- Discotic material hexakis(4-carboxyphenylethynyl)benzene inhibits Escherichia coli growth via the glycolysis pathway
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Discotic materials and nanoparticles are potential carriers of synthetic chemicals to increase the bioavailability. Several planar discotic compounds were prepared with C–C bond formation by the Sonagoshira reaction. Their toxicity was based on their inhi
- Wu, Hsiu-Hui,Chen, Ho-Lun,Hsu, Chih Ying,Yeh, Chih-Ling,Hsu, Hsiu-Fu,Cheng, Chien-Chung
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- Synthesis and characterization of poly(phenylacetylenes) featuring activated ester side groups
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Four monomers based on 4-ethynylbenzoic acid have been synthesized, one of those featuring an activated ester. With the metathesis catalytic system WCl6/Ph4Sn, these acetylenic monomers could successfully be polymerized yielding conjugated polymers with molecular weights of around 10,000 to 15,000 g/mol and molecular weight distributions Mw/M n ≤ 2.1. Also the copolymerization of phenylacetylene or methyl 4-ethynylbenzoate with pentafluorophenyl 4-ethynylbenzoate as reactive unit was conducted. Polymer analogous reactions of the reactive polymers and copolymers with amines have been investigated and it was found that poly(pentafluorophenyl 4-ethynylbenzoate) featured a significant reactivity, such that reactions proceeded quantitatively even with aromatic amines. Moreover the UV-Vis spectra of the activated ester based polymer before and after conversion with aliphatic amines showed a change, indicating an effect on the conjugated backbone of the polymers. Copyright
- Pauly, Anja C.,Theato, Patrick
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- Manganese-Catalyzed ortho-C?H Alkenylation of Aromatic N?H Imidates with Alkynes: Versatile Access to Mono-Alkenylated Aromatic Nitriles
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So far, the direct C?H alkenylation of aromatic nitriles with alkynes has not been achieved. Herein, we discribe the first manganese-catalyzed C?H alkenylation of aromatic N?H imidates to access mono-alkenylated aromatic nitriles. The reaction is accelerated by the presence of a catalytic amount of sodium pivalate. This protocol is also highlighted by the simple catalytic system, good compatibility of functional groups, and excellent mono-/dialkenylation selectivity as well as E/Z stereoselectivity. (Figure presented.).
- Yang, Xiaoxu,Jin, Xiqing,Wang, Congyang
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- Enantioselective Functionalization of Difluorocyclopropenes Catalyzed by Chiral Copper Complexes: Proposal for Chiral gem-Dimethyl and tert-Butyl Analogues
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The highly enantioselective copper/chiral phosphine-catalyzed hydro-, bora-, and carbo-metalations of difluorocyclopropenes with PHMS [H-Si], H-BPin, (BPin)2, and (CH3)2Zn [Zn-Me] are shown to regiodivergently afford highly enantioenriched and functionalized difluorocyclopropanes. These examples can be viewed as the first successful syntheses of "chiral"gem-dimethyl and tert-butyl analogues.
- Sekine, Keisuke,Ushiyama, Aina,Endo, Yu,Mikami, Koichi
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- Tunable electron acceptors based on cyclopenta[hi]aceanthrylenes
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A series of substituted cyclopenta[hi]aceanthrylene derivatives with electron donating (NH2, OCH3), neutral (H), and electron withdrawing (COOH, CF3, CN, NO2) substituents were prepared. A room-temperature Sonogashira cross-coupling reaction between 2,7-dibromocyclopenta[hi]aceanthrylene and an appropriately functionalized phenylene ethynylene precursor was utilized to access the materials that were characterized by Nuclear Magnetic Resonance Spectroscopy (NMR), cyclic voltammetry (CV), and UV-Vis spectroscopy. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were systematically varied when proceeding from electron donating to electron withdrawing substituents. The optical band gap was significantly altered for the most electron donating species, while little change was observed between different electron withdrawing substituents. This study demonstrates the ability to control the frontier orbital energies of this class of cyclopenta-fused polycyclic aromatic hydrocarbon materials through selective substitution.
