- Slow 3MLCT Formation Prior to Isomerization in Ruthenium Carbene Sulfoxide Complexes
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A series of photochromic complexes with general formulas of [Ru(bpy)2(NHC-SR)]2+ and [Ru(bpy)2(NHC-S(O)R)]2+ were prepared and investigated by X-ray crystallography, electrochemistry, and ultrafast transient absorption spectroscopy {where bpy is 2,2′-bipyridine and NHC-SR and NHC-S(O)R are chelating thioether (-SR) and chelating sulfoxide [-S(O)R] N-heterocyclic carbene (NHC) ligands}. The only differences between these complexes are the nature of the R group on the sulfur (Me vs Ph), the identity of the carbene (imidazole vs benzimidazole), and the number of linker atoms in the chelate (CH2 vs C2H4). A total of 13 structures are presented {four [Ru(bpy)2(NHC-SR)]2+ complexes, four [Ru(bpy)2(NHC-S(O)R)]2+ complexes, and five uncomplexed ligands}, and these reveal the expected coordination geometry as predicted from other spectroscopy data. The data do not provide insight into the photochemical reactivity of these compounds. These carbene ligands do impart stability with respect to ground state and excited state ligand substitution reactions. Bulk photolysis reveals that these complexes undergo efficient S → O isomerization, with quantum yields ranging from 0.24 to 0.87. The excited state reaction occurs with a time constant ranging from 570 ps to 1.9 ns. Electrochemical studies reveal an electron transfer-triggered isomerization, and voltammograms are consistent with an ECEC (electrochemical-chemical electrochemical-chemical) reaction mechanism. The carbene facilitates an unusually slow S → O isomerization and an unusally fast O → S isomerization. Temperature studies reveal a small and negative entropy of activation for the O → S isomerization, suggesting an associative transition state in which the sulfoxide simply slides along the S-O bond during isomerization. Ultrafast studies provide evidence of an active role of the carbene in the excited state dynamics of these complexes.
- Breen, Douglas J.,Rack, Jeffrey J.,Schrage, Briana R.,Thapa Magar, Rajani,Ziegler, Christopher J.
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supporting information
p. 16120 - 16127
(2021/11/13)
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- Metal-free visible-light-promoted C(sp3)-H functionalization of aliphatic cyclic ethers using trace O2
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Presented is a light-promoted C-C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidation mechanism which is maintained through the leaching of trace amounts of O2 as sole green oxidant. This journal is
- Blackburn, Bryan G.,Cooke, Maria Victoria,Laulhé, Sébastien,Niu, Ben,Sachidanandan, Krishnakumar
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supporting information
p. 9454 - 9459
(2021/12/09)
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- Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow
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A copper-based photocatalyst, Cu(tmp)(BINAP)BF4, was found to be active in a photoredox Appel-type conversion of alcohols to bromides. The catalyst was identified from a screening of 50 complexes and promoted the transformation of primary and secondary alcohols to their corresponding bromides and carboxylic acids to their anhydrides. The protocol was also amendable and optimized under continuous flow conditions.
- Minozzi, Clémentine,Grenier-Petel, Jean-Christophe,Parisien-Collette, Shawn,Collins, Shawn K.
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supporting information
p. 2730 - 2736
(2018/11/21)
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- Difluoro- and trifluoro diazoalkanes-complementary approaches in batch and flow and their application in cycloaddition reactions
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Herein we report on applications of fluorinated diazoalkanes in cycloaddition reactions, with the emphasis on studying subtle differences between diverse fluorinated diazo compounds. These differences led to two major synthetic protocols in batch and flow that allow the safe and scalable synthesis of fluoroalkyl-, sulfone-substituted pyrazolines.
- Hock, Katharina J.,Mertens, Lucas,Metze, Friederike K.,Schmittmann, Clemens,Koenigs, Rene M.
