- Using Mg-Al Mixed Oxide and Reconstructed Hydrotalcite as Basic Catalysts for Aldol Condensation of Furfural and Cyclohexanone
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This study presents results on aldol condensation of furfural and cyclohexanone in presence of Mg-Al hydrotalcite-derived materials as solid basic catalysts at reaction temperatures from 25 to 90 °C and a cyclohexanone to furfural molar ratio of 1–10. Mg-Al mixed oxide exhibited reasonable activity with furfural conversion of ca. 50 % after 180 min of the reaction at T=90 °C. The activity of reconstructed hydrotalcite was much higher with furfural conversion close to 100 % at short reaction times. In comparison with Mg-Al mixed oxide, the initial reaction rate has increased 30–50 times. Under similar reaction conditions, cyclohexanone self-condensation on HTC-derived catalysts could not compete with aldol condensation because the former reaction was inhibited by produced water. The change in CH/F molar ratio influenced both furfural conversion and product selectivity; higher furfural content in the reaction mixture favored the second condensation step.
- Kikhtyanin, Oleg,Kadlec, David,Velvarská, Romana,Kubi?ka, David
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Read Online
- Redox-Neutral Cobalt(III)-Catalyzed C-H Activation/Annulation of α,β-Unsaturated Oxime Ether with Alkyne: One-Step Access to Multisubstituted Pyridine
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A redox neutral Co(III)-catalyzed annulation of α,β-unsaturated oxime ether with alkyne has been reported. Multisubstituted pyridines were synthesized in good yields without the use of any heavy metal oxidants. The developed methodology tolerates a variety of functional groups. Notably, this transformation has been applied to the late-stage modification of the bioactive molecule dehydropregnenolone.
- Mohanty, Smruti Ranjan,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Das Adhikari, Gopal Krushna,Ravikumar, Ponneri Chandrababu
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p. 1074 - 1083
(2021/01/14)
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- Synthesis and antimicrobial activities of (4,5,6,7-tetrahydro-1H-indazol- 2(3H)-yl)thiazole derivatives
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Synthesis, characterization and investigation of antimicrobial activities of ten novel tetrahydroindazolylthiazoles is presented. Their structures were determined using 1H and 13C NMR, FAB(+)-MS and HRMS analyses. Among the derivativ
- ?aczkowski, Krzysztof Z.,Misiura, Konrad,Biernasiuk, Anna,Malm, Anna
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p. 960 - 967
(2014/10/15)
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- Fe3O4 nanoparticles as an efficient and magnetically recoverable catalyst for the synthesis of α β-unsaturated heterocyclic and cyclic ketones under solvent-free conditions
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An efficient and green procedure has been developed for the synthesis of monoarylidenes of cyclic and heterocyclic ketones. The reaction was carried out under solvent-free conditions in the presence of a catalytic amount of nanosized magnetite (Fe3O4). The catalyst was easily removed by using an external magnet. The structures of the products were deduced from their 1H NMR, 13C NMR, and infrared spectroscopy and mass spectrometry. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Alishiri, Tooba,Oskooei, Hossein A.,Heravi, Majid M.
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p. 3357 - 3362
(2013/10/01)
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- Ultrasound mediation for efficient synthesis of monoarylidene derivatives of homo- and heterocyclic ketones
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Ultrasonic irradiation was efficiently used for high yield synthesis of monoarylidene derivatives of cyclic systems directly from the reaction of ketone with various aldehydes under solvent-free conditions. Reactions took place rapidly in the presence of catalytic amounts of pyrrolidine, while no significant formation of the undesired bis by-products was observed. Moreover, the procedure was applicable to both homo- and heterocyclic ketones.