- Zhu, Xinju,Yuan, Bingxin,Plunkett, Kyle N.
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- Doyle-kirmse reaction using triazoles leading to one-pot multifunctionalization of terminal alkynes
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1-Sulfonyl-1,2,3-triazoles undergo a Doyle-Kirmse reaction upon treatment with allylic sulfides in the presence of a rhodium(II) catalyst to afford α-allyl-α-sulfanylimines. Terminal alkynes are regioselectively multifunctionalized by the introduction of C-N, C-S, and C-C bonds through a one-pot sequence consisting of a [3 + 2] dipolar cycloaddition reaction with azide and subsequent Doyle-Kirmse reaction.
- Miura, Tomoya,Tanaka, Takamasa,Yada, Akira,Murakami, Masahiro
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- From Propargylic Alcohols to Substituted Thiochromenes: Gem-Disubstituent Effect in Intramolecular Alkyne Iodo/hydroarylation
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This work describes the 6-endo-dig cyclization of S-aryl propargyl sulfides to afford 2H-thiochromenes. The substitution at the propargylic position plays a crucial role in allowing intramolecular silver-catalyzed alkyne hydroarylation and N-iodosuccinimide-promoted iodoarylation. Additionally, a PTSA-catalyzed thiolation reaction of propargylic alcohols was developed to synthesize the required tertiary S-aryl propargyl ethers. The applicability of merging these two methods is demonstrated by synthesizing the retinoic acid receptor antagonist AGN194310.
- Velasco, Noelia,Suárez, Anisley,Martínez-Lara, Fernando,Fernández-Rodríguez, Manuel ángel,Sanz, Roberto,Suárez-Pantiga, Samuel
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- Dicarba-closo-dodecaboranes as a pharmacophore. Retinoidal antagonists and potential agonists
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Synthesis and biological evaluation of the first dicarba-closo- dodecaborane (carborane) derivatives of retinoids are described. Their retinoidal activity were examined in terms of the differentiation-inducing ability toward human promyelocytic leukemia HL-60 cells. High retinoidal activity (agonist or antagonist for retinoic acid receptor (RAR)) requires a carboxylic acid moiety and an appropriate hydrophobic group located at a suitable position on the molecule. The 4-carboranyl-substituted compounds (7, 11) showed antagonistic activity but no agonistic activity even in the presence of the potent synergist HX630. On the other hand, the 3-carboranyl- substituted compounds (8, 12) showed potential agonistic activity, but no antagonistic activity. The results indicates that carboranes are applicable as the hydrophobic moiety of biologically active molecules.
- Iijima, Toru,Endo, Yasuyuki,Tsuji, Motonori,Kawachi, Emiko,Kagechika, Hiroyuki,Shudo, Koichi
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- Preparation and Reactions of Mono- and Bis-Pivaloyloxyzinc Acetylides
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Mono-pivaloyloxyzinc acetylide and bis-pivaloyloxyzinc acetylide were selectively prepared from ethynylmagnesium bromide in quantitative yields. These zinc reagents readily underwent Negishi cross-couplings with (hetero)aryl iodides or bromides as well as subsequent Sonogashira cross-couplings. 1,3-Dipolar cycloadditions of these zinc acetylides with benzylic azides produced zincated and bis-zincated triazoles which were trapped with several electrophiles. An opposite regioselectivity compared to the Cu-catalyzed click-reactions was observed.