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supporting information
p. 905 - 909
(2017/08/14)
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- Design, synthesis, and activity evaluation of selective inhibitors of anti-apoptotic Bcl-2 proteins: The effects on the selectivity of the P1 pockets in the active sites
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The anti-apoptotic Bcl-2 proteins are attractive targets for anti-cancer drug development, and the discovery of their selective inhibitors has become a research focus. In this Letter, obvious differences in the P1 pocket of the active site between Bcl-2, Bcl-xL, and Mcl-1 proteins were proposed by the structural comparison of these proteins. As a result, the groups in their inhibitors binding to the P1 pockets may have significant effect on the selectivity for these proteins. Based on this hypothesis, five types of derivatives of the lead compound B-1 were designed, and several highly selective inhibitors of Bcl-xL(E-1) or Mcl-1 proteins (G) were found. The selective inhibitors of Mcl-1 protein found in this Letter provide new structural types for the development of novel antitumor agents.
- Wang, Mingping,Tian, Wei,Wang, Chongqing,Lu, Shihai,Yang, Chao,Wang, Juan,Song, Yunlong,Zhou, Youjun,Zhu, Ju,Li, Zhiyu,Zheng, Canhui
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p. 5207 - 5211
(2016/11/09)
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- Air-Stable NNS (ENENES) Ligands and Their Well-Defined Ruthenium and Iridium Complexes for Molecular Catalysis
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We introduce ENENES, a new family of air-stable and low-cost NNS ligands bearing NH functionalities of the general formula E(CH2)mNH(CH2)nSR, where E is selected from -NC4H8O, -NC4H8, or -N(CH3)2, m and n = 2 and/or 3, and R = Ph, Bn, Me, or SR (part of a thiophenyl fragment). The preparation and characterization of more than 15 examples of well-defined Ru and Ir complexes supported by these ligands that are relevant to bifunctional metal-ligand M/NH molecular catalysis are reported. Reactions of NNS ligands with suitable Ru or Ir precursors afford rich and diverse solid-state and solution chemistries, producing monometallic molecules as well as bimetallics in which the ligand coordinates to the metal via either bidentate (κ2[N,N'] or κ2[N',S]) or tridentate (κ3[N,N',S]) binding modes, depending on the basicity of the sulfur atom, CH2 chain length (m or n parameter), or identity of the transition metal. In the case of Ir, ligands bearing benzyl substituents lead to unprecedented κ4[N,N',S,C]-tetradentate core-structure complexes of the type [IrIIIHCl{κ4(N,N',S,C)-ligand}], resulting from ortho-metalation via C-H oxidative addition. Fourteen of these Ru and Ir complexes have been crystallographically characterized. Air- and moisture-stable complexes of the type trans-[RuIICl2{κ3[N,N',S]-ligand}(L)] (L = PPh3, PCy3, DMSO), and others, effect the selective hydrogenation of methyl trifluoroacetate into the important synthon trifluoroacetaldehyde methyl hemiacetal in basic methanol under relatively mild conditions (35-40 °C, 25 bar H2) with reasonable turnover numbers (i.e., > 1000), whereas the air-stable Ir monohydride complexes [IrIIIHCl{κ4(N,N',S,C)-ligand}] exhibit excellent catalytic activities and high chemoselectivity for the same reaction, reaching turnover numbers of >10 000.
- Dub, Pavel A.,Scott, Brian L.,Gordon, John C.
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supporting information
p. 4464 - 4479
(2015/10/06)
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- POLYDENTATE LIGANDS AND THEIR COMPLEXES FOR MOLECULAR CATALYSIS
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The present invention relates generally to novel achiral and chiral sulfur-, nitrogen- and phosphorus-containing ligands, designated as NNS-type, P(0)NS-type, PNS-type, SNNS-type, SNNP(0)-type, or SNNP-type polydentate ligands and transition metal complexes of these ligands. The catalysts derived from these ligands and transition metal complexes may be used in a wide range of catalytic reactions, including hydrogenation and transfer hydrogenation of unsaturated organic compounds, dehydrogenation of alcohols and boranes, various dehydrogenative couplings, and other catalytic transformations.
