- The synthesis of rigid polycyclic structures for the study of diatropic or steric effects of a phenyl ring on CF bond
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Polycyclic compounds 1a-c were synthesized to study the diatropic effects of a flanking phenyl ring on nearby CH and CF bonds. 19F NMR spectra of 1b and 1c were strongly deshielded compared with those of the ring-opened compounds 3b, 7b, and 7c
- Chang, Yung-Yu,Ho, I-Ting,Ho, Tse-Lok,Chung, Wen-Sheng
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Read Online
- Synthesis and biological evaluation of novel 1,2,4-triazine derivatives bearing carbazole moiety as potent α-glucosidase inhibitors
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A new series of 1,2,4-triazine derivatives bearing carbazole moiety 7a-7p were designed, synthesized, and evaluated for their α-glucosidase inhibitory activity. The majority of the screened compounds displayed potent α-glucosidase inhibitory activity, with IC50 values in the range of 4.27 ± 0.07-47.75 ± 0.25 μM as compared to the standard drug acarbose. Among the series, compound 7k represented the most potent α-glucosidase inhibitory activity with IC50 values of 4.27 ± 0.07 μM. Kinetic analysis revealed that compound 7k is a non-competitive inhibitor with a Ki of 4.43 μM. Furthermore, the binding interactions of compound 7k with α-glucosidase was confirmed through molecular docking. This study showed these 1,2,4-triazine derivatives bearing carbazole moiety as a new class of α-glucosidase inhibitors.
- Wang, Guangcheng,Wang, Jing,He, Dianxiong,Li, Xin,Li, Juan,Peng, Zhiyun
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Read Online
- Zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source
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The zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source and zinc as reductant was successfully conducted. The presented method provides a low-cost, environmentally friendly and practical preparation of α-aryl amino esters, α-hydroxyketones and phenylethylenes. By using D2O as deuterium source, the corresponding products were obtained in high efficiency with excellent deuterium incorporation rate, which gives a cheap and safe tool for access to valuable deuterium-labelled compounds. This journal is
- Shen, Guoli,Liu, Haojie,Chen, Jingchao,He, Zhenxiu,Zhou, Yongyun,Wang, Lin,Luo, Yang,Su, Zhimin,Fan, Baomin
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supporting information
p. 3601 - 3610
(2021/05/04)
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- COMPOUNDS AND USES THEREOF IN THE TREATMENT OF CANCERS AND OTHER MEDICAL CONDITIONS
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There are provided compounds, their preparation and their use in the treatment of medical conditions including cancers and immune disorders.
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Paragraph 0101; 0103; 0109; 00128
(2017/02/09)
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- Base-Free Asymmetric Transfer Hydrogenation of 1,2-Di- and Monoketones Catalyzed by a (NH)2P2-Macrocyclic Iron(II) Hydride
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The hydride isonitrile complex [FeH(CNCEt3)(1 a)]BF4 (2) containing a chiral P2(NH)2 macrocycle (1 a), in the presence of 2-propanol as hydrogen donor, catalyzes the base-free asymmetric transfer hydrogenation (ATH) of prostereogenic ketones to alcohols and the hemihydrogenation of benzils to benzoins, which contain a base-labile stereocenter. Benzoins are formed in up to 83 % isolated yield with enantioselectivity reaching 95 % ee. Ketones give the same enantioselectivity observed with the parent catalytic system [Fe(CNCEt3)2(1 a)] (3 a) that operates with added NaOtBu.
