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Synthesis, structures, molecular docking, cytotoxicity and bioimaging studies of two novel Zn(II) complexes
Two novel compounds [Zn2(Endc)2(bipy)2(H2O)3]·4(H2O)·2(O)(1), [Zn2(Endc)2(phen)2(H2O)]·(O)(2) (bipy Combining double low line 2,2-bipyridine, phen Combining double low line 1,10-phenanthroline, and Endc Combining double low line endo-norbornene-cis-5,6-dicarboxylicacid) have been synthesized and characterized. In this paper abbreviations are FS-DNA (fish sperm DNA), HeLa (human cervix epithelia carcinoma cells), KB (human oral epithelial carcinoma cells), LO2 (human liver cell L-O2), EtBr (ethidium bromide), DMF (Dimethyl Formamide), MTT ([3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium]). The binding of complexes with Fish Sperm DNA were measured by electronic absorption spectra and fluorescence spectroscopy. The ability of these complexes to cleave the pBR322 plasmid DNA or the KB and HeLa DNA extracted in our laboratory was demonstrated by gel electrophoresis assay. The cytotoxic effects of these complexes were examined on two tumor cell lines, HeLa, KBr and one normal cell line LO-2. UV absorption and fluorescence spectra indicate the ability of the complexes bond to DNA with different binding affinity. Gel electrophoresis assay demonstrates which one complex more effective DNA-cleavage activity. The cytotoxic activity of the complexes was tested against two different cancer and one normal cell lines. The two complexes exhibited cytotoxic specificity and significant cancer cell inhibitory rate and lower cytotoxicity toward the normal cell lines. The unique interaction mode with DNA and cancer cells inhibition effect clearly revealed the relationship between the structure and the activity of the novel antitumor agent Zn(II) complexes.
Gao, Enjun,Sun, Na,Zhang, Shaozhong,Ding, Yuqing,Qiu, Xue,Zhan, Yang,Zhu, Mingchang
p. 1 - 11
(2016)
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Synthesis of new polyhedral oligomeric silsesquioxane derivatives as some possible antimicrobial agents
1,3-Dipolar cycloaddition reactions were studied to synthesize Polyhedral oligomeric silsesquioxane (POSS)-based norbornyl imide derivatives containing izoxazoline groups in good yields. And also 1,3-dipolar cycloaddition reactions of azomethine ylides with POSS-based norbornene dipolarophiles for a synthesis of the novel POSS-based norbornane-fused spiro-1,3-indandionolylpyrrolidines are reported. All newly synthesized POSS compounds were structurally characterized by FTIR, 1H, 13C NMR, HRMS and GC/MS analyses.
Ersoy, Elif Basak,Gunkara, Omer Tahir,Ocal, Nuket
p. 257 - 268
(2019)
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Stereo- and regioselective halogenation of norbornenes directed by neighboring group participation
Directing the outcome of electrophilic addition reactions of norbornenes could be a challenging task. We have found that the ionic addition of bromine to dichloro-norbornene 2 is accompanied with the formation of a bromonium cation followed by anchimeric assistance of juxtaposed chlorine to give five-membered chloronium cation, which upon reacting with bromide gives norbornane 4 in >90% yield. At higher temperatures, however, the radical addition of Br2dominates so that dibromo compound 3 appears as the principal reaction product (72%). Stereo- and regioselective rearrangements of norbornenes, reported herein, could be of interest for the syntheses of complex haloalkanes.
Pavlovi?, Radoslav Z.,Border, Sarah E.,Gallucci, Judith,Badji?, Jovica D.
p. 5584 - 5587
(2016)
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An analysis of the structural, thermal and optical characteristics as well as the electrical resistivity of tert-butyldiphenylsilyl substituted poly(norbornene-dicarboximide)s
A sequence of well controlled tert -butyldiphenylsilyl substituted poly(norbornene-dicarboximide)s with ascending molecular weights have been prepared using the Grubbs 1st generation catalyst in anhydrous chloroform. The kinetics of the polymerization was examined using nuclear magnetic resonance spectroscopy and gel permeation chromatography. By decreasing the Grubbs catalyst concentration, the polymer molecular weights increased linearly. The glass transition temperatures and thermal decomposition temperatures initially increased with polymer molecular weight, then reached a plateau. Regardless of molecular weight the polydispersities remained narrow. The polymers exhibited a predominantly trans microstructure and matrix-assisted laser desorption/ionization mass spectrometry was utilized to determine polymer end groups and to calculate the absolute molecular weights. The residual ruthenium content of the polymers was quantified using inductively coupled plasma mass spectrometry and the influence on the resistivity, refractive indices and thin film optical transmittance was evaluated.