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Page/Page column 62
(2016/01/01)
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- Indium(III)-catalyzed one-pot synthesis of alkyl cyanides from carboxylic Acids
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The one-pot preparation of alkyl cyanides from carboxylic acids via alkyl iodides or alkyl bromides, which were in situ generated either by indium(III)-catalyzed reductive iodination or bromination of carboxylic acids, is described. Georg Thieme Verlag Stuttgart New York.
- Moriya, Toshimitsu,Shoji, Kohei,Yoneda, Shinichiro,Ikeda, Reiko,Konakahara, Takeo,Sakai, Norio
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p. 3233 - 3238
(2013/12/04)
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- Synthesis and biological evaluation of berberine-thiophenyl hybrids as multi-functional agents: Inhibition of acetylcholinesterase, butyrylcholinesterase, and Aβ aggregation and antioxidant activity
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A series of berberine-thiophenyl hybrids were designed, synthesised, and evaluated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and β-amyloid (Aβ) aggregation and as antioxidants. Among these hybrids, compounds 4f and 4i, berberine linked with o-methylthiophenyl and o-chlorothiophenyl by a 2-carbon spacer, were observed to be potent inhibitors of AChE, with IC50 values of 0.077 and 0.042 μM, respectively. Of the tested compounds, 4i was also the most potent inhibitor of BuChE, with an IC50 value of 0.662 μM. Kinetic studies and molecular modelling simulations of the AChE-inhibitor complex indicated that a mixed-competitive binding mode existed for these berberine derivatives. The biological studies also demonstrated that these hybrids displayed interesting activities, including Aβ aggregation inhibition and antioxidant properties.
- Su, Tao,Xie, Shishun,Wei, Hui,Yan, Jun,Huang, Ling,Li, Xingshu
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p. 5830 - 5840
(2013/09/12)
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- Indium-catalyzed reductive bromination of carboxylic acids leading to alkyl bromides
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The combination of 1,1,3,3-tetramethyldisiloxane (TMDS) and trimethylbromosilane (Me3SiBr) with a catalytic amount of indium bromide (InBr3) undertook direct bromination of carboxylic acids, which produced the corresponding alkyl bromides in good to excellent yields. The reducing system was tolerant to several functional groups.
- Moriya, Toshimitsu,Yoneda, Shinichiro,Kawana, Keita,Ikeda, Reiko,Konakahara, Takeo,Sakai, Norio
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supporting information
p. 4842 - 4845,4
(2020/09/16)
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- Design, synthesis, and activity evaluation of broad-spectrum small-molecule inhibitors of anti-apoptotic Bcl-2 family proteins: Characteristics of broad-spectrum protein binding and its effects on anti-tumor activity
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On the basis of the comparison of the structure of the Bim BH3: Bcl-x L complex and that of the ABT-737: Bcl-xL complex, a series of class A compounds were designed. These compounds had the basic skeleton of ABT-737 and the h2 residues of Bim BH3. These residues had shown themselves to be relevant to Bim BH3's broad-spectrum binding properties in saturation mutagenesis assays. Unlike ABT-737, which is a selective inhibitor of anti-apoptotic members of the Bcl-2 protein family, the class A compounds showed broad-spectrum binding activity to target proteins similar to those of Bim BH3 peptide. Then class B compounds were synthesized by modifying the structure of the most effective class A compound, A-4. Most of these class B compounds showed better binding affinity to the target proteins than the class A compounds had. They also showed themselves more effective than ABT-737 at inhibiting growth in multiple tumor cell lines known to express Bcl-x L, Bcl-2, and Mcl-1 proteins at high levels. Compounds B-11 and B-12 had the strongest anti-tumor activity of any compounds we produced. This study suggests that it is feasible to design small-molecule inhibitors based on the structure of Bim BH3, which shows broad-spectrum binding to Bcl-xL, Bcl-2, and Mcl-1 proteins. Our results also suggest that the broad-spectrum properties of small-molecule inhibitors binding to target proteins play a critical role in inhibiting the growth of many tumor cells. Finally, our study provides a series of lead compounds that merit further research into anti-cancer therapeutics.