- De Luca, Lorena,Mezzetti, Antonio
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supporting information
p. 11949 - 11953
(2017/09/20)
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- Chemoselective and repetitive intermolecular cross-acyloin condensation reactions between a variety of aromatic and aliphatic aldehydes using a robust N-heterocyclic carbene catalyst
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We found that chemoselectivity of the crossed acyloin product is controlled by the adjustment of the aromatic aldehyde/aliphatic aldehyde ratio. Moreover, we observed the persistent catalytic activity of the homogeneous NHC catalyst in a solution due to N
- Jin, Ming Yu,Kim, Sun Min,Mao, Hui,Ryu, Do Hyun,Song, Choong Eui,Yang, Jung Woon
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supporting information
p. 1547 - 1550
(2014/03/21)
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- N-heterocyclic carbene-catalyzed annulation of α-cyano-1,4-diketones with ynals
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In this paper, the first stereoselective annulation reaction between r-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amounts of a weak carboxylate base, is disclosed. The title transformation proceeds smoothly under mild reaction conditions and generates three contiguous stereogenic centers, one of which is a quaternary acetal carbon. This reaction tolerates a wide variety of electronically distinct substituents on both reaction partners and affords privileged bicyclic scaffolds in 61-90% isolated yields and with up to 20:1 diastereomeric preference.
- Romanov-Michailidis, Fedor,Besnard, Celine,Alexakis, Alexandre
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supporting information
p. 4906 - 4909,4
(2012/12/12)
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- N-heterocyclic carbene-catalyzed annulation of α-cyano-1,4-diketones with ynals
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In this paper, the first stereoselective annulation reaction between r-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amounts of a weak carboxylate base, is disclosed. The title transformation proceeds smoothly under mild reaction conditions and generates three contiguous stereogenic centers, one of which is a quaternary acetal carbon. This reaction tolerates a wide variety of electronically distinct substituents on both reaction partners and affords privileged bicyclic scaffolds in 61-90% isolated yields and with up to 20:1 diastereomeric preference.
- Romanov-Michailidis, Fedor,Besnard, Céline,Alexakis, Alexandre
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supporting information
p. 4906 - 4909
(2013/01/15)
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- One-pot synthesis of quinoxalines starting from aldehydes under metal-free conditions
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An efficient and convenient synthesis of quinoxalines from easily available aldehydes was performed as a one-pot procedure in good to excellent yields under metal-free conditions, via sequential benzoin condensation, aerobic formation of benzils and condensation of the latter with 1,2-diaminobenzenes.
- Hu, Zhong-Yuan,Du, Ding,Tang, Wei-Fang,Lu, Tao
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experimental part
p. 2262 - 2264
(2012/08/07)
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- Highly chemoselective direct crossed aliphatic-aromatic acyloin condensations with triazolium-derived carbene catalysts
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It has been shown for the first time that triazolium precatalysts promote (in the presence of base) highly chemoselective crossed acyloin condensation reactions between aliphatic and ortho-substituted aromatic aldehydes. An o-bromine atom can serve as a temporary directing group to ensure high chemoselectivity (regardless of the nature of the other substituents on the aromatic ring) which then can be conveniently removed. The process is of broad scope and is operationally simple as it does not require the preactivation of any of the coupling partners to ensure selectivtiy. Preliminary data indicate that highly enantioselective variants of the reaction are feasible using chiral precatalysts.
- O'Toole, Sarah E.,Rose, Christopher A.,Gundala, Sivaji,Zeitler, Kirsten,Connon, Stephen J.
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supporting information; experimental part
p. 347 - 357
(2011/04/17)
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- Synthesis and biological studies of silver N-heterocyclic carbene complexes derived from 4,5-diarylimidazole
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A novel class of silver N-heterocyclic carbene complexes (5a-f) were synthesized in high yield by reacting silver(I) oxide with 4,5-diarylimidazolium halides (4a-f). The complexes were characterized using NMR and IR spectroscopy. The structure was confirmed on the example of bromo[1,3-diethyl-4,5-bis(4- fluorophenyl)imidazol-2-ylidene]silver(I) (5c) by crystal structure analysis. The X-ray structure indicated a three-dimensional coordination polymer with a repeating unit consisting of a Ccarben-Ag2-Br 2-Ccarben cluster. Pharmacological investigations revealed that all silver complexes possessed growth inhibitory effects against breast cancer (MCF-7 and MDA-MB-231) as well as colon carcinoma (HT-29) cells. The most active compound 5c was slightly less active against MCF-7 cells, more active against MDA-MB-231 cells and comparable active as cisplatin against HT-29 cells. Further pharmacological investigations were performed with selected compounds on estrogen receptor (ER) binding, DNA intercalation, cyclooxygenase (COX) inhibition and antibacterial activity. The complexes were only marginally active at the DNA, ER and the COX enzymes, so these targets can be excluded to be involved in the mode of action. However, the growth of bacteria was significantly inhibited by 5c and 5f and opens a new application of this complex type.
