- Strategy and design in fluorous phase immobilization: A systematic study of the effect of 'pony tails' (CH2)3(CF2)n-1CF3 on the partition coefficients of benzenoid compounds
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Fluorous solvents commonly exhibit temperature-dependent miscibilities with organic solvents. Thus, catalysts and reagents that have high affinities for fluorous solvents can be used in protocols that combine the advantages of one-phase chemistry (higher temperature) and biphase product separation (lower temperature). The high-yield conversion of benzaldehydes (via Wittig and hydrogenation reactions) to alkylbenzenes with one to three 'pony tails' (CH2)3(CF2)n-1CF3 (n = 6, 8, 10) is described. The toluene-CF3C6F11 partition coefficients show that three pony tails are necessary to achieve a high degree of fluorous phase immobilization. Copyright
- Rocaboy, Christian,Rutherford, Drew,Bennett, Byron L.,Gladysz
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Read Online
- Method for preparing benzenetricarboxaldehyde from Willeberg amide
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The invention discloses a method for preparing benzenetricarboxaldehyde from Willeberg amide. The method comprises the following steps: synthesizing 1, 3, 5-(N-alkyl-N-alkoxy) benzenetricarboxamide, and reducing with a reducing agent to obtain benzenetricarboxaldehyde; the reaction operation is safe, the steps are simple, the product is single, the reaction system treatment is simple, and good conditions are created for industrial large-scale production and commercialization of the product; in the production process, use of highly toxic reagents and precious metal reagents is avoided, pollutant discharge is low, and the method is environmentally friendly and conforms to national industrial policies.
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Paragraph 0032; 0042-0044; 0045-0046
(2021/04/14)
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- A new cobalt(ii) complex nanosheet as an electroactive medium for plasmonic switching on Au nanoparticles
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2D metal-organic complex nanosheets with the merits of high stability and structure tunability are an emerging topic in recent years. To extend the promising ultrathin architectures, a new Co(ii) complex nanosheet (Co-nanosheet) is designed and prepared via a readily operated interface-assisted coordination reaction between the ligand 4,4′′,4′′′-(2,4,6-trimethylbenzene-1,3,5-triyl)tris(2,2′:6′,2′′-terpyridyl) (L) and Co2+ ions. The as-formed Co(ii) complex nanosheet exhibits both a uniform layered structure and good thermostability as proposed, which were verified by various chemical and physical analytical methods. Moreover, it is first utilized as an electroresponsive medium to tune the surface plasmon resonance behavior of Au nanoparticles, expanding the applicable fields of this type of 2D materials. This journal is
- Cheng, Xizhe,Liu, Yurong,Lu, Wenzheng,Wang, Jianfang,Wong, Wai-Yeung
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supporting information
p. 15900 - 15905
(2021/11/30)
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- Readily useable bulk phenoxazine-based covalent organic framework cathode materials with superior kinetics and high redox potentials
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Redox-active covalent organic frameworks (COFs) with dense redox sites are promising electrical energy storage materials with robust architectures, high surface areas, insolubility in electrolytes, and open pores for electrolyte transportation. However, low redox potentials and poor electrical conductivity of pristine COFs often result in low accessibilities of redox-active sites and slow redox kinetics, greatly limiting their practical applications. Herein, we report the design and synthesis of two novel p-type phenoxazine-based COFs (DAPO-COFs) with high redox potentials (~3.6 V vs. Li/Li+) and excellent electrical conductivities. Simply blended with conductive additives (CAs) and binders, pristine bulk DAPO-COFs without pre-composition with CAs or extra exfoliation are readily useable as cathode materials for lithium-ion batteries. Both as-synthesized DAPO-COF powders displayed superior active-site accessibility, ultrafast redox kinetics, and remarkable cycling stability. This work provides new perspectives on the development of readily useable COF-based cathode materials, and contributes to the advancement of eco-friendly and sustainable organic-based energy storage devices. This journal is
- Meng, Zhiying,Zhang, Ying,Dong, Mengqing,Zhang, Yue,Cui, Fengmin,Loh, Teck-Peng,Jin, Yinghua,Zhang, Wei,Yang, Haishen,Du, Ya
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supporting information
p. 10661 - 10665
(2021/05/14)
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- A porous fluorinated organic [4+4] imine cage showing CO2and H2adsorption
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We present the synthesis of a porous, organic [4+4] imine cage containing perfluorinated aromatic panels. Gas adsorption experiments show an uptake of 19.0 wt% CO2(4.2 mmol g-1, 273 K and at 1 bar) and 1.5 wt% H2(7.5 mmol g-1, 77 K and at 1 bar) for the specific surface area of 536 m2g-1of the crystalline material obtained directly from the reaction mixture, combined with an outstanding thermal stability, making it a very interesting porous material suitable for gas adsorption.