- Zheng, Can-Hui,Yang, Hui,Zhang, Meng,Lu, Shi-Hai,Shi, Duo,Wang, Juan,Chen, Xiu-Hua,Ren, Xiao-Hui,Liu, Jia,Lv, Jia-Guo,Zhu, Ju,Zhou, You-Jun
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supporting information; experimental part
p. 39 - 44
(2012/02/16)
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- Nucleophilic substitution by Grignard reagents on sulfur mustards
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With proper activation of the leaving group, sulfur mustards react with Grignard reagents with neighboring group participation of the sulfur atom. 2,6-Dichloro-9-thiabicyclo[3.3.1]nonane is especially useful in this regard, providing clean reactivity with organomagnesium nucleophiles on a topologically constrained scaffold.
- Converse, Antonella,Saaidi, Pierre-Loic,Sharpless, K. Barry,Finn
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p. 7336 - 7339
(2007/10/03)
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- Efficient synthesis of β-amino bromides
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β-Aminoalcohols were smoothly converted to β-amino bromides using thionyl bromide and DMF, which were easily isolated without any further purification. Participation by the β-amino group in brominations not only enhanced reaction rates but also promoted stereo- and regioselectivities. (C) 2000 Elsevier Science Ltd.
- Nagle, Advait S.,Salvatore, Ralph N.,Chong, Byong-Don,Woon Jung, Kyung
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p. 3011 - 3014
(2007/10/03)
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- BENZOIC ACID COMPOUNDS AND USE THEREOF AS MEDICAMENTS
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Benzoic acid compounds of the formula STR1 wherein each symbol is as defined in the specification, optical isomers thereof and pharmaceutically acceptable salts thereof; pharmaceutical composition comprising this compound and pharmaceutically acceptable additive; and serotonin 4 receptor agonists, gastrointestinal prokinetic agents and therapeutic agents for various gastrointestinal diseases, which comprise this compound as active ingredient. The compounds of the present invention have high and selective affinity for serotonin 4 receptor, and show agonistic effects thereon. Accordingly, they are useful medications for the prophylaxis and treatment of various gastrointestinal diseases, central nervous disorders, cardiac function disorders, urinary diseases, and the like, as well as useful anti-nociceptors for analgesic use which increase threshold of pain.
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- BENZOIC ACID COMPOUNDS AND MEDICINAL USE THEREOF
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A benzoic acid compound of the formula wherein each symbol is as defined in the specification, an optical isomer thereof and a pharmaceutically acceptable salt thereof. A pharmaceutical composition comprising this compound and a pharmaceutically acceptable additive, a serotonin 4 receptor agonist comprising this compound as an active ingredient, a gastrointestinal prokinetic agent and a therapeutic agent for gastrointestinal diseases. The compound of the present invention shows selective and high affinity for serotonin 4 receptors, activates same, is useful as a pharmaceutical agent for the prophylaxis and treatment of gastrointestinal diseases (e.g., reflux esophagitis; gastroesophageal reflux such as that accompanying cystic fibrosis; Barrett syndrome; intestinal pseudoileus; acute or chronic gastritis; gastric or duodenal ulcer; Crohn's disease; non-ulcer dyspepsia; ulcerative colitis; postgastrectomy syndrome; postoperative digestive function failure; delayed gastric emptying caused by gastric neurosis, gastroptosis, diabetes, and the like; gastrointestinal disorders such as indigestion, meteorism, abdominal indefinite complaint, and the like; constipation such as atonic constipation, chronic constipation, and that caused by spinal cord injury, pelvic diaphragm failure and the like; and irritable bowel syndrome), central nervous disorders (e.g., schizophrenia, depression, anxiety, disturbance of memory and dementia), cardiac function disorders (e.g., cardiac failure and myocardial ischemia), urinary diseases (e.g., dysuria caused by urinary obstruction, ureterolith, prostatomegaly, spinal cord injury, pelvic diaphragm failure, etc.), and shows superior absorption.