- Liu, Wukun,Bensdorf, Kerstin,Hagenbach, Adelheid,Abram, Ulrich,Niu, Ben,Mariappan, Aruljothi,Gust, Ronald
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experimental part
p. 5927 - 5934
(2012/01/02)
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- NHC triggered cascade metal-free synthesis of 2,3-diarylated indoles under solvent-free conditions
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A new cascade strategy to the synthesis of 2,3-diarylated indoles via the metal-free reaction of aryl aldehyde and aryl amine triggered by N-heterocyclic carbene (NHC) under solvent-free conditions, has been disclosed. The protocol has the advantages of easy work-up, high yields, wide application scope, and an environmentally benign procedure compared with the reported methods.
- Yao, Changsheng,Wang, Donglin,Lu, Jun,Qin, Bingbin,Zhang, Honghong,Li, Tuanjie,Yu, Chenxia
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supporting information; experimental part
p. 6162 - 6165
(2011/11/30)
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- NHC gold halide complexes derived from 4,5-diarylimidazoles: Synthesis, structural analysis, and pharmacological investigations as potential antitumor agents
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A series of novel neutral NHC gold halide complexes derived from 4,5-diarylimidazoles were synthesized, characterized, and analyzed for biological effects. High growth inhibitory effects in MCF-7 and MDA-MB 231 breast cancer as well as HT-29 colon cancer cell lines depended on the presence of the C4,C5-standing aromatic rings. Methoxy groups at these rings did not change the growth inhibitory properties, while F-substituents in the ortho-position (5d) increased the activity in MCF-7 and MDA-MB 231 cells. The substituents at the nitrogen atoms and the oxidation state of the metal play a subordinate role. The most active bromo[1,3-diethyl-4,5-bis(2-fluorophenyl)-1,3- dihydro-2H-imidazol-2-ylidene]gold(I) (5d) was distinctly more active than cisplatin. All complexes caused thioredoxin reductase (TrxR) inhibition (EC 50 = 374-1505 nM) distinctly lower than auranofin (EC50 = 18.6 nM) excluding this enzyme as main target. Because of the low nuclear content, a participation of DNA interaction on the mode of action is very unlikely. The missing ER binding and the missing correlation of growth inhibition and inactivation of COX enzymes exclude these targets, too. (Figure presented)
- Liu, Wukun,Bensdorf, Kerstin,Proetto, Maria,Abram, Ulrich,Hagenbach, Adelheid,Gust, Ronald
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supporting information; experimental part
p. 8605 - 8615
(2012/02/03)
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- α,β-unsaturated aldehydes as substrates for asymmetric C-C bond forming reactions with thiamin diphosphate (ThDP)-dependent enzymes
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The enzymes benzaldehyde lyase (BAL) from Pseudomonas fluorescens, benzoylformate decarboxylase (BFD) from Pseudomonas putida and pyruvate decarboxylase (PDC) from Saccharomyces cerevisiae provide different C-C bond forming possibilities of α,β-unsaturated aldehydes with aliphatic and aromatic aldehydes. Structure elucidation and determination of the absolute configuration of the products, which were obtained with high regio- and stereoselectivity were carried out. Selective 1,2-reactivity with yields of 75% and >98% ee, for one single isomer (A) were obtained, by choosing the suitable enzyme in combination with the appropriate substrates. By varying enzymes or substrates the regioisomeric hydroxy ketones C, with up to >99% ee, can be obtained. The application of these new chiral building blocks in the synthesis of natural products or biological active substances is considerably facilitated by applying the different ThDP-dependent enzymes as catalysts.