Spring, Andrew M.,Maeda, Daisuke,Ozawa, Masaaki,Odoi, Keisuke,Qiu, Feng,Yamamoto, Kazuhiro,Yokoyama, Shiyoshi
p. 189 - 198
(2015)
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Removal of Nerve Agent Simulants from Water Using Light-Responsive Molecular Baskets
We found that molecular baskets 1-3, with amino acids at their rim, undergo photoinduced decarboxylations to give baskets 4-6 forming a solid precipitate in water. Furthermore, organophosphonates 7-9 (OP), akin in size and shape to G-type nerve agents, form inclusion complexes with baskets 1-3 (K = 6-2243 M-1). Light irradiation (300 nm) of an aqueous solution of 1-3?OP led to the formation of precipitate containing an OP compound thereby amounting to a novel strategy for light-induced sequestration of nerve agents or, perhaps, other targeted compounds. Importantly, the stability of basket OP complexes in addition to functional groups at the basket's rim play a role in the efficiency (up to 98%) by which OPs are removed from water.
Border, Sarah E.,Pavlovi?, Radoslav Z.,Zhiquan, Lei,Badji?, Jovica D.
p. 18496 - 18499
(2017)
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ROMP polymer-based antimicrobial films repeatedly chargeable with silver ions
Two norbornene derivatives bearing a pendant pyridyl group were prepared: the 3-(pyridin-2-yl)propyl ester of 5-norbornene-endo-2-carboxylic acid (1) and N-(pyridin-2-ylmethyl)-5-norbornene-endo-2,3-dicarboxyimide (2). Both of these compounds produced high yields of ROMP polymers, poly(1) and poly(2), with the 2nd generation Grubbs catalyst. When Ag+ ions were added to these polymer solutions, the polymer-Ag+ composites, poly(1-Ag) and poly(2-Ag), were formed quantitatively. Poly(2) and poly(2-Ag) produced films from their DMF solutions, and the latter film showed strong antimicrobial properties against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli. Alternatively, when the film of poly(2) was immersed in a solution of Ag+, it was able to trap the ion to give a surface-modified film [Ag/poly(2)]. The antimicrobial efficacy of [Ag/poly(2)] was the same as that of films made of poly(2-Ag), which indicated that the solid-state reaction of the film surfaces toward Ag+ ions in solution was quantitative. When the [Ag/poly(2)] film lost its biocidal effect after repeated use, the Ag + ions could be reloaded by immersing the film in a silver ion solution, which fully restored original activity.
Takano, Shigenaga,Tamegai, Hideyuki,Itoh, Toshihiro,Ogata, Seitaro,Fujimori, Hiroki,Ogawa, Shoujiro,Iida, Takashi,Wakatsuki, Yasuo
p. 195 - 203
(2011)
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Synthesis and Carbonic Anhydrase Inhibition of Novel 2-(4-(Aryl)thiazole-2-yl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione Derivatives
Carbonic anhydrase (CA, EC 4.2.1.1) is a member of the metalloenzyme family. It catalyzes the rapid conversion of carbon dioxide (CO2) and water to bicarbonate (HCO3 ?) and protons (H+) and also plays an important role in biochemical and physiological processes. In this study, a number of novel 2-(4-(aryl)thiazole-2-yl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione derivatives were synthesized and evaluated for their inhibitory characteristics against the human CA isoenzymes I and II (hCA I and hCA II). The structures of the new molecules 8a–i were confirmed by means of IR, 1H NMR, 13C NMR, and elemental analysis. These compounds exhibited excellent inhibitory effects, in the low nanomolar range, with Ki values in the range of 27.07–37.80 nM against hCA I and in the range of 11.80–25.81 nM against hCA II. Our findings suggest that the new isoindolylthiazole derivatives have superior inhibitory effect over acetazolamide (AZA), which is used as clinical CA inhibitor with Ki values of 34.50 and 28.93 nM against the hCA I and hCA II isoenzymes, respectively.