- Mojtahedi, Mohammad M.,Abaee, M. Saeed,Samianifard, Mehdieh,Shamloo, Akram,Padyab, Masoomeh,Mesbah, A. Wahid,Harms, Klaus
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p. 924 - 930
(2013/03/13)
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- Aldol condensations of aldehydes and ketones catalyzed by primary amine on water
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Potassium glycinate-catalyzed aldol condensation reactions of aromatic aldehydes and ketones on water at room temperature have been developed. Under optimal conditions, various condensation adducts are furnished in up to 63 % yield. By simple separation of the oil phase, potassium glycinate-containing water is reused to catalyze aldol condensation for six runs without loss of catalytic activity. Theoretical investigation reveals correlation between the yields and dehydroxylation energy barriers of aldol products, reasonably low activation energy of 11.9 kcal/mol for transition state formation in condensation of benzaldehyde and acetone, vibrations between aldol donor and acceptor, which correspond to the only imaginary frequency (-179.8i).
- Zhang, Xu,Xiong, Yan,Zhang, Shuting,Ling, Xuege,Wang, Jinyue,Chen, Changguo
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experimental part
p. 751 - 755
(2012/07/28)
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- Facile synthesis and characterization of substituted pyrimidin-2(1H)-ones and their chalcone precursors
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A new and efficient method has been developed for the quantitative transformation of chalcones to pyrimidine frame work vSa solid support catalysis, Silica supported sulphuric acid (SSA) efficiently catalyzed the reaction of α-β-unsaturated earbonyl, chalcones (140) with urea to afford substituted pyriniidin-2(1H)-ones (11-20) hi good to excellent yield. The interesting behaviour of SSA lies in the thct that it can be re-used after simple washing with chloroform thereby rendering this procedure more economical, The chemical structures were confirmed by analytical data as well as spectroscopic means.
- Ajani, Olayinka Oyewale,Ituen, Ruth Itoroabasi,Falomo, Ayorinde
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experimental part
p. 59 - 67
(2012/06/01)
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- Facile separation catalyst system: Direct diastereoselective synthesis of (E)-α,β-unsaturated ketones catalyzed by an air-stable Lewis acidic/basic bifunctional organobismuth complex in ionic liquids
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The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex and [Bmim]BF4 is highly efficient in the cross-condensation of aldehydes with ketones. Through switching the reaction from homogeneous to heterogeneous, the system shows facile separation ability and facile reusability.
- Qiu, Renhua,Qiu, Yimiao,Yin, Shuangfeng,Song, Xingxing,Meng, Zhengong,Xu, Xinhua,Zhang, Xiaowen,Luo, Shenglian,Au, Chak-Tong,Wong, Wai-Yeung
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supporting information; scheme or table
p. 1767 - 1771
(2011/02/23)
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- Highly Enantioselective Hydrogenation of α-Arylmethylene Cycloalkanones Catalyzed by Iridium Complexes of Chiral Spiro Aminophosphine Ligands
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The highly efficient asymmetric hydrogenation of α-arylmethylene cycloalkanones catalyzed by Ir-complexes of chiral spiro aminophosphine ligands was developed, providing chiral exo-cyclic allylic alcohols at high yields with excellent enantioselectivities (up to 97% ee) and high turnover numbers (S/C up to 10,000). This new reaction provided an efficient method for the synthesis of the key intermediate of the active form of the anti-inflammatory loxoprofen.
- Xie, Jian-Bo,Xie, Jian-Hua,Liu, Xiao-Yan,Kong, Wei-Ling,Li, Shen,Zhou, Qi-Lin
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supporting information; experimental part
p. 4538 - 4539
(2010/06/17)
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- Carbamoyloximes as novel non-competitive mGlu5 receptor antagonists
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Hit-to-lead optimization of a HTS hit led to new carbamoyloxime derivatives. After identification of an advanced hit (8d) the CYP enzyme inhibitory activity of this class of compounds was successfully eliminated. Systematic exploration of different parts of the advanced hit led us to some promising lead compounds with mGluR5 affinities comparable to that of MPEP.
