1193-79-9Relevant articles and documents
Acylation of methylfuran with Br?nsted and Lewis acid zeolites
Koehle, Maura,Zhang, Zhiqiang,Goulas, Konstantinos A.,Caratzoulas, Stavros,Vlachos, Dionisios G.,Lobo, Raul F.
, p. 90 - 101 (2018)
The acylation of methylfuran has been investigated using Br?nsted and Lewis acid zeolite catalysts. The highest reaction rate for acylation on a per gram basis is found on zeolite Beta with high aluminum content (Si/Al = 23) and the highest turnover frequency on a per metal site basis is found on zeolite Beta with low aluminum content (Si/Al = 138). Among Lewis acid zeolites, [Sn]-Beta shows higher turnover frequency than [Hf]-, [Zr]- or [Ti]-Beta. Similar apparent activation energies were found for [Al]-Beta with different Si/Al ratios and a lower apparent activation energy was found for [Sn]-Beta. Electronic structure calculations reveal that on both [Al]- and [Sn]-Beta the most favorable pathway follows the classic addition-elimination aromatic electrophilic substitution mechanism. The calculations also reveal that, on both [Al]- and [Sn]-Beta, the rate of methylfuran acylation is controlled by the dissociation of the C–O–C linkage of the anhydride while hydrogen elimination is the rate-determining step in the acylation of furan. The latter is in complete agreement with measured primary kinetic isotope effects. One remarkable and unexpected finding from our calculations is that the most favorable catalytic pathway in [Sn]-Beta involves Br?nsted acid catalysis by the silanol group of the hydrolyzed “open” site and not Lewis acid catalysis by the Sn metal center.
Synthesis, and antitubercular and antimicrobial activity of 1′-(4-chlorophenyl)pyrazole containing 3,5-disubstituted pyrazoline derivatives
Harikrishna,Isloor, Arun M.,Ananda,Obaid, Abdulrahman,Fun, Hoong-Kun
, p. 73 - 76 (2016)
A new series of 1′-(4-chlorophenyl)-5-(substituted aryl)-3′-(substituted aryl)-3,4-dihydro-2H,1′H-[3,4′]bipyrazolyl derivatives (6a-e, 8a-e, 10a-e) have been synthesized, characterized and screened for antimicrobial and antitubercular activity. Among the synthesized compounds, the minimum inhibition concentration of 10e was found to be as low as 1.56 μg ml-1 and that of 10c was 6.25 μg ml-1 as compared to the standard anti-tb drugs pyrazinamide and streptomycin.
Optimization for catalytic performances of Hβ zeolite in the acylation of 2-methylfuran by surface modification and solvents effect
Xiong, Yuannan,Chen, Wenqi,Zeng, Aiwu
, p. 1557 - 1574 (2017)
The liquid phase acylation of 2-methylfuran with acetic anhydride over modified Hβ zeolite was first conducted in a continuous flow reactor. The deactivation of Hβ zeolites was attributed to strong adsorption of reactants or products and was verified by GC–MS and 13C MAS NMR. Deactivated zeolites can be regenerated to their original state by calcination. The acidic properties was adjusted by surface modification on Hβ, the maximum yield of 89.5?mol% and selectivity of 100?% were obtained over tartaric acid modified by Hβ. The deposition of tetraethoxysilane to silica on Hβ contributed to enhancing the catalytic stability. Combined with the results of NH3-TPD and Py-FTIR, the amount of Broensted acids played a major role on catalytic activity. A close relationship between the catalytic stability and the ratio of the amount of strong to weak acids at 1:1 was highlighted here. The solvents' effect on the catalytic performances was examined, and 1,2-dichloroethane with moderate polarity exerted a positive effect on catalytic stability.
Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses
Liang, Fengying,Eda, Kazuo,Okazoe, Takashi,Wada, Akihiro,Mori, Nobuaki,Konishi, Katsuhiko,Tsuda, Akihiko
, p. 6504 - 6517 (2021/05/06)
The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl3, SOCl2, or COCl2. In this study, we found that VR is readily obtained from a CHCl3 solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O2 bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO2 as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl3, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.
Synthesis method of 2,5-furandicarboxylic acid
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Paragraph 0026; 0031-0033; 0040; 0045-0047; 0054; 0059-0061, (2020/06/09)
The invention discloses a synthesis method of 2,5-furandicarboxylic acid. The synthesis method comprises the following steps: 1, hydrogenation of furfural into methyl furan; 2, acetylation of methyl furan; 3, hydrogenation of 5-methyl-2-acetylfuran; and 4, oxidation of 2-methyl-5-ethylfuran. According to the invention, a green renewable bio-based platform compound furfural is used as a raw material; and compared with a process for preparing 2,5-furandicarboxylic acid by using 5-hydroxymethylfurfural as a raw material, the method disclosed by the invention has the advantages that the source ofthe used raw material is wider, the raw material is easy to produce, productivity is higher, the cost of the raw material is lower, the cost of a used oxidation catalyst is low, and large-scale production is facilitated. Compared with a noble metal complex catalyst used in a process adopting CO carbonylation for carbon chain growth, a carbon chain growth strategy catalyst used in the invention issolid acid, so cost is greatly reduced.