- Kunde, Tom,Nieland, Esther,Schr?der, Hendrik V.,Schalley, Christoph A.,Schmidt, Bernd M.
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supporting information
p. 4761 - 4764
(2020/05/13)
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- Design, synthesis, and biological characterization of a new class of symmetrical polyamine-based small molecule CXCR4 antagonists
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CXCR4, a well-studied coreceptor of human immunodeficiency virus type 1 (HIV-1) entry, recognizes its cognate ligand SDF-1α (also named CXCL12) which plays many important roles, including regulating immune cells, controlling hematopoietic stem cells, and directing cancer cells migration. These pleiotropic roles make CXCR4 an attractive target to mitigate human disorders. Here a new class of symmetrical polyamines was designed and synthesized as potential small molecule CXCR4 antagonists. Among them, a representative compound 21 (namely HF50731) showed strong CXCR4 binding affinity (mean IC50 = 19.8 nM) in the CXCR4 competitive binding assay. Furthermore, compound 21 significantly inhibited SDF-1α-induced calcium mobilization and cell migration, and blocked HIV-1 infection via antagonizing CXCR4 coreceptor function. The structure-activity relationship analysis, site-directed mutagenesis, and molecular docking were conducted to further elucidate the binding mode of compound 21, suggesting that compound 21 could primarily occupy the minor subpocket of CXCR4 and partially bind in the major subpocket by interacting with residues W94, D97, D171, and E288. Our studies provide not only new insights for the fragment-based design of small molecule CXCR4 antagonists for clinical applications, but also a new and effective molecular probe for CXCR4-targeting biological studies.
- An, Jing,Fang, Xiong,Huang, Lina S.,Huang, Ziwei,Liang, Boqiang,Meng, Qian,Schooley, Robert T.,Wang, Juan,Xu, Yan,Zhang, Chaozai,Zhang, Huijun,Zhang, Xingquan,Zhu, Siyu
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supporting information
(2020/06/03)
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- The Hydrazine–O2 Redox Couple as a Platform for Organocatalytic Oxidation: Benzo[c]cinnoline-Catalyzed Oxidation of Alkyl Halides to Aldehydes
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An organocatalytic oxidation platform that capitalizes on the capacity of hydrazines to undergo rapid autoxidation to diazenes is described. Commercially available benzo[c]cinnoline is shown to catalyze the oxidation of alkyl halides to aldehydes in a novel mechanistic paradigm involving nucleophilic attack, prototropic shift, and hydrolysis. The hydrolysis and reoxidation events occur readily with only adventitious oxygen and water. A survey of the scope of viable substrates is shown along with mechanistic and computational studies that give insight into this mode of catalysis.
- Stone, Ilana B.,Jermaks, Janis,MacMillan, Samantha N.,Lambert, Tristan H.
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supporting information
p. 12494 - 12498
(2018/09/18)
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- Shape-Persistent [4+4] Imine Cages with a Truncated Tetrahedral Geometry
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The synthesis of shape-persistent organic cage compounds is often based on the usage of multiple dynamic covalent bond formation (such as imines) of readily available precursors. By careful choice of the precursors geometry, the geometry and size of the resulting cage can be accurately designed and indeed a number of different geometries and sizes have been realized to date. Despite of this fact, little is known about the precursors conformational rigidity and steric preorganization of reacting functional groups on the outcome of the reaction. Herein, the influence of conformational rigidity in the precursors on the formation of a [4+4] imine cage with truncated tetrahedral geometry is discussed.
- Lauer, Jochen C.,Zhang, Wen-Shan,Rominger, Frank,Schr?der, Rasmus R.,Mastalerz, Michael
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p. 1816 - 1820
(2018/01/22)
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- MULTICYCLIC PEPTIDES AND METHODS FOR THEIR PREPARATION
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The invention relates to methods for preparing a compound comprising a peptide attached to a molecular scaffold whereby multiple peptide loops are formed, to compounds that can be obtained with such methods and uses thereof.