- Tüllmann, Carl Phillip,Chen, Yi-Hung,Schuster, Robin J.,Knochel, Paul
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- Synthesis and biological evaluation of a novel betulinic acid derivative as an inducer of apoptosis in human colon carcinoma cells (HT-29)
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Abstract A novel family of betulinic acid analogues, carrying a triazole unit at C-3 attached through a linker, was synthesized by the application of azide-alkyne "Click reaction". These were screened for their anticancer activity against different cancer cells and normal human PBMC by MTT assay. Compound 2c [(3S)-3-{2-(4-(hydroxymethyl-1H-1,2,3-triazol-1-yl)acetyloxy}-lup-20(29)-en-28-oic acid] was found as the most potent inhibitor of cell line HT-29 with IC50 value 14.9 μM. Its role as an inducer of apoptosis was investigated in this cell line by Annexin-V/PI binding assay and by following its capability for ROS generation, depolarization of mitochondrial transmembrane potential, activation of caspases, PARP cleavage, nuclear degradation and expression of pro- and anti-apoptotic proteins. It exhibited much higher cytotoxicity than the standard drug 5-fluorouracil but showed negligible cytotoxicity towards normal PBMC. Elevated level of ROS generation, activation of caspase 3 and caspase 9, DNA fragmentation, higher expression of Bax and Bad, lower expression of Bcl2 and Bcl-xl, and increased level of Bax/Bcl-xl ratio identified 2c as a promising inducer of apoptosis that follows a mitochondria dependent pathway. Bio-physical studies indicate that compound 2c acts as a minor groove binder to the DNA.
- Chakraborty, Biswajit,Dutta, Debasmita,Mukherjee, Sanjukta,Das, Supriya,Maiti, Nakul C.,Das, Padma,Chowdhury, Chinmay
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- Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
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The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
- Sattler, Lars E.,Hilt, Gerhard
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supporting information
p. 605 - 608
(2020/12/07)
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- Radical Carbonyl Propargylation by Dual Catalysis
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Carbonyl propargylation has been established as a valuable tool in the realm of carbon–carbon bond forming reactions. The 1,3-enyne moiety has been recognized as an alternative pronucleophile in the above transformation through an ionic mechanism. Herein, we report for the first time, the radical carbonyl propargylation through dual chromium/photoredox catalysis. A library of valuable homopropargylic alcohols bearing all-carbon quaternary centers could be obtained by a catalytic radical three-component coupling of 1,3-enynes, aldehydes and suitable radical precursors (41 examples). This redox-neutral multi-component reaction occurs under very mild conditions and shows high functional group tolerance. Remarkably, bench-stable, non-toxic, and inexpensive CrCl3 could be employed as a chromium source. Preliminary mechanistic investigations suggest a radical-polar crossover mechanism, which offers a complementary and novel approach towards the preparation of valuable synthetic architectures from simple chemicals.
- Huang, Huan-Ming,Bellotti, Peter,Daniliuc, Constantin G.,Glorius, Frank
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supporting information
p. 2464 - 2471
(2020/12/07)
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- Directed polymorphism and mechanofluorochromism of conjugated materials through weak non-covalent control
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Understanding and manipulating crystal polymorphism can provide novel strategies for materials discovery in organic optoelectronics. In this paper, a series of seven ester-terminated three-ring phenylene ethynylenes (PEs) exhibit structure-dependent polymorphism wherein alkyl chain length modulates the propensity to form violet or green fluorescent solid phases, as well as tunable thermal and mechanofluorochromic (MFC) transitions. These compounds harness "soft" non-covalent control to achieve polymorphism: the electronic substituent effect of the ester groups weakens the fluoroarene-arene (ArF-ArH) interactions that typically direct crystal packing of this class of compounds, increasing competitiveness of other interactions. Small structural modifications tip this balance and shift the prevalence of violet- or green-emitting polymorphs. Compounds with short alkyl chain lengths show both violet and various green fluorescent polymorphs, while the violet fluorescent form dominates with alkyl lengths longer than butyl. Further, thermally induced green-to-violet fluorescent crystal-to-crystal transitions occur for single crystals of two derivatives. Finally, the PEs show reversible violet-to-green mechanofluorochromism (MFC), with temperature required for reversion of this MFC decreasing with alkyl chain length. We therefore present this design of directional but weak interactions as a strategy to access polymorphs and tunable stimuli-responsive behavior in solids.
- Sharber, Seth A.,Mann, Arielle,Shih, Kuo-Chih,Mullin, William J.,Nieh, Mu-Ping,Thomas, Samuel W.