- Galambos, Janos,Wagner, Gabor,Nogradi, Katalin,Bielik, Attila,Molnar, Laszlo,Bobok, Amrita,Horvath, Attila,Kiss, Bela,Kolok, Sandor,Nagy, Jozsef,Kurko, Dalma,Bakk, Monika L.,Vastag, Monika,Saghy, Katalin,Gyertyan, Istvan,Gal, Krisztina,Greiner, Istvan,Szombathelyi, Zsolt,Keser, Gyoergy M.,Domany, Gyoergy
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scheme or table
p. 4371 - 4375
(2010/10/02)
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- Synthesis of hydrogenated indazole derivatives starting with α,β-unsaturated ketones and hydrazine derivatives
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The reaction of hydrazine derivatives with α,β-unsaturated ketones, such as cyclohexenyl(phenyl)methanone and (E)-2-benzylidenecyclohexanone, were investigated. The reaction between methylhydrazine and e.g., cyclohexenyl(phenyl)methanone was particularly interesting as 3a,4,5,6,7,7a-hexahydro-1-methyl-3-phenyl-1H-indazole was obtained as the major product together with 4,5,6,7-tetrahydro-2-methyl-3-phenyl-2H-indazole as a minor product.
- Nakhai, Azadeh,Bergman, Jan
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experimental part
p. 2298 - 2306
(2009/07/11)
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- Synthesis and molecular modeling of some novel hexahydroindazole derivatives as potent monoamine oxidase inhibitors
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A novel series of 2-thiocarbamoyl-2,3,4,5,6,7-hexahydro-1H-indazole and 2-substituted thiocarbamoyl-3,3a,4,5,6,7-hexahydro-2H-indazoles derivatives were synthesized and investigated for the ability to inhibit the activity of the A and B isoforms of monoamine oxidase (MAO). The target molecules were identified on the basis of satisfactory analytical and spectra data (IR, 1H NMR, 13C NMR, 2D NMR, DEPT, EI-MASS techniques and elemental analysis). Synthesized compounds showed high activity against both the MAO-A (compounds 1d, 1e, 2c, 2d, 2e) and the MAO-B (compounds 1a, 1b, 1c, 2a, 2b) isoforms. In the discussion of the results, the influence of the structure on the biological activity of the prepared compounds was delineated. It was suggested that non-substituted and N-methyl/ethyl bearing compounds (except 2c) increased the inhibitory effect and selectivity toward MAO-B. The rest of the compounds, carrying N-allyl and N-phenyl, appeared to select the MAO-A isoform. The inhibition profile was found to be competitive and reversible for all compounds. A series of experimentally tested (1a-2e) compounds was docked computationally to the active site of the MAO-A and MAO-B isoenzyme. The autodock 4.01 program was employed to perform automated molecular docking. In order to see the detailed interactions of the docked poses of the model inhibitors compounds 1a, 1d, 1e and 2e were chosen because of their ability to reversibly inhibit the MAO-B and MAO-A and the availability of experimental inhibition data. The differences in the intermolecular hydrophobic and H-bonding of ligands to the active site of each MAO isoform were correlated to their biological data. Observation of the docked positions of these ligands revealed interactions with many residues previously reported to have an effect on the inhibition of the enzyme. Excellent to good correlations between the calculated and experimental Ki values were obtained. In the docking of the MAO-A complex, the trans configuration of compound 1e made various very close interactions with the residues lining the active site cavity these interactions were much better than those of the other compounds tested in this study. This tight binding observation may be responsible for the nanomolar inhibition of form of MAOA. However, it binds slightly weaker (experimental Ki = 1.23 μM) to MAO-B than to MAO-A (experimental Ki = 4.22 nM).
- Goekhan-Kelekci, Nesrin,Simsek, Oe. Oezguen,Ercan, Ayse,Yelekci, Kemal,Sahin, Z. Sibel,Isik, Samil,Ucar, Guelberk,Bilgin, A. Altan
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experimental part
p. 6761 - 6772
(2009/12/28)
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