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Page/Page column 66
(2018/06/30)
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- A Degradable and Recyclable Photothermal Conversion Polymer
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Decomposition and repolymerization of conjugated polymers offer great promise for developing recyclable photothermal conversion materials, which yet remain challenging. Herein, a crosslinked conjugated polymer based on a dynamic covalent bond of Schiff base is developed. This polymer possesses photothermal conversion efficiency as high as 90.4 %. Decomposition of the polymer under specialized conditions is corroborated by various characterizations. The kinetics study is also investigated to understand this degradation process. Furthermore, those decomposed species can be repolymerized back to conjugated polymers which possess the same photothermal conversion efficiency as the pristine polymer. Such a degradable and recyclable photothermal polymer is successfully used as a heat source for photothermal-electrical conversion to generate Seebeck voltage under either near infrared (NIR) irradiation or solar illumination.
- Xu, Xiao-Qi,Wang, Zhen,Li, Ruiting,He, Yonglin,Wang, Yapei
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supporting information
p. 9769 - 9772
(2018/07/25)
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- Method for synthetizing 1,3,5-benzenetricarboxaldehyde from trimesic acid
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The invention provides an experiment method for synthetizing 1,3,5-benzenetricarboxaldehyde by using trimesic acid as raw materials. The experiment conditions are improved; the purification process of the 1,3,5-benzenetricarboxaldehyde is optimized; a 1,3,5-benzenetricarboxaldehyde synthetizing method with mild reaction conditions, low production cost and high product yield is obtained.
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Paragraph 0023
(2018/01/17)
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- Nanoscale covalent organic frameworks as smart carriers for drug delivery
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Two porous covalent organic frameworks (COFs) with good biocompatibility were employed as drug nanocarriers, where three different drugs were loaded for subsequent drug release in vitro. The present work demonstrates that COFs are applicable in drug delivery for therapeutic applications.
- Bai, Linyi,Phua, Soo Zeng Fiona,Lim, Wei Qi,Jana, Avijit,Luo, Zhong,Tham, Huijun Phoebe,Zhao, Lingzhi,Gao, Qiang,Zhao, Yanli
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supporting information
p. 4128 - 4131
(2016/03/19)
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- Synthesis and thermal stability of new polynitrostilbenes
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New polynitrostilbenes were directly synthesised by the Knoevenagel condensation of aromatic aldehydes with nitrotoluenes. The differential scanning calorimetry results demonstrated that the introduction of an amino group and C≤C double bonds could improve the thermal stability.
- Wei, Jianping,Li, Fangmei,Xu, Junhui,Peng, Xinhua
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p. 919 - 925
(2015/06/25)
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- Synthesis of Microporous Nitrogen-Rich Covalent-Organic Framework and Its Application in CO2 Capture
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An imine-based nitrogen-rich covalent-organic framework (COF) was successfully synthesized using two triangular building units under solvothermal reaction condition. The gas adsorption properties of the obtained microporous nitrogen-rich COF were investigated. The results indicated that the activated COF material presented good up take capabilities of CO2 and CH4 at 61.2 and 43.4 cm3·g-1 at 1 atm and 273 K, respectively, showing its application potential in selective gas capture and separation.
- Gao, Qiang,Bai, Linyi,Zhang, Xiaojing,Wang, Peng,Li, Peizhou,Zeng, Yongfei,Zou, Ruqiang,Zhao, Yanli
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- A collection of fullerenes for synthetic access toward oriented charge-transfer cascades in triple-channel photosystems
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The development of synthetic methods to build complex functional systems is a central and current challenge in organic chemistry. This goal is important because supramolecular architectures of highest sophistication account for function in nature, and synthetic organic chemistry, contrary to high standards with small molecules, fails to deliver functional systems of similar complexity. In this report, we introduce a collection of fullerenes that is compatible with the construction of multicomponent charge-transfer cascades and can be placed in triple-channel architectures next to stacks of oligothiophenes and naphthalenediimides. For the creation of this collection, modern fullerene chemistry - methanofullerenes and 1,4-diarylfullerenes - is combined with classical Nierengarten-Diederich-Bingel approaches.