Kocyigit, Umit M.,Aslan, Osman Nuri,Gulcin, Ilhami,Temel, Yusuf,Ceylan, Mustafa
p. 955 - 963
(2016)
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Gas sorption in new fluorine containing polynorbornenes with imide side chain groups
The synthesis of (N-3,5-bis(trifluoromethyl)phenyl-exo-endo-norbornene-5,6-dicarboximide) as well as the ring opening methatesis polymerization (ROMP) of this monomer to yield poly(N-3,5-bis-(trifluoromethyl)phenyl-exo-encdo-norbornene-5,6-dicarboximide) are reported. The glass transition of the polymer is 162°C. Solubility coefficients of different gases (nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, propane, and propylene) in membranes prepared by casting from poly(N-3,5-bis(trifluoromethyl)phenyl-exo-endo-norbornene-5,6-dicarboximide) solutions were measured at several temperatures and pressures. The interpretation of the sorption results by the dual-mode model gives the Henry and Langmuir contributions to the solubility. As usual in glassy membranes, sorption processes are exothermic and the activation energies associated with the Henry and Langmuir parameters are also negative. Gas sorption in the continuous amorphous phase was interpreted in terms of the Flory-Huggins theory obtaining reasonable values for the enthalpic parameter x that accounts for the gas (in liquid form)-polymer interactions. The use of this approach to simulate gas sorption in polymers is discussed.
Tlenkopatchev, Mikhail,Vargas, Joel,Almaraz-Giron, Marco A.,Lopez-Gonzalez, Mar,Riande, Evaristo
p. 2696 - 2703
(2005)
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Modification of polyhedral oligomeric silsesquioxane derivatives with heck reaction as possible new bio-hybrid materials
The regioselective synthesis of Polyhedral oligomeric silsesquioxane (POSS)-based norbornyl imide derivatives through palladium catalyzed Heck coupling reaction was reported on an effective synthetic method to organic–inorganic bio-hybrids serving as advanced materials. The reaction of POSS-based imide derivatives with various aryl iodides catalyzed by palladium acetate in the presence of triethyl amine, as the base, in DMF afforded the products in moderate yields. All new POSS derivatives were structurally characterized by FTIR, 1H, 13C NMR, HRMS and GC/MS analyses.
Tahir Gunkara, Omer
p. 909 - 916
(2019)
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Synthesis, characterization, DNA interaction, apoptosis and molecular docking of Cu(II) and Mn(II) complexes with endo-norbornene-cis-5,6-dicarboxylic acid
Two new novel complexes, [Cu4(Endc)4(phen)4]?7(H2O)?2(O) and [Mn2(Endc)2(phen)2(H2O)2]?(H2O) (phen =1,10-phenanthroline, H2Endc?=?endo-norbornene-cis-5,6-dicarboxylic acid), were synthesized and structurally characterized using IR and 1H NMR spectroscopies, elemental analysis and single-crystal X-ray diffractometry. Their reactivity with calf thymus DNA and HeLa cell DNA was measured using UV absorption and fluorescence spectroscopies. The results indicated that these complexes can bind to DNA with different binding affinity. Gel electrophoresis assay demonstrated the ability of the complexes to cleave pBR322 plasmid DNA. Apoptotic study showed that the complexes exhibit significant cancer cell inhibitory rates. Eventually, the complexes can suitably dock with a special DNA (PDB ID: 1AIO).
Gao, Enjun,Ding, Yuqing,Sun, Na,Zhang, Shaozhong,Qiu, Xue,Zhan, Yang,Zhu, Mingchang
(2017)
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Stereoselective synthesis of polycyclic thiopyrans
The reaction of benzothiete (1) and the bicyclic alkenes 5, 7, 9, or 12 shows a very high π side selectivity (de > 95%) in the formation of the polycyclic thiopyrans 6, 8, 10, 11, 13, and 14.
Meier, Herbert,Schmidt, Michael,Mayer, Axel,Schollmeyer, Dieter,Beile, Bernhard
p. 516 - 520
(2012)
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Hara,M. et al.
p. 95 - 100
(1966)
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Protein phosphatase 2A inhibition and circumvention of cisplatin cross-resistance by novel TCM-platinum anticancer agents containing demethylcantharidin
The structurea€"activity requirement of the PP2A-inhibiting demethylcantharidin for the circumvention of cisplatin cross-resistance demonstrated by the novel TCMa€"Pt compounds is discussed. Novel TCM-platinum compounds [Pt(C8H8O5)(NH 2R)2] 1-5, derived from integrating demethylcantharidin, a modified component from a traditional Chinese medicine (TCM) with a platinum moiety, possess anticancer and protein phosphatase 2A inhibition properties. The compounds are able to circumvent cisplatin resistance by apparently targeting the DNA repair mechanism. Novel isosteric analogues [Pt(C9H 10O4)(NH2R)2] A and B, devoid of PP2A-inhibitory activity, were found to suffer from an enhanced DNA repair and were cross-resistant to cisplatin. The results advocate a well-defined structure-activity requirement associating the PP2A-inhibiting demethylcantharidin with the circumvention of cisplatin cross-resistance demonstrated by TCM-Pt compounds 1-5.