- Cosp, Anabel,Dresen, Carola,Pohl, Martina,Walter, Lydia,Roehr, Caroline,Mueller, Michael
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experimental part
p. 759 - 771
(2009/04/10)
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- Analysis of the inhibition of mammalian carboxylesterases by novel fluorobenzoins and fluorobenzils
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We have synthesized and assessed the ability of symmetrical fluorobenzoins and fluorobenzils to inhibit mammalian carboxylesterases (CE). The majority of the latter were excellent inhibitors of CEs however unexpectedly, the fluorobenzoins were very good enzyme inhibitors. Positive correlations were seen with the charge on the hydroxyl carbon atom, the carbonyl oxygen, and the Hammett constants for the derived Ki values with the fluorobenzoins.
- Hicks, Latorya D.,Hyatt, Janice L.,Moak, Teri,Edwards, Carol C.,Tsurkan, Lyudmila,Wierdl, Monika,Ferreira, Antonio M.,Wadkins, Randy M.,Potter, Philip M.
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p. 3801 - 3817
(2008/02/09)
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- Microwave assisted benzoin condensation using thiamine as catalyst
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α-Hydroxyketones were prepared in appreciable yields at a very high speed, (by the benzoin condensation) under microwave irradiation using a catalytic amount of thiamine hydrochloride, from various aromatic as well as heteroaromatic aldehydes. They can be used as intermediates in NCE synthesis.
- Bag, Seema,Vaze, Vidula V.,Degani, Mariam S.
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p. 267 - 269
(2007/10/03)
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- 1-substituted, 3-carboxylic acid piperidine derivatives
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The present invention relates to therapeutically active azaheterocyclic compounds, a method of preparing the same and to pharmaceutical compositions comprising the compounds. The novel compounds are useful in treating a central nervous system ailment related to the GABA uptake.
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- Catalytic action of azolium salts. VI. Preparation of benzoins and acyloins by condensation of aldehydes catalyzed by azolium salts
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Benzoins 4 (2-hydroxyethanones substituted with aryl groups at the 1- and 2-positions) were prepared by self-condensation of aromatic aldehydes 3 using catalytic amounts of azolium salts 1 and 2 in excellent yields. 1,3-Dimethylbenzimidazolium iodide (2) was an effective catalyst for the preparation of acyloins 6 (2-hydroxyethanones substituted with alkyl groups at the 1- and 2-positions) by self-condensation of aliphatic aldehydes 5. On the other hand, an attempt at the condensation of hexanal (5d) catalyzed by 1,3-dimethylimidazolium iodide (1) failed to yield the acyloin 6d, and instead the aldol-type condensed product 8d was obtained.
- Miyashita,Suzuki,Iwamoto,Higashino
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p. 2633 - 2635
(2007/10/02)
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- Preparation of Some Chromans Substituted at the 3- or 4-Position by an Aryl or Benzyl Group, by the Rhodium-catalysed Intramolecular Nucleophilic Substitution of the Corresponding 3-(2-Fluorophenyl)propanols
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The bis(hexafluorophosphate) salt of the (η5-ethyltetramethylcyclopentadienyl)(η6-benzene)rhodium(III) cation has been used as a catalyst to prepare 3-phenyl-, 3-(4-methoxyphenyl)-, 3-(4-nitrophenyl)-, and 4-benzylchroman by cyclisation of the corresponding substituted 3-(2-fluorophenyl)-propanols in nitromethane-acetone solution. 3-Phenyl-4-hydroxymethylchroman and 3-hydroxymethyl-4-phenylchroman were prepared similarly.An attempt to prepare a bis(chroman) by a double cyclisation with 2-propane-1,3-diol afforded only the monochroman, 4-(2-fluorophenyl)-3-hydroxymethylchroman.Under the conditions of the cyclisation, the erythro and threo forms of 1,4-di(2-fluorophenyl)-butane-2,3-diol afforded only the corresponding 1,3-dioxolanes as the result of the diols reacting with the acetone used as cosolvent.The 1H n.m.r. spectra of the 3-substituted and 3,4-disubstituted chromans which have been prepared are consistent with the heterocyclic ring being in the half-chair conformation (6).
- Houghton, Roy P.,Shervington, Leroy A.
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p. 1872 - 1892
(2007/10/02)
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