- Bolag, Altan,Lopez-Andarias, Javier,Lascano, Santiago,Soleimanpour, Saeideh,Atienza, Carmen,Sakai, Naomi,Martin, Nazario,Matile, Stefan
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p. 4890 - 4895
(2014/05/20)
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- Polyamine transport inhibitors: Design, synthesis, and combination therapies with difluoromethylornithine
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The development of polyamine transport inhibitors (PTIs), in combination with the polyamine biosynthesis inhibitor difluoromethylornithine (DFMO), provides a method to target cancers with high polyamine requirements. The DFMO+PTI combination therapy results in sustained intracellular polyamine depletion and cell death. A series of substituted benzene derivatives were evaluated for their ability to inhibit the import of spermidine in DFMO-treated Chinese hamster ovary (CHO) and L3.6pl human pancreatic cancer cells. Several design features were discovered which strongly influenced PTI potency, sensitivity to amine oxidases, and cytotoxicity. These included changes in (a) the number of polyamine chains appended to the ring system, (b) the polyamine sequence, (c) the attachment linkage of the polyamine to the aryl core, and (d) the presence of a terminal N-methyl group. Of the series tested, the optimal design was N1,N1′,N1″-(benzene-1,3, 5-triyltris(methylene))tris(N4-(4-(methylamino)butyl)butane-1,4- diamine, 6b, which contained three N-methylhomospermidine motifs. This PTI exhibited decreased sensitivity to amine oxidases and low toxicity as well as high potency (EC50 = 1.4 μM) in inhibiting the uptake of spermidine (1 μM) in DFMO-treated L3.6pl human pancreatic cancer cells.
- Muth, Aaron,Madan, Meenu,Archer, Jennifer Julian,Ocampo, Nicolette,Rodriguez, Luis,Phanstiel, Otto
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p. 348 - 363
(2014/02/14)
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- Constitutional isomers of a C3-symmetric molecule showing different piezochromic behaviours: On-off switching and colour tuning
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The piezochromic behaviours of C3-symmetric molecules with p-bromophenyl side groups connected to a phenyl ring core through cyano-vinylene bridges were studied. Upon grinding, α-BPAN-Br having cyano groups at the α-position to the phenyl ring core exhibited substantial quenching of a bluish green emission (on-off switching) and its constitutional isomer, β-BPAN-Br, showed an emission colour change from bluish green to deep blue (colour tuning). When the molecules were exposed to an organic vapour, the initial emission of each molecule was restored. The powder X-ray diffraction and DSC studies revealed that the as-synthesized and vapour-annealed samples had the same crystalline structures, while the ground samples had amorphous structures. Their structural analogues, α-BPAN-H and β-BPAN-H which had no bromo groups, did not show any piezochromic or vapochromic behaviour. Poly(β-BPAN) consisting of covalently linked β-BPAN units were prepared by Ullmann reaction of β-BPAN-Br. The polymer showed similar luminescence to that of crystalline β-BPAN-Br, but its initial emission was not changed by grinding. the Partner Organisations 2014.
- Lim, Yoonbin,Choi, Insil,Lee, Hyunpyo,Kim, Il Won,Chang, Ji Young
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p. 5963 - 5968
(2014/07/22)
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- Synthesis and mesomorphic properties of new columnar liquid crystal containing 1,3,5-triiminebenzene with pendant 1,3,4-thiadiazole Group
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A novel discotic liquid crystal series based on 1,3,5-benzenetrisazomethine derivatives with three pendant 2-amino-5-(4′-n-alkoxy)phenyl-1,3,4- thiadiazole has been synthesized, which is the first columnar molecules containing 1,3,4-thiadiazole moiety exhibiting a discotic liquid crystal. The molecular structure of compounds was confirmed by FT-IR, 1H-NMR, and mass spectroscopy and elemental analysis. The electron excitation properties of these compounds were investigated by UV-vis absorption spectroscopy. Their liquid crystalline properties were studied by polarizing optical microscopy and differential scanning calorimetry. The formation of a columnar mesophase was found to be dependent on the number of methylene unit in alkoxy side chains.
- Al-Malki, Mustafa K.S.,Hameed, Ayad S.,Al-Dujaili, Ammar H.