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supporting information
p. 8316 - 8324
(2019/07/17)
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- Design, synthesis and anticancer biological evaluation of novel 1,4-diaryl-1,2,3-triazole retinoid analogues of tamibarotene (AM80)
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We report herein the design and synthesis via click chemistry of twelve novel triazole retinoid analogues of tamibarotene (AM80) and the evaluation of their anticancer activities against six cancer cell lines: HL60, K562, 786, HT29, MCF7 and PC3. Among the synthesized compounds, two were more potent than tamibarotene against solid tumor cells, and one of them had similar potency to tamibarotene against HL60 cells. The bioisosteric exchange between the amide group and the 1,2,3-triazole core in the retinoid agent tamibarotene (AM80) reported in this work is a valid strategy for the generation of useful compounds against cancer.
- Aleixo, Mariana A. A.,Garcia, Taís M.,Carvalho, Diego B.,Viana, Luiz H.,Amaral, Marcos S.,Kassab, Najla M.,Cunha, Marilin C.,Pereira, Indiara C.,Guerrero, Palimécio G,Perdomo, Renata T.,Matos, Maria F. C.,Baroni, Adriano C. M.
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p. 109 - 124
(2017/12/08)
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- Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes
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Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes are described. This redox neutral strategy offers an efficient approach to diverse biaryls, vinyl arenes and arylacetylenes. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the in situ formation of Ph3PAuIR (R = aryl, vinyl and alkynyl) species which is crucial for the activation of aryldiazonium salts.
- Akram, Manjur O.,Shinde, Popat S.,Chintawar, Chetan C.,Patil, Nitin T.
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supporting information
p. 2865 - 2869
(2018/05/03)
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- Smectic liquid crystals comprising triazole banana shaped achiral molecules: Synthesis and characterization
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A series of novel liquid crystals containing [1,2,3]-triazole ring were synthesized via “click chemistry.” Their mesomorphic properties and photoelectric properties were investigated and the results indicated that most of compounds exhibited SmA over a wide temperature range (about 50°C). The threshold voltage and the response time of the mixture, T4 and LC 50100 were shorten 0.43?V and 71.5?ms with respect to those of LC 50100 respectively.
- Li, Xiaolian,Zhang, Zongying,Liuya
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p. 395 - 404
(2017/05/26)
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- A copper (II) (II) composite chlorinating agent and copper-based composite chlorinating agent synthesis of 1-chloro-2-aryl acetylene method
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The invention discloses a copper (II) composite chlorinating agent and a method for synthesizing 1-chlorine-2-aryl acetylene based on the copper (II) composite chlorinating agent. The structural formula of the copper (II) composite chlorinating agent is CuCl2.xNaCl.yAl2O3. The chlorinating agent is applicable to chlorination of various substituted aryl acetylene substrates, and is high in universality; the chlorinating agent can directly carry out chlorination reaction on aryl acetylene so as to obtain a 1-chlorine-2-aryl acetylene product; the method is mild in reaction condition, 1-chlorine-2-aryl acetylene can be synthesized with high yield and high selectivity, and the production cost of the 1-chlorine-2-aryl acetylene derivative is greatly lowered.
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Paragraph 0023; 0060; 0061
(2016/11/24)
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- Cleavage of the Carbon–Carbon Triple Bonds of Arylacetylenes for the Synthesis of Arylnitriles without a Metal Catalyst
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Cleavage of the carbon–carbon triple bonds of alkynes was achieved, which led to the synthesis of arylnitriles under transition-metal-free conditions. A vast range of terminal alkyne substrates underwent this reaction to provide the corresponding nitriles in moderate to good yields with good functional group tolerance.