Method for producing furandicarboxylic acid and derivatives thereof from furfural
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Paragraph 0034; 0039-0042; 0053; 0058-0061, (2020/06/05)
The invention discloses a method for producing furandicarboxylic acid and derivatives thereof from furfural. The method comprises the following steps: furfural is reduced to 2-methylfuran under the hydrogen condition; acetylation reaction is carried out on 2-methylfuran to obtain 5-methyl-2-acetylfuran; 5-methyl-2-acety furan reacts with ester to obtain methyl 5-methyl-2-furanformate, methyl 5-methyl-2-furanformate is oxidized into monomethyl 2,5-furandicarboxylate under the oxygen condition, and monomethyl 2,5-furandicarboxylate is hydrolyzed into monomethyl 2,5-furandicarboxylate or furtheresterified with methyl alcohol to generate dimethyl 2,5-furandicarboxylate. The cheap five-carbon furan compound furfural is used as a raw material, and the 2 5-furandicarboxylic acid and the derivatives thereof are prepared by a strategy of increasing a carbon chain, so that the cost of the raw material is greatly reduced. The product provided by the invention has high purity and can be directlyused as a polymerization monomer of PET polyester.
Cobalt-Catalyzed Oxygenation/Dearomatization of Furans
Oswald, Jonathan P.,Woerpel
, p. 9067 - 9075 (2018/05/29)
The dearomatization of aromatic compounds using cobalt(II) acetylacetonate with triplet oxygen and triethylsilane converts furans, benzofurans, pyrroles, and thiophenes to a variety of products, including lactones, silyl peroxides, and ketones.
Biocatalysis with the milk protein β-lactoglobulin: Promoting retroaldol cleavage of α,β-unsaturated aldehydes
Gowda, Vishruth,Foley, Brendan,Du, Jasmine,Esteb, Megan,Watanabe, Coran M. H.
supporting information, p. 2210 - 2213 (2018/04/05)
Enzymes with a hydrophobic binding site and an active site lysine have been suggested to be promiscuous in their catalytic activity. β-Lactoglobulin (BLG), the principle whey protein found in milk, possesses a central calyx that binds non-polar molecules. Here, we report that BLG can catalyze the retro-aldol cleavage of α,β-unsaturated aldehydes making it a naturally occurring protein capable of catalyzing retro-aldol reactions on hydrophobic substrates. Retroaldolase activity was seen to be most effective on substrates with phenyl or naphthyl side-chains. Use of a brominated substrate analogue inhibitor increases the product yield by a factor of three. BLG's catalytic activity and its ready availability make it a prime candidate for the development of commercial biocatalysts.
Production of p-Methylstyrene and p-Divinylbenzene from Furanic Compounds
Koehle, Maura,Sara?i, Erisa,Dauenhauer, Paul,Lobo, Raul F.
, p. 91 - 98 (2017/01/17)
A four-step catalytic process was developed to produce p-methylstyrene from methylfuran, a biomass-derived species. First, methylfuran was acylated over zeolite H-Beta with acetic anhydride. Second, the acetyl group was reduced to an ethyl group with hydrogen over copper chromite. Third, p-ethyltoluene was formed through Diels–Alder cycloaddition and dehydration of 2-ethyl-5-methyl-furan with ethylene over zeolite H-Beta. Dehydrogenation of p-ethyltoluene to yield p-methylstyrene completes the synthesis but was not investigated because it is a known process. The first two steps were accomplished in high yield (>88 %) and the Diels–Alder step resulted in a 67 % yield of p-ethyltoluene with a 99.5 % selectivity to the para isomer (final yield of 53.5 %). The methodology was also used for the preparation of p-divinylbenzene. It is shown that acylation of furans over H-Beta zeolites is a highly selective and high-yield reaction that could be used to produce other valuable molecules from biomass-derived furans.
A salen-Co3+ catalyst for the hydration of terminal alkynes and in tandem catalysis with Ru-TsDPEN for the one-pot transformation of alkynes into chiral alcohols
Wang, Shoufeng,Miao, Chengxia,Wang, Wenfang,Lei, Ziqiang,Sun, Wei
, p. 1612 - 1616 (2014/06/24)
The cobalt-salen complex (C1:[(salen)Co3+(OAc)]; salen= N,N'-bis(salicylidene)ethylenediamine, OAc=acetate) was found to efficiently promote the hydration of terminal alkynes to give methyl ketones in the presence of the H2SO4 cocatalyst. In addition, the one-pot transformation of alkynes into chiral alcohols through tandem catalysis by catalyst C1 coupled with a ruthenium-TsDPEN complex (C3: [(R,R-TsDPEN)Ru 2+(cymene)]; TsDPEN=(1R,2R)-N-(p-toluenesulfonyl)-1,2- diphenylethylenediamine, cymene=1-methyl-4-(1-methylethyl)benzene) catalyst was realized with excellent yields and enantioselectivities. Stay hydrated: The salen-Co3+ (1) complex is found to efficiently promote the hydration of terminal alkynes to give methyl ketones in the presence of the H 2SO4 cocatalyst. In addition, the one-pot transformation of alkynes into chiral alcohols through tandem catalysis of 1 with the ruthenium catalyst 2 is realized in excellent yields and enantioselectivities.