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- POLYAMINE TRANSPORT INHIBITORS AS NOVEL THERAPEUTICS
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Novel polyamine transport inhibitors have been synthesized and demonstrated to block the uptake of native polyamines into human cancer cells. A combination therapy of the transport inhibitor and DFMO (a drug which blocks polyamine biosynthesis) provided synergistic activity against a metastatic human colon cancer cell line. The strategy uses polyamine depletion and polyamine metabolism to generate reactive oxygen species within cells as a novel way to treat cancers. This approach may be implemented for widespread use in the treatment of diseases which rely upon polyamine transport activity for proliferation.
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Page/Page column 13; 14-15
(2010/12/31)
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- Readily accessible oxazolidine nitroxyl radicals: Bifunctional cocatalysts for simplified copper based aerobic oxidation
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Using a two-step procedure a range of bifunctional oxazolidine nitroxyl radicals have been prepared. The application of these co-catalysts to the copper-based aerobic oxidation of alcohols was then investigated. From these studies it was found that the parent tetramethyloxazolidine nitroxyl radical L1 was competent for oxidation in the presence of 2,2′-bipyridine, and the bifunctional pyridyl-containing nitroxyl radicals L2 and L3 could be used in the absence of additional coordinating ligands. Following optimization, the scope of this simplified transformation was explored, demonstrating that a range of primary and secondary benzylic alcohols are readily oxidized. In addition, the oxidation of allylic alcohols and hydroquinone can be achieved. Copyright
- Gartshore, Christopher J.,Lupton, David W.
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scheme or table
p. 3321 - 3328
(2011/02/26)
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- 2-Methyl-2-propanol as solvent for o-iodoxybenzoic acid (IBX) oxidation of 1? alcohols to aldehydes
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2-Methyl-2-propanol has been demonstrated to be an effective solvent for IBX oxidation of 1? alcohols to the corresponding aldehydes. IBX has a measurable, but low, solubility in 2-methyl-2-propanol and thus partially avoids the drawbacks inherent in the solubility problems associated with IBX without resorting to less desirable solvents. This may be particularly useful where solubility of the alcohol is also at issue.
- Van Arman, Scott A.
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scheme or table
p. 4693 - 4695
(2011/02/28)
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- Oxidation of alkyl benzenes to corresponding carbonyl compounds with 1,4-dichloro-1,4-diazoniabicyclo [2,2,2] octane bis-chloride in water
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The 1,4-dichloro-1,4-diazoniabicyclo [2,2,2] octane bis-chloride oxidation of various alkylbenzenes gives the corresponding carbonyl compounds in water as solvent.
- Habibzadeh, Setareh,Tajbakhsh, Mahmood
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experimental part
p. 696 - 698
(2010/03/24)
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- A C3-symmetric colorimetric anion sensor bearing hydrazone groups as binding sites
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Tris-hydrazone (1) functioned as a colorimetric chemosensor for a variety of anions such as F-, AcO- and H2PO4-. The anion binding could be easily detected by naked-eye according to color changes. The high binding ability of the receptor 1 to anions was further investigated by UV-vis absorption spectroscopy in DMSO. The results of job plot of the receptor 1 with different anions demonstrated that the stoichiometry of the complex between 1 and F- was 1:1 (1:anion) and the stoichiometry of the other complexes studied was 1:3 (1:anion).
- Shao, Jie,Qiao, Yanhong,Lin, Hai,Lin, Huakuan
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experimental part
p. 1736 - 1740
(2009/03/12)
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- Formyl group as a source of AGIBA effect in mono-, di- and tri- formylo derivatives of benzene
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Experimental geometry of 1,3,5-triformylobenzene and the optimized geometry of mono, meta- and para- diformylo - and 1,3,5-triformylo- benzene derivatives were used for analysis of structural and energetic consequences of angular group induced bond alternation (AGIBA) effect of substituent. The effect is mostly observed by a substantial imbalance of the Kekule structures of the ring in molecules in questions - the cis-type bonds in the ring in respect to CO bond in the formy1 groups are always longer than the trans ones. Energetic differences between molecules with and without AGIBA effects are rather small.