- Lin, Yuanguang,Song, Qiuling
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supporting information
p. 3056 - 3059
(2016/07/12)
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- An oligomeric phenylacetylene compound, preparation method and application thereof
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The invention provides oligomeric phenylene ethynylene (OPE) compounds in formulas (I) and (II) shown in the specification as well as a preparation method and application thereof as photosensitizers in the photo-induced antibacterial process. An OPE molec
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Paragraph 0011; 0020; 0021
(2016/10/10)
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- Topology-guided design and syntheses of highly stable mesoporous porphyrinic zirconium metal-organic frameworks with high surface area
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Through a topology-guided strategy, a series of Zr6-containing isoreticular porphyrinic metal-organic frameworks (MOFs), PCN-228, PCN-229, and PCN-230, with ftw-a topology were synthesized using the extended porphyrinic linkers. The bulky porphyrin ring ligand effectively prevents the network interpenetration which often appears in MOFs with increased linker length. The pore apertures of the structures range from 2.5 to 3.8 nm, and PCN-229 demonstrates the highest porosity and BET surface area among the previously reported Zr-MOFs. Additionally, by changing the relative direction of the terminal phenyl rings, this series replaces a Zr8 cluster with a smaller Zr6 cluster in a topologically identical framework. The high connectivity of the Zr6 cluster yields frameworks with enhanced stability despite high porosity and ultralarge linker. As a representative example, PCN-230, constructed with the most extended porphyrinic linker, shows excellent stability in aqueous solutions with pH values ranging from 0 to 12 and demonstrates one of the highest pH tolerances among all porphyrinic MOFs. This work not only presents a successful example of rational design of MOFs with desired topology, but also provides a strategy for construction of stable mesoporous MOFs.
- Liu, Tian-Fu,Feng, Dawei,Chen, Ying-Pin,Zou, Lanfang,Bosch, Mathieu,Yuan, Shuai,Wei, Zhangwen,Fordham, Stephen,Wang, Kecheng,Zhou, Hong-Cai
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supporting information
p. 413 - 419
(2015/01/30)
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- One-pot synthesis of 1,3-enynes with a CF3 group on the terminal sp2 carbon by an oxidative Sonogashira cross-coupling reaction
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Oxidative Sonogashira cross-coupling reactions of (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane with arylacetylene were achieved using silver fluoride and a palladium catalyst, to afford high yields of various 1,3-enynes with a CF3 group on the terminal sp2 carbon. Silver fluoride promoted C-Si bond dissociation and oxidation of palladium, enabling catalytic use of palladium.
- Ikeda, Akari,Omote, Masaaki,Kusumoto, Kana,Tarui, Atsushi,Sato, Kazuyuki,Ando, Akira
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supporting information
p. 8886 - 8892
(2015/08/24)
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- ANTIMICROBIAL MATERIALS AND METHODS
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The invention provides methods and materials for decontamination of surfaces and fabrics, such as non-woven fabrics, that are contaminated with infestations of microorganisms such as bacteria. Biocidal oligomers having conjugated oligo-(aryl/heteroaryl et
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Page/Page column 47-48
(2013/03/26)
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- STRUCTURE, SYNTHESIS, AND APPLICATIONS FOR OLIGO PHENYLENE ETHYNYLENES (OPES)
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The present disclosure provides novel oligo phenylene ethynylene (OPE) compounds, methods for synthesizing these compounds, and materials and substances incorporating these compounds. The various OPEs show antibacterial, antiviral and antifungal activity.