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- Optically active 3-amino-2H-azirines as synthons for enantiomerically pure α,α-disubstituted α-amino acids: Syntheses of isovaline synthons and a segment of Trichotoxin A-50
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The synthesis of a novel 3-amino-2-methyl-2-[2-(phenylsulfonyl)ethyl]-2H-azirine derivative 12 with a chiral substituent at the amino group is described. Chromatographic separation of the diastereoisomer mixture gave pure diastereoisomers which, after an electrochemical cleavage of the phenylsulfonyl group, yielded the (S)- and (R)-isovalin (Iva) synthons 13a and 13b, respectively. The absolute configuration of the precursor molecule 12b was established by X-ray crystallography. The Iva synthons were successfully used in the synthesis of the C-terminal pentapeptide Z-Leu-Aib-(R)-Iva-Gln-Valol of the peptaibole Trichotoxin A-50 and its epimer.
- Bucher, Christoph B.,Heimgartner, Heinz
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p. 1903 - 1915
(2007/10/03)
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- A PRACTICAL AND CONVENIENT SYNTHESIS OF THE NITROETHYLENE TRANSFER REAGENT, 2-NITROETHYL PHENYL SULFOXIDE
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A safe and practical route to the nitroethylene transfer reagent, 2-nitroethylphenyl sulfoxide, involving sodium nitrite-DMSO, for the introduction of the nitro function, is described.
- Ranganathan, S.,Ranganathan, D.,Singh, S.K.
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p. 2893 - 2894
(2007/10/02)
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- AN IMPROVED, PREPARATIVE ROUTE TO PHENYL VINYL SULFIDE VIA PHASE TRANSFER CATALYSIS
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We wish to report a convenient, preparative method for the formation of phenyl vinyl sulfide under mild conditions and from readily available precursors, using phase transfer techniques.
- Smith, Michael B.
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- N-phenoxy(or thio)hydrocarbon 3,4,5-trihydroxypiperidine derivatives, their use in medicine and in animal nutrition
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The invention relates to 3,4,5-trihydroxypiperidine compound of Formula (I) as methods for the preparation of said compounds. Also included in the invention are compositions containing said piperidine compounds and methods for the use of said piperidine compounds and compositions. The invention further includes veterinary compositions containing said piperidine compounds and their use in animal nutrition. The piperidine compounds of Formula (I) are useful as agents against prediabetes, gastritis, constipation, infections of the gastro-intestinal tract, meteorism, flatulence, caries, arteriosclerosis and hypertension and in particular against diabetes, hyperlipaemia and adiposity, and also in animal nutrition for influencing the meat/fat ratio in favor of the meat content.
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- Dienophilic Properties of Phenyl Vinyl Sulfone and trans-1-(Phenylsulfonyl)-2-(trimethylsilyl)ethylene. Their Utilization as Synthons for Ethylene, 1-Alkenes, Acetylene, and Monosubstituted Alkynes in the Construction of Functionalized Six-Membered Rings via ? Cycloaddition Meth.
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Useful procedures for effecting the indirect capture of ethylene, acetylene, 1-alkenes, and monosubstituted alkynes in Diels-Alder cycloadditions have been developed.In the first sequence, phenyl vinyl sulfone is shown to enter into ? reactions as a moderately reactive dienophile and to do so with very good regioselectivity.The resulting adducts can be directly desulfonated or alkylated prior to such reduction.A wide range of functional groups can be appended in this fashion at a specific locus within the newly formed six-membered ring.When the analogous chemistry is applied to trans-1-(phenylsulfonyl)-2-(trimethylsilyl)ethylene (2), adducts result which undergo ready fluoride ion induced elimination with efficient introduction of a double bond.The use of 2 and its d2 derivative is highlighted by the synthesis of several functionalized dibenzobarrelenes.
- Carr, Richard V. C.,Williams, Richard V.,Paquette, Leo A.
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p. 4976 - 4986
(2007/10/02)
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