- Fraczak,Krygowski,Cyranski,Korybut-Daszkiewicz
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p. 1999 - 2007
(2008/12/23)
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- A comparison of chloroambucil- and xylene-containing poly amines leads to improved ligands for accessing the polyamine transport system
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Several disubstituted arylene- and chloroambucil-polyamine conjugates were synthesized and evaluated for their ability to target cells via their polyamine transport system (PAT). As compared to the monosubstituted analogues, the disubstituted arylene systems were superior PAT targeting agents. Using a Chinese hamster ovary (CHO) cell line (PAT active) and its CHO-MG mutant (PAT inactive), the series was screened for their PAT targeting ability. The data were expressed as a CHOMG/CHO IC50 ratio. Indeed, the disubstituted systems gave high IC50 ratios (e.g., ratio > 2000), which indicated high selectivity for the PAT. The chloroambucil adducts were less toxic than the corresponding arylmethyl compounds. In this regard, having the proper recognition element (i.e., homospermidine) and cytotoxic "cargo" were deemed paramount for successful drug delivery via the PAT.
- Kaur, Navneet,Delcros, Jean-Guy,Imran, Jon,Khaled, Annette,Chehtane, Mounir,Tschammer, Nuska,Martin, Bénédicte,Phanstiel IV, Otto
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p. 1393 - 1401
(2008/12/20)
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- Synthesis of bis- and trisoxazole derivatives via Suzuki-Miyaura cross-coupling reaction and van Leusen oxazole synthesis
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Both C2- and C3-symmetric oxazole derivatives are synthesized via the Suzuki-Miyaura cross-coupling and van Leusen oxazole synthesis. Here, bis- and triscarboxaldehydes were obtained via the Suzuki-Miyaura cross-coupling and further treated withp-toluenesulfonylmethyl isocyanide (TosMIC) in the presence of potassium carbonate as a base and methanol as a solvent to deliver the corresponding oxazole derivatives. Georg Thieme Verlag Stuttgart.
- Kotha, Sambasivarao,Shah, Vrajesh R.
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p. 3653 - 3658
(2008/09/19)
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- Convenient synthesis of benzene-1,3,5-tricarbaldehyde and congeners
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A convenient synthesis of benzene-1,3,5-tricarbaldehyde was developed as well as benzaldehyde derivatives carrying one or two latent aldehyde groups. The asymmetric derivatives may serve as versatile scaffolds for the synthesis of sectorial dendrimers and multifunctional molecules. Copyright Taylor & Francis Group, LLC.
- Tullberg, Erik,Frejd, Torbjoern
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p. 237 - 245
(2007/10/03)
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- Studies with functionally substituted enamines: The reactivity of enaminals and enamino esters toward naphthoquinone, hydrazonoyl halides, aminoazoles and hippuric acid
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Whereas enamines 1a,b react with naphthoquinone (2) to yield the naphthofuranals 5a,b, enamine ester 1c react with 2 to yield benzoindole derivatives 7. Enamine 1b reacts with hydrazonoyl halides 8 to yield 3,4-disubstituted pyrazoles 12. On the other hand, the enaminal 1a failed to react with 8, while enamine ester 1c afforded hydrazone 16 on treatment with 8. The enamino ester 1b afforded triethyl 1,3,5-benzenetricarboxylates on refluxing in acetic acid. Georg Thieme Verlag Stuttgart.
- Al-Saleh, Balkis,Makhseed, Saad,Hassaneen, Huwaida M. E.,Elnagdi, Mohamed Hilmy
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- Condensation of triformylmethane with adenosine: Novel cyclic adducts derived from 1,3-dicarbonyl compounds
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Condensation of triformylmethane (TFM) with adenosine has been studied in pyridine and aqueous dioxane. One 1:1 (2) and two 2:1 (6 and 7) TFM-adenosine adducts were isolated. The structural assignment of these products by1H and13C NMR and UV spectroscopy and MS spectrometry suggested that the appearance of the 2:1 adducts is connected to a competitive self-condensation of TFM, the stable end product of which is benzene-1,3,5-tricarbaldehyde. The intermediates on the reaction pathway can be reacted with adenosine affording a new procedure for nucleic acid base modification. The mechanisms of formation and the role of intramolecular hydrogen bonding in stabilization of cyclic adenosine adducts are discussed.