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Page/Page column 3; 7
(2012/02/02)
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- Porous interpenetrated zirconium-organic frameworks (PIZOFs): A chemically versatile family of metal-organic frameworks
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We present the synthesis and characterization of porous interpenetrated zirconium-organic frameworks (PIZOFs), a new family of metal-organic frameworks obtained from ZrCl4 and the rodlike dicarboxylic acids HO 2C[PE-P(R1,R2)-EP]CO2H that consist of alternating phenylene (P) and ethynylene (E) units. The substituents R 1,R2 were broadly varied (alkyl, Oalkyl, oligo(ethylene glycol)), including postsynthetically addressable substituents (amino, alkyne, furan). The PIZOF structure is highly tolerant towards the variation of R 1 and R2. This together with the modular synthesis of the diacids offers a facile tuning of the chemical environment within the pores. The PIZOF structure was solved from single-crystal X-ray diffraction analysis. The PIZOFs are stable under ambient conditions. PIZOF-2, the PIZOF prepared from HO2C[PE-P(OMe,OMe)-EP]CO2H, served as a prototype to determine thermal stability and porosity. It is stable up to 325°C in air as determined by using thermogravimetry and powder X-ray diffraction. Argon sorption isotherms on PIZOF-2 revealed a Brunauer-Emmett-Teller (BET) surface area of 1250 m2 g-1 and a total pore volume of 0.68 cm3 g-1. Copyright
- Schaate, Andreas,Roy, Pascal,Preusse, Thomas,Lohmeier, Sven Jare,Godt, Adelheid,Behrens, Peter
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supporting information; experimental part
p. 9320 - 9325
(2011/10/02)
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- Silica- and polymer-supported platinum(II) polypyridyl complexes: Synthesis and application in photosensitized oxidation of alkenes
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Square-planar polypyridine platinum(II) complexes have been introduced into a silica/polymer matrix by covalent ligand modification. The photophysical properties of the supported matrices are well retained as their model complexes, and the quantum yields for singlet oxygen (1O2) generation are comparable with that of TPP (tetraphenylporphyrin) under similar conditions. A preliminary application in photosensitized oxidation indicates the silica/polymer-supported matrices are promising, which can be reused without loss of reactivity by a simple filtration. Moreover, the polymer-supported matrix exhibits excellent compatibility in various solvents. The Royal Society of Chemistry 2009.
- Feng, Ke,Peng, Ming-Li,Wang, Deng-Hui,Zhang, Li-Ping,Tung, Chen-Ho,Wu, Li-Zhu
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experimental part
p. 9794 - 9799
(2010/03/04)
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- CHEMICAL FRAMEWORK COMPOSITIONS AND METHODS OF USE
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The disclosure provides metal organic frameworks useful for sensing, gas sorption, microelectronics and switches.
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Page/Page column 32
(2009/12/28)
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- STRUCTURE, SYNTHESIS, AND APPLICATIONS FOR OLIGO PHENYLENE ETHYNYLENES
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Novel compounds generally referred to herein as cationic oligomeric phenylene ethynylenes (OPEs), methods of synthesizing OPEs and various uses for the OPEs are described. The compounds can be synthesized in both symmetrical (S-OPE) and non- symmetrical (N-OPE) forms. Suitable uses include sensor and biocidal applications. Reusable structures incorporating the OPEs that are able to capture and release biological species of interest are also described.
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Page/Page column 5
(2010/01/30)
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- Synthesis of 1,1-diarylethylenes from an α-stannyl β-silylstyrene
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The synthesis of a family of 1,1-diarylethylenes from an α-stannyl β-silylstyrene through a combination of a Stille coupling and a protodesilylation reaction is described. This approach avoids the problematic cine-substitution, which is a well documented side reaction during the palladium-assisted elaboration of α-substituted vinylstannanes to 1,1-disubstituted ethylenes.
- Belema, Makonen,Nguyen, Van N.,Zusi, F. Christopher
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p. 1693 - 1697
(2007/10/03)
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- Compositions and methods for treatment of hyperproliferative diseases
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The invention relates to compositions comprising a retinoid X receptor agonist and an agent capable of activating protein kinase A. The invention also relates to methods of treating hyperproliferative diseases by administering a retinoid X receptor agonis
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- Retinoic acid receptor antagonists as promoters of angiogenesis
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Methods and compositions for treating various disorders by administering a therapeutically effective amount of a retinoic acid receptor antagonist alone or in combination or in conjunction with other therapeutic agents to promote angiogenesis are provided
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- 1-alkoxy and 1-acyloxy substituted cyclohex-1-ene compounds and sulfur and 1-alkoxycarbonyl analogs having retinoid-like biological activity
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Compounds of Formula 1 and of Formula 2 where the symbols have the meaning defined in the specification, have retinoid, retinoid antagonist or retinoid negative hormone like biological activity.
