over the Au/MgO catalyst at 343 K after a 2 h reaction. Besides the Au nanoparticles, the support also played pivotal roles in the oxidative esterification of MAL. The support with higher density of basic sites, particularly stronger basic sites, showed better performances for the formation of MMA. The enhancement of the intermediate formation by the basic sites is proposed to be the key reason for the superior activity of the Au/MgO catalyst. Our studies on the size effect of Au nanoparticles reveal that smaller Au nanoparticles favor the transformation of MAL, and the turnover frequency increases with decreasing mean size of Au nanoparticles. This suggests that the Au-catalyzed oxidative esterification of MAL is a structure-sensitive reaction. We have demonstrated that the Au/MgO catalyst is also applicable to the oxidative esterification of different aldehydes and alcohols.
(BDP)CuH: A "hot" Stryker's reagent for use in achiral conjugate reductions
Baker, Benjamin A.,Boskovic, Zarko V.,Lipshutz, Bruce H.
, p. 289 - 292 (2008)
(Chemical Equation Presented) A ligand-modified, economical version of Stryker's reagent (SR) has been developed based on a bidentate, achiral bis-phosphine. Generated in situ, "(BDP)CuH" smoothly effects conjugate reductions of a variety of unsaturated substrates, including those that are normally unreactive toward SR. Substrate-to-ligand ratios typically on the order of 1000-10000:1 can be used leading to products in high yields.
Composition of lipids from sunflower pollen (Helianthus annuus)
Schulz, Stefan,Arsene, Cristian,Tauber, Marianne,McNeil, Jeremy N.
, p. 325 - 336 (2000)
The contents of the pollen lipids of the sunflower Helianthus annuus are described. The major component is the seco-triterpene helianyl octanoate, followed by new β-diketones as second major group of compounds. They exhibit a shorter chain length and often other positions of the functional group compared to already known β-diketones. Of particular note are the 1-phenyl- β-diketones, not previously reported from nature. Further lipid classes present are related hydroxyketones and diols. Interestingly, new β- dioxoalkanoic acids are present in the extracts, which most likely are biogenetic precursors of the diketones. Additionally, we investigated the composition of the pollen coat which resembles the total extract, but lacks the dioxoalkanoic acids and certain estolides. (C) 2000 Elsevier Science Ltd.
Pore-expanded SBA-15 sulfonic acid silicas for biodiesel synthesis
Dacquin,Lee,Pirez,Wilson
, p. 212 - 214 (2012)
Here we present the first application of pore-expanded SBA-15 in heterogeneous catalysis. Pore expansion over the range 6-14 nm confers a striking activity enhancement towards fatty acid methyl ester (FAME) synthesis from triglycerides (TAG), and free fatty acid (FFA), attributed to improved mass transport and acid site accessibility.
Hydrazides of Organic Acids in the Transformations of the Peroxide Products of Non-1-ene Ozonolysis
Myasoedova, Yu. V.,Garifullina,Nurieva,Ishmuratov, G. Yu.
, p. 1712 - 1715 (2019)
The reaction of hydrazides of alicyclic capric and aromatic benzoic and p-hydroxybenzoic acids with the peroxide product of non-1-ene ozonolysis was studied. Capric acid hydrazide exhibits the strongest reducing properties in aprotic solvents (methylene chloride, THF) and leads to chemoselective and high-yield (~ 80%) formation of the corresponding acylhydrazone. p-Hydroxybenzoic acid hydrazide forms a similar derivative with a yield of 67% only in THF.