- Neuvonen,Koissi,Loennberg
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p. 173 - 177
(2007/10/03)
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- Direct hydrogenation of carboxylic acids to corresponding aldehydes catalyzed by palladium complexes
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A variety of carboxylic acids can be directly hydrogenated into the corresponding aldehydes in high yields by using homogeneous catalysts such as [Pd(PPh3)4] or combination of Pd(OAc)2 with tertiary phosphines in the presence of an excess amount of 2,2-dimethylpropionic anhydride (pivalic anhydride). As a typical example, octanoic acid can be convened into octanal in 99% yield in 3 h at 80 °C under 3.0 MPa of H2 in acetone in the presence of pivalic anhydride and a catalyst system composed of Pd(OAc)2 + 5P(p-tol)3. Such hydrogenation is widely applicable to various aliphatic, aromatic, and heterocyclic carboxylic acids as well as to di- and tribasic carboxylic acids. The process allows the presence of other functional groups such as ketonic carbonyl, nitrile, and ester groups and even internal C=C bonds. Heterogeneous palladium catalyst such as palladium on carbon also showed some catalytic activities.
- Nagayama,Shimizu,Yamamoto
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p. 1803 - 1815
(2007/10/03)
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- Synthesis of Azapolycyclic Systems Based on the Indolizino[3,4-b]quinoline Skeleton - A Diastereoselective Entry to Potential Oligodentate Artificial Receptors
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A convenient diastereoselective synthetic route to the molecular tweezer bis(indolizino[3,4-b]quinolyl)methane 9 and the rigid indolizino[7′,8′:2,3]quinolino[8,7-h]indolizino[8,7-b]quinolines 14, 15 as potential receptor molecules has been developed, involving double imine condensation followed by Lewis acid catalyzed biscyclization of prolinal-derived bis-(imines) 8 and 13, respectively. Whereas the use of SnCl4 leads to the formation of the planar polycycle 15, the corresponding concave product 14 is formed in the presence of EtAlCl2. Both compounds 14, 15, as well as tweezer 9 have been characterized by X-ray crystal-structure analysis. Although tris(imines) 20, 24 derived from 1,3,5-triaminobenzene (18) and tris(4-aminophenyl)amine (23) could be obtained similarly by molecular sieve-catalyzed condensation, the corresponding triscyclization could not be achieved. However, by attaching preformed indolizino[3,4-b]quinoline subunits 25 and 31 to an aromatic core, the bidentate receptors 30, 33 and the tentacle molecule 28 were accessible.
- Temme, Oliver,Dickner, Tim,Laschat, Sabine,Froehlich, Roland,Kotila, Sirpa,Bergander, Klaus
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p. 651 - 659
(2007/10/03)
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- Symmetrical tris(4,6-diamino-5-methylene-2-pyrimidones): New building blocks for self-assembly of hollow spherical supramolecules locked by hydrogen bonds
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Concise synthesis of the tris(pyrimidones) 1a,b is described. Molecular modeling study demonstrated that both the prepared models 1a,b are capable of self-assembling under formation of spherical dimers locked by 18 hydrogen bonds. Extreme insolubility in all common solvents precluded investigation of the self-assembly in solution. Circumstantial evidence in favor of the self-assembly has been provided in the solid and gas phase.
- Alexander, Daniel,Holy, Petr,Fiedler, Pavel,Havlas, Zdenek,Zavada, Jiri
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p. 1464 - 1472
(2007/10/03)
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- Tetrathiafulvalene- and dithiafulvene-substituted mesitylenes, new π-donor molecules with 3-fold symmetry and the formation of an unprecedented new class of electroactive polymers
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Novel π-donor molecules with 3-fold symmetry are built on the 1,3,5-benzene core, substituted with three identical moieties, i.e. -CH=CH(TTF) (8) (TTF = tetrathiafulvalene), -CH2S((TTF)Me3) (9), 1,4-dithiafulven-6-yl (10a,b), and 6-methyl-1,4-dithiafulven-6-yl (11a,b). Cyclic voltammetry experiments demonstrate that oxidation of 10a,b gives rise to the precipitation of an electroactive polymer on the electrode, while 9 can be reversibly oxidized to 93+ and 96+. Electrocrystallization of 9 in the presence of TBA2(Mo6Cl14) affords crystals of (92+)·Mo6Cl142-, whose magnetic properties are investigated by EPR. 10a crystallizes in the monoclinic system, space group P21/c, with a = 3.986(1) A?, b = 21.312(2) A?, c = 20.473(2) A?, β = 94.24(1)°, and Z = 4. 11a crystallizes in the monoclinic system, space group P21/a, with a = 10.919(4) A?, b = 17.175(2) A?, c = 11.481(1) A?, β = 97.86(2)°, and Z = 4. Columns of planar molecules of 10a are exquisitely interlocked to create a dense (dcalcd = 1.61 g cm-3) solid whereas no stacking pattern is observed in the structure of the nonplanar, puckered molecule 11a (dcalcd = 1.44 g cm-3). MO calculations demonstrate that, because of their meta orientation, the three dithiolyidene fragments in 10a and 11a are nearly independent.