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- Nonpeptide α(v)β3 antagonists. 1. Transformation of a potent, integrin-selective α(IIb)β3 antagonist into a potent α(v)β3 antagonist
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Modification of the potent fibrinogen receptor (α(IIb)β3) antagonist 1 generated compounds with high affinity for the vitronectin receptor α(v)β3. Sequential modification of the basic N-terminus of 1 led to the identification of the
- Duggan,Duong,Fisher,Hamill,Hoffman,Huff,Ihle,Leu,Nagy,Perkins,Rodan,Wesolowski,Whitman,Zartman,Rodan,Hartman
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p. 3736 - 3745
(2007/10/03)
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- ARYL-AND HETEROARYLCYCLOHEXENYL SUBSTITUTED ALKENES HAVING RETINOID AGONIST, ANTAGONIST OR INVERSE AGONIST TYPE BIOLOGICAL ACTIVITY
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Compounds of the formula STR1 wherein the symbols have the meaning defined in the specification, have retinoid-like, retinoid antagonist or retinoid inverse agonist-like biological activity.
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- Chirality assignment of amines and amino alcohols based on circular dichroism induced by helix formation of a stereoregular poly((4- carboxyphenyl)acetylene) through acid-base complexation
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An optically inactive polyacetylene, poly((4-carboxyphenyl)acetylene) (poly-l), exhibits an induced circular dichroism (ICD) in the UV-visible region upon complexation with chiral amines and amino alcohols in DMSO and in the film, the sign of which reflects the stereochemistry including bulkiness, type (primary, secondary, or tertiary), and absolute configuration of the amines. Therefore, the polyacetylene can be used as a novel probe for determining the chirality of amines. Most primary amines and amino alcohols of the same configuration gave the same sign for the induced Cotton effect; however, secondary and/or tertiary amines used in the present study tended to show Cotton effect signs opposite to those of the primary amines and amino alcohols of the same configuration. The magnitude of the ICD likely increases with an increase in the bulkiness of the chiral amines. The complexation dynamics during the formation of the helical structure of poly-1 with chiral amines were investigated on the basis of the spin-spin relaxation behavior and 1H NMR, CD, and optical rotatory dispersion (ORD) titrations. The complex formation of poly-1 with chiral amines such as 1-(l- naphthyl)ethylamine and 2-amino-l-propanol exhibits a positive nonlinear effect between the enantiomeric excess of the chiral amines and amino alcohols and the observed ellipticity of the Cotton effects. The excess enantiomer bound to poly-1 may induce an excess of a single-handed helix (rightor left-handed helix), which may result in a more intense ICD than that expected from the ee of the amine. Moreover, it was found that the coexistence of achiral amines such as l-aminoethanol also induced an excess of one helical sense of poly-1.
- Yashima, Eiji,Matsushima, Teruyuki,Okamoto, Yoshio
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p. 6345 - 6359
(2007/10/03)
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- Novel dienes and dienophiles, VI: On the chemical behavior of Z-ethynyl-1,3-butadiene
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The behavior of 2-ethynyl-1,3-butadiene (1) as the diene component in Diels-Alder additions has been studied using a selection of representative double and triple bond dienophiles. The latter include maleic anhydride (5a), diethyl fumarate (6), benzoquinone (7), methyl acrylate (11), juglone (20), 1-methylcyclopropene (23), dimethyl acetylenedicarboxylate (26), propiolic aldehyde (32), 4-phenyl-1,2,4-triazolin-3,5-dione (35) and diethyl azodicarboxylate (37). [2 + 4] Cycloadducts were formed in all cases in varying yields. The addition is accompanied by thermal dimerization of 1 which leads to 1,4-diethynyl-4-vinyl-1-cyclohexene (43) and 1,6-diethynyl-1,5-cyclooctadiene (39). The mechanism of this dimerization is discussed. In a competition experiment towards maleic anhydride (5a), diene 1 was shown to be ca. five times less reactive than isoprene. VCH Verlagsgesellschaft mbH, 1996.
- Hopf, Henning,Jaeger, Helge,Ernst, Ludger
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p. 815 - 824
(2007/10/03)
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