To, Kenneth K.W.,Wang, Xinning,Yu, Chun Wing,Ho, Yee-Ping,Au-Yeung, Steve C.F.
p. 4565 - 4573
(2004)
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Size matters - Strong binding of the terephthalate dianion by thiourea functionalised fused [n]polynorbornane hosts
Remarkably strong binding of the new [5]polynorbornane based host 2b to the terephthalate dianion is based on size complementarity of the preorganised binding cleft with the rigid dicarboxylate guest. The Royal Society of Chemistry.
Lowe, Adam J.,Pfeffer, Frederick M.
p. 1871 - 1873
(2008)
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Diels-Alder adducts of maleic anhydride and dienes: New compounds by crystallization
We have determined the crystal structures of bicyclo[2.2.1]hept-2-ene-endo-cis-5,6-dicarboxylic anhydride, C9H8O3, (I), 1,2,3,4,7,7-hexachlorobicyclo [2.2.1]hept-2-ene-endo-cis-5,6-dicarboxylic anhydride diethyl ether solvate, C9H2Cl6O3·0.16-C4H10O, (II), bicyclo[2.2.1]hept-2-ene-endo-cis-5,6-dicarboxylic acid, C9H10O4, (III), 1,2,3,4,7,7-hexachlorobicyclo [2.2.1]hept-2-ene-endo-cis-5,6-dicarboxylic acid, C9H4Cl6O4, (IVa) and (IVb), and ethyl 1,2,3,4,7, 7-hexachloro-6-carboxybicyclo[2.2.1]hept-2-ene-endo-cis-5-carboxylate monohydrate, C11H8Cl6O4·H2O, (V). Compounds (I) and (II) were prepared by a standard Diels-Alder reaction from maleic anhydride and cyclopentadiene or hexachlorocyclopentadiene, respectively. The crystal-growing processes of these compounds led to surprising results: rapid recrystallization of (I) from diethyl ether and (II) from petroleum ether gave crystals of these compounds, however, crystallization by slow evaporation techniques using common solvents yielded new compounds in which the five-membered heterocycle has been cleaved.
Bolte, Michael,Degen, Alexander,Egert, Ernst
p. 1338 - 1342
(2000)
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Using steric bulk for selective recognition; Blocking the binding site to differentiate guests
Selectivity is demonstrated in a supramolecular host:guest system using a receptor with a non-linear binding site. For the "open" receptor 1 strong binding for both flexible and rigid guests was observed. Receptor 2, with a "blocked" binding site, also bound flexible guests effectively but its affinity for rigid guests was 50 fold lower.
Robson, Ryan N.,Pfeffer, Frederick M.
p. 8719 - 8721
(2016)
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Synthesis of new N-norbornylimide substituted amide derivatives, their reductive Heck and domino Heck reactions
Palladium-catalyzed, regioselective hydroarylation reactions of N-norbornenylimide substituted amides were studied to synthesize pentanamide derivatives containing exo-aryl-substituted norbornyl imide groups in excellent yields. All newly synthesized derivatives have been characterized by FTIR, 1H, 13C NMR, GC/MS and TOF/Qtof analyses.
Albayrak, Fatma,Gunkara, Omer Tahir,Ersoy, Elif Basak,Ocal, Nuket,Kaufmann, Dieter E.
p. 244 - 256
(2017)
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Berson,Mueller
p. 4940
(1961)
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The influence of the framework: An anion-binding study using fused [n]polynorbornanes
A series of bis-thiourea-functionalized [n]polynorbornane hosts (1-6) with increasing size were synthesized and their anion-binding properties were evaluated by using 1HNMR spectroscopic titration and Job's plot analysis. The larger bis-thiourea-[3]polynorbornane scaffolds 4 and 5 bound acetate in a 1:1 (cooperative) arrangement, whereas the corresponding smaller norbornane host 2, identical in preorganization, bound acetate in a 1:2 (independent) arrangement. In contrast, the size of the framework had no influence on the binding of dihydrogenphosphate. These results clearly highlight the subtle influence that the framework itself can have on host-guest interactions. One anion or two? A series of bis-thiourea-functionalized [n]polynorbornane hosts (1-6) with increasing size were synthesized and their anion-binding properties were evaluated by using 1HNMR spectroscopic titration and Job's plot analysis. Our results highlight the subtle influence that the framework itself can have on host-guest interactions.