- Fourmigué, Marc,Johannsen, Ib,Boubekeur, Kamal,Nelson, Catherine,Batail, Patrick
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p. 3752 - 3759
(2007/10/02)
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- A New Ligand for the Self Assembly of Starburst Coordination Oligomers and Polymers
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The coordination properties of the tridentate ligand 2,2':6',2''-terpyridine (tpy) make it an ideal structural unit to control the assembly of coordination oligomers and polymers, and the new ligand 1,3,5-trisbenzene (ttpy) has been prepared as a building block for the assembly of coordination polymers, the complex 3(ttpy)>6 having been prepared; in the trinuclear complex, the three ruthenium(II) centres are equivalent and oxidise at the same potential.
- Constable, Edwin C.,Thompson, Alexander M. W. Cargill
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p. 617 - 619
(2007/10/02)
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- Conversion of 1,4-Dihydrobenzoic Acids to Polyformylbenzenes under Vilsmeier Reaction Conditions
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1,4-Dihydrobenzoic acids 1a-e are converted by a one-pot reaction to benzene- mono-, di- and tricarboxaldehydes under Vilsmeier reaction conditions in yields ranging from 6 to 65percent.The same methodology also serves to give naphthalene-1,3-dicarboxaldehyde (2f) from 1,4-dihydro-1-naphthoic acid (1f) in 91percent yield.
- Raju, B.,Krishna Rao, G. S.
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p. 197 - 199
(2007/10/02)
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- Vilsmeier-Haack Reaction on Some 3-Buten-2-ols
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Vilsmeier-Haack reaction on 3-buten-2-ols (1b-i) leads to benzene mono-, di- and tricarboxaldehyde (3-8) in yields ranging from 6-26percent.The presence of at least five appropriate participating carbon atoms on the butenol backbone (1b-n) seems to be essential for formylative benzocyclization to occur.
- Sreenivasulu, M.,Krishna Rao, G.S.
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p. 1187 - 1188
(2007/10/02)
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- Formylative Benzoannulation of 2,4-Dienoic Acids under Vilsmeier Reaction Conditions
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Vilsmeier reaction on four known 2,4-dienoic acids (III-VI) furnishes, in yields ranging from 5-45percent the benzoannulated products (VII-XIII).
- Raju, B.,Rao, G. S. Krishna
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p. 175 - 176
(2007/10/02)
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- FORMATION AND POLYMERISATION OF MALONALDEHYDE DURING IRRADIATION OF AQUEOUS SOLUTIONS OF D-GLUCOSE AND LACTOSE WITH ULTRASOUND
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Irradiation with ultrasound, vigorous stirring, or vibration of aqueous solutions of D-glucose and lactose can induce chemical reactions.Malonaldehyde has been identified as one product, and the influence of pH and gas atmosphere on its formation by irradiation with ultrasound has been investigated.Only traces were present in neutral solutions, but it was major product in alkaline solutions.Malonaldehyde is unstable, especially in neutral and acidic solutions, and gives 1,3,5-benzenetricarbaldehyde by 1,2-addition and 1 by 1,4-addition.There is evidence that cyclic structures also exist, the ring closure being brought about by an additional hemiacetal bond.To some extent also, 1,3,5-benzenetricarbaldehyde is incorporated into the oligomers.
- Heusinger, Helmut
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- Synthesis of Some Bicyclophanes
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Bicyclic aromatic compounds, bicyclophanehexanes of general structure A, have been obtained from sixfold Wittig reactions between aromatic bisphosphonium salts and 1,3,5-benzenetricarbaldehyde.Hydrogenation gave bicyclophanes of structure B.The synthesis of bicyclophanes from ylids prepared from the bisphosphonium salts from 1,3- and 1,4-bis(bromomethyl)benzene, 1,3-bis(bromomethyl)-5-bromobenzene, and 2,5-bis(chloromethyl)thiophene is described and the structures of the bicyclophanes discussed.
- Hoegberg, Hans-Erik,Wennerstroem, Olof
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p. 661 - 668
(2007/10/02)
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