- Catalytic hydrogenation products of aromatic and aliphatic dicarboxylic acids
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Hydrogenation of aromatic dicarboxylic acids gave 100 % selectivity to respective cyclohexane dicarboxylic acid with 5 % Pd/C catalyst. 5 % Ru/C catalyst was observed to give over hydrogenation products at 493 K and at lower temperature (453 K) the selectivity for cyclohexane dicarboxylic acids was increased. Hydrogenation of phthalic acid with Ru-Sn/Al2O3 catalyst was observed to give phthalide instead of 1,2-benzene dimethanol or 2-hydroxy methyl benzoic acid. Ru-Sn/Al2O3 catalyst selectively hydrogenated the carboxylic group of cyclohexane dicarboxylic acids to give cyclohexane dimethanol. Use of proper catalysts and reaction conditions resulted in desired products.
- Shinde, Sunil B.,Deshpande, Raj M.
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p. 1137 - 1142
(2019/04/05)
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- Synthesis of phthalate-free plasticizers by hydrogenation in water using RhNi bimetallic catalyst on aluminated SBA-15
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In this study, rhodium-nickel bimetallic nanoparticles loaded on aluminated silica (RhNi/Al-SBA-15) were used as catalysts for the hydrogenation of phthalate in water to produce environmentally acceptable non-phthalate plasticizers. Chemical fluid deposition (CFD) was used to dope metals onto the aluminated silica support, which helped to create a uniform structure of RhNi on Al-SBA-15. The introduction of Ni helped to reduce the use of expensive Rh and increase the number of metal active sites by reducing the bimetallic nanoparticle size. Aluminated SBA-15 not only acted as the support for the RhNi bimetallic catalyst but also enhanced the reaction efficiency by introducing Br?nsted and Lewis acid sites and the absorption of phthalates on the catalyst in water. The physicochemical properties of prepared catalysts were characterized by N2 adsorption-desorption isotherm, X-ray diffraction (XRD), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The catalytic performance of the synthesized catalysts was evaluated with the hydrogenation of dimethyl phthalate (DMP). Despite the low solubility of DMP in water, the hydrogenation using Rh0.5Ni1.5/Al-SBA-15 was carried out with an 84.4% reaction yield (cis-?:?trans- = 97.5?:?2.5) at 80 °C using 1000 psi of H2 after 2 h.
- Phan-Vu, Duc-Ha,Tan, Chung-Sung
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p. 18178 - 18188
(2017/04/04)
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- Enantioselective Synthesis of ((1 R,2 R)-Cyclohexane-1,2-diyl)bis(methylene)dimethanesulfonate, a Lurasidone Hydrochloride Intermediate
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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.
- Ravi Ganesh,Pachore, Sharad S.,Pratap,Umesh,Basaveswara Rao,Murthy,Suresh Babu
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supporting information
p. 2676 - 2682
(2015/12/18)
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- A PROCESS FOR PREPARATION OF TRANS (LR,2R)-CYCLO HEXANE 1, 2-DICARBOXYLIC ACID
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A commercially viable process for industrial preparation of trans-(l R,2R)-cyclohexane 1,2- dicarboxylic acid represented by compound of Formula-I, wherein the compound has more than 99% HPLC purity. The compound of Formula-I is a key intermediate in preparation of Lurasidone hydrochloride which is a well known antipsychotic agent used for treatment of schizophrenia.
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Page/Page column 12
(2014/07/21)
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- Lipophilic oligopeptides for chemo- and enantioselective acyl transfer reactions onto alcohols
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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.
- Mueller, Christian E.,Zell, Daniela,Hrdina, Radim,Wende, Raffael C.,Wanka, Lukas,Schuler, Soeren M. M.,Schreiner, Peter R.
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p. 8465 - 8484
(2013/09/24)
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- CHARGE REVERSIBLE POLYMERS
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Described are charge reversible polymers, peptides and their resulting colloidal particles, comprising polymers and peptides having primary and secondary amines that are protected as easily hydrolysable amides. The amides are charge-reversible such that at neutral pH they are negatively charged but become positively charged at pH less than 6 and thus are relatively stable at neutral pH but quickly hydrolyze at pH below 6. Incorporating a drug in a micelle or a polymer comprised of the charge-reversible polymers or peptides provides a drug carrier for delivering the drug preferentially to the solid tumor or other targeted cells.
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Page/Page column 7
(2008/06/13)
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- Rational tuning chelate size of bis-oxazoline ligands to improve enantioselectivity in the asymmetric aziridination of chalcones
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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).
- Ma, Linge,Du, Da-Ming,Xu, Jiaxi
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p. 10155 - 10158
(2007/10/03)
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- Enantiomerically pure β-amino acids: A convenient access to both enantiomers of trans-2-aminocyclohexanecarboxylic acid
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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.
- Berkessel, Albrecht,Glaubitz, Katja,Lex, Johann
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p. 2948 - 2952
(2007/10/03)
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- Synthesis of polycarboxylic acids of cyclohexane series and their derivatives
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A preparation method was developed affording polycarboxylic acids of cyclohexane series: hexahydrophthalic, hexahydroisophthalic, hexahydroterephthalic, hexahydrotrimellitic, hexahydropyromellitic acid. Liquid phase catalytic hydrogenation was used in the synthesis. The hexahydrophthalic anhydride was applied to preparation of N-substituted monoamides of cyclohexanedicarboxylic acid and N-arylcyclohexanecarboxamides.
- Betnev,Obukhova,Budanov,Kolpashchikova,Betnev
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p. 519 - 521
(2007/10/03)
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- Synthesis of new C2-symmetrical diphosphines using chiral zinc organometallics
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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.
- Longeau, Alexia,Durand, Sandrine,Spiegel, Anja,Knoechel, Paul
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p. 987 - 990
(2007/10/03)
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- Process for making perhydroindole-2-carbonxylic acid
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A process for the asymmetric preparation of a compound of the formula STR1 wherein the hydrogen at 3a and 7a are of cis or trans configuration and their non-toxic, pharmaceutically acceptable acid addition salts comprising submitting a compound of the formula STR2 to a Hoffman reaction and reacting the resulting product with formaldehyde in the presence of cyanide ions and acid halide of benzoic acid or an aliphatic carboxylic acid of 1 to 5 carbon atoms to obtain a compound of the formula STR3 wherein R is acyl of benzoic acid or aliphatic carboxylic acid of 1 to 5 carbon atoms, cyclizing the latter to form a compound of the formula STR4 selectively hydrolyzing the latter with a dilute aqueous mineral acid to obtain a compound of the formula STR5 subjecting the latter to hydrolysis with a concentrated aqueous mineral acid to form the acid addition salt of a compound of claim 1 and optionally forming the free base.
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- CARBOXY AND SUBSTITUTED CARBOXY ALKANOYL AND CYCLOALKANOYL PEPTIDES
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Peptides of the formula STR1 wherein X is various amino or imino acids or esters are useful as hypotensive agents.
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