Long, Benjamin M.,Pfeffer, Frederick M.
p. 1091 - 1098
(2014)
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Application of arylboron difluoride Lewis acid catalysts to the Diels- Alder reaction: Convenient, non-volatile alternatives to boron trifluoride
Comparative studies were carded out on boron trifluoride etherate, phenylboron difluoride and meta-nitrophenylboron difluoride for the Lewis acid catalysed Diels-Alder reaction of cyclopentadiene and a range of standard dienophiles in tetrahydrofuran solution. Phenylboron difluoride showed remarkably similar reactivity in terms of yield and endo to exo selectivity to boron trifluoride, whereas meta-nitrophenylboron difluoride was more reactive than either boron trifluoride or phenylboron difluoride and showed more marked differences in endo: exo ratios. These results contrast to some extent with gas-phase semi-empirical calculations (PM3), which suggest that boron trifluoride and meta-nitrophenylboron difluoride should have similar reactivity; phenylboron difluoride being less reactive. However, since arylboron difluorides are easily prepared, these Lewis acids represent a group of potentially highly tuneable catalysts for Diels-Alder reactions.
De La Torre, Maria Fe,Caballero, M. Cruz,Whiting, Andrew
p. 8547 - 8554
(1999)
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Structural elucidation of daphniacetal A, a new oxa-cage compound isolated from Daphniphyllum macropodum Miq.
A new oxa-cage natural product daphniacetal A (1) was isolated from Daphniphyllum macropodum Miq. Its structure and relative configuration were established based on spectroscopic data and the single-crystal X-ray diffraction crystallography. Compound 1 was also synthesized for determination of its absolute configuration and evaluation of antioxidant effects.
Kong, Ning-Chuan,Zhang, Yu,Gao, Suo,Lu, Yang,Zheng, Qi-Tai,Sun, Quan-Yun,Yang, Fu-Mei,Di, Ying-Tong,Hao, Xiao-Jiang
p. 957 - 959
(2009)
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Hydroarylation reactions of N-acylaminosubstituted tricyclic imides
The palladium-catalysed hydroarylation of unsaturated N-acylamino- substituted tricyclic imides provided a new stereoselective synthesis of exo-aryl(heteroaryl)-substituted tricyclic N-acylamino imides.
Gul, Melek,Kulu, Irem,Ocal, Nuket
p. 345 - 350
(2013)
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Stereoselective synthesis of (3-aminodecahydro-1,4-methanonaphthalen-2-yl) methanols targeted to the C1 domain of protein kinase C
Protein kinase C (PKC) is a widely studied molecular target for the treatment of cancer and other diseases. We have approached the issue of modifying PKC function by targeting the C1 domain in the regulatory region of the enzyme. By using the X-ray crystal structure of the PKCδ C1b domain combined with molecular modeling, we discovered (3-aminodecahydro-1,4- methanonaphthalen-2-yl)methanol as a novel C1 domain ligand. The stereoselective synthesis of this tricyclic γ-amino alcohol was based on two successive Diels-Alder reactions to construct the six continuous stereocenters of the key intermediate.
Kiriazis, Alexandros,Boije Af Genn?s, Gustav,Talman, Virpi,Ekokoski, Elina,Ruotsalainen, Timo,Kyl?nlahti, Irene,Rüffer, Tobias,Wissel, Gloria,Xhaard, Henri,Lang, Heinrich,Tuominen, Raimo K.,Yli-Kauhaluoma, Jari
p. 8665 - 8670
(2011)
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Application of olefin metathesis for the synthesis of constrained β-amino esters from norbornenes
Synthesis of a number of novel, conformationally rigid β-amino esters has been achieved via a tandem olefin metathesis reaction. The starting materials are readily accessible from the Diels-Alder adduct between cyclopentadiene and maleic anhydride. Georg Thieme Verlag Stuttgart.
Nadany, Adam E.,Mckendrick, John E.
p. 2139 - 2141
(2006)
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ROMP polymer supported manganese porphyrins: Influence of C[dbnd]C bonds along polymer chains on catalytic behavior in oxidation of low concentration Fe2+
One unsaturated polymer support was prepared through ring opening metathesis polymerization (ROMP) of norbornene-2,3-dip-toluene sulfonate initiated by Grubbs 2nd initiator and manganese porphyrins were immobilized on polymer through transesterification reaction. To investigate the effect of C[dbnd]C bonds along polymer chains on the catalytic behavior, the obtained polymer supported catalyst (P-PPIXMnCl) was applied in oxidation of low concentration Fe2+ to mimic catalytic behavior of Ceruloplasmin. In the presence of P-PPIXMnCl, the conversion of Fe2+ reaches to 91.92% and 96.46% at 10 °C and 37.5 °C (body temperature), respