2305-32-0Relevant articles and documents
Highly-efficient Ru/Al-SBA-15 catalysts with strong Lewis acid sites for the water-assisted hydrogenation of: P -phthalic acid
Ahamad, Tansir,Kankala, Ranjith Kumar,Mao, Cong,Matsagar, Babasaheb M.,Wu, Kevin C.-W.,Yang, Yucheng,Zhang, Xueqin,Zheng, Jingwei
, p. 2443 - 2451 (2020/05/14)
Ruthenium nanoparticles supported onto aluminum-doped mesoporous silica catalysts (Ru/Al-SBA-15) are fabricated using hydrothermal and impregnation methods for catalysis application. The Ru/Al-SBA-15-3 catalyst at a Si/Al molar ratio of 3 exhibited excellent catalytic performance for the hydrogenation of p-phthalic acid with high conversion efficiency (100.0%) and cis-isomer selectivity (84.0%) in water. Moreover, this system displays exceptional stability and recyclability through preserving the conversion efficiency, as well as a cis-isomer selectivity of 90.2 and 83.3%, respectively, after reusing it fourteen times. Such an exceptional system can also be ideal for the hydrogenation of aromatic dicarboxylic acids and their ester derivatives in water. Strong Lewis acid sites due to doped Al species play significant roles in the hydrogenation reaction. Moreover, isotope labeling studies indicated that water molecules effectively participated in the hydrogenation reaction. Hydrogen and water contributed half of the hydrogen atoms for this hydrogenation reaction. In the end, a plausible mechanistic pathway for the hydrogenation of p-phthalic acid using the Ru/Al-SBA-15-3 catalyst in water is proposed.
2 or 4-substituted cyclohexane a acrylic compound-trans isomerization method of the
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Paragraph 0028-0029, (2017/02/17)
The invention discloses a cis-trans isomerization method of 2 or 4-substituted naphthenic acid compounds. The method comprises the following steps: converting a cis 2 or 4-substituted naphthenic acid compound into a trans 2 or 4-substituted naphthenic acid compound in the presence of a water-containing solvent, and under the conditions of pressure of 0-5 atm, temperature of 120 -200 DEG C and the action of strong alkali. The cis-trans isomerization method provided by the invention not only effectively improves the conversion efficiency of the reaction, has simple treatment and reduces environmental pollution, but also has the advantages of high yield, low cost and short preparation period.
Enantioselective Synthesis of ((1 R,2 R)-Cyclohexane-1,2-diyl)bis(methylene)dimethanesulfonate, a Lurasidone Hydrochloride Intermediate
Ravi Ganesh,Pachore, Sharad S.,Pratap,Umesh,Basaveswara Rao,Murthy,Suresh Babu
supporting information, p. 2676 - 2682 (2015/12/18)
A concise, economical, and highly enantioselective synthesis of bismesylate intermediate of lurasidone HCl, an antipsychotic, has been developed. The key steps involved in the synthesis are thionyl chloride-catalyzed esterification of tetrahydrophthalic anhydride in MeOH, epimerization of cis to trans isomer, hydrolysis of the diester, resolution of the diacid, reduction with Red-Al, and finally bismesylation of the corresponding diol, which provided the desired intermediate ((1 R,2 R)-cyclohexane-1,2-diyl)bis(methylene) dimethanesulfonate in overall good yield.
PROCESS FOR PREPARING BENZISOTHIAZOL-3-YL-PEPERAZIN-L-YL-METHYL-CYCLO HEXYL-METHANISOINDOL-1,3-DIONE AND ITS INTERMEDIATES
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Page/Page column 26, (2013/08/28)
The present invention discloses process for preparing benzisothiazol-3-yl- piperazin-l-yl-methyl-cyclo hexyl-methanisoindol-l,3-dione and intermediates thereof.
Lipophilic oligopeptides for chemo- and enantioselective acyl transfer reactions onto alcohols
Mueller, Christian E.,Zell, Daniela,Hrdina, Radim,Wende, Raffael C.,Wanka, Lukas,Schuler, Soeren M. M.,Schreiner, Peter R.
, p. 8465 - 8484 (2013/09/24)
Inspired by the extraordinary selectivities of acylases, we envisioned the use of lipophilic oligopeptidic organocatalysts for the acylative kinetic resolution/desymmetrization of rac- and meso-cycloalkane-1,2-diols. Here we describe in a full account the discovery and development process from the theoretical concept to the final catalyst, including scope and limitations. Competition experiments with various alcohols and electrophiles show the full potential of the employed oligopeptides. Additionally, we utilized NMR and IR-spectroscopic methods as well as computations to shed light on the factors responsible for the selectivity. The catalyst system can be readily modified to a multicatalyst by adding other catalytically active amino acids to the peptide backbone, enabling the stereoselective one-pot synthesis of complex molecules from simple starting materials.
Efficient and Practical Arene Hydrogenation by Heterogeneous Catalysts under Mild Conditions
Maegawa, Tomohiro,Akashi, Akira,Yaguchi, Kiichiro,Iwasaki, Yohei,Shigetsura, Masahiro,Monguchi, Yasunari,Sajiki, Hironao
experimental part, p. 6953 - 6963 (2010/02/28)
An efficient and practical arene hydrogenation procedure based on the use of heterogeneous platinum group catalysts has been developed. Rh/C is the most effective catalyst for the hydrogenation of the aromatic ring, which can be conducted in iPrOH under neutral conditions and at ordinary to medium H 2 pressures (10 atm). A variety of arenes such as alkylbenzenes, benzoic acids, pyridines, furans, are hydrogenated to the corresponding cyclohexyl and heterocyclic compounds in good to excellet yields. The use of Ru/C, less expensive than Rh/C, affords an effective and practical method for the hydrogenation of arenes including phenols. Both catalysts can be reused several times after simple filtration without any significant loss of catalytic activity.
Rational tuning chelate size of bis-oxazoline ligands to improve enantioselectivity in the asymmetric aziridination of chalcones
Ma, Linge,Du, Da-Ming,Xu, Jiaxi
, p. 10155 - 10158 (2007/10/03)
Chalcones were asymmetrically aziridinated with [N-(p-toluenesulfonyl) imino]phenyliodinane (PhI=NTs) as a nitrene source under catalysis of CuOTf and a series of cyclohexane-linked bis-oxazolines (cHBOXes), which are chelate size rationally tuned bis-oxazolines. The results indicate that highly enantioselective aziridination of chalcones with up to >99% ee have been achieved under catalysis of (S,S)-1,2-bis[(S)-(4-phenyl)oxazolin-2-yl] cyclohexane, which is the most-matched stereoisomer among cyclohexane-linked bis-oxazolines. It was also found that the enantioselectivity is not substituent-dependent with respect to chalcones in the present case, unlike with 1,8-anthracene-linked bis-oxazolines (AnBOXes).
Enantiomerically pure β-amino acids: A convenient access to both enantiomers of trans-2-aminocyclohexanecarboxylic acid
Berkessel, Albrecht,Glaubitz, Katja,Lex, Johann
, p. 2948 - 2952 (2007/10/03)
Enantiomerically pure trans-2-aminocyclohexanecarboxylic acid is an important building block for helical β-peptides. We report here that this amino acid can be obtained from trans-cyclohexane-1,2-dicarboxylic acid in good yield by a simple one-pot procedure comprising cyclization to the anhydride, amide formation with ammonia, and a subsequent Hofmann-type degradation with phenyliodine(III) bis(trifluoroacetate) (PIFA) as the oxidant. The N-Fmoc- and N-BOC-protected derivatives were obtained by treatment of the amino acid with Fmoc-OSu and BOC2O, respectively. The N-BOC derivative could be prepared in even better overall yield by a one-pot procedure leading directly from trans-cyclohexane-1,2-dicarboxylic acid to the N-BOC-protected amino acid. Both enantiomers of the starting trans-1,2-cyclohexanedicarboxylic acid can be obtained easily and in large quantities by separating commercially available racemic trans-1,2-cyclohexanedicarboxylic acid using either (R)- or (S)-1-phenethylamine. X-ray crystallography of the diastereomerically pure salt obtained from (R)-1-phenethylamine revealed that the configuration of the diacid component is (1R,2R), and not (1S,2S) as reported in the literature. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Phase transfer catalysis by tetraethylammonium bromide: Nucleophilic opening of anhydrides using potassium superoxide in aprotic medium
Singh, Sundaram,Shukla, Ajay Kumar,Singh, Krishna Nand
, p. 1184 - 1188 (2007/10/03)
Tetraethylammonium superoxide, generated in situ by the phase transfer reaction of potassium superoxide and tetraethylammonium bromide, brings about a clean cleavage of various anhydrides, particularly those with high molecular weight in dry dimethylformamide. As an outcome, succinic anhydride 1; glutaric anhydride 2; 3,3-dimethylglutaric anhydride 3; phthalic anhydride 4; diphenic anhydride 5; 1,2,3,4-tetrahydro-9-oxo-1,4-ethanonaphthalene-2,3- endo-dicarboxylic anhydride 6: 1,4,5,6,7,7-hexachloro-5-norbomene-2,3- dicarboxylic anhydride 7; endo-bicyclo [2.2.1] heptan-2-one-5,6-dicarboxylic anhydride 8; cis-5-norbornene-endo-2,3-dicarboxylic anhydride 9 and trans- 1,2-cyclohexane dicarboxylic anhydride 10 have been transformed into their corresponding dicarboxylic acids in fairly good yields. The report demonstrates the applicability of tetraethylammonium bromide as a phase transfer catalyst for efficient superoxide studies.
Synthesis of new C2-symmetrical diphosphines using chiral zinc organometallics
Longeau, Alexia,Durand, Sandrine,Spiegel, Anja,Knoechel, Paul
, p. 987 - 990 (2007/10/03)
The new C2-symmetrical diphosphines 1-4 of potential interest for asymmetric catalysis were prepared in protected form by a convergent synthesis based on the use of readily available (S,S)-1,2-cyclohexanedicarboxylic acid 8 and the phosphorus reagent (Et2N)2PLi·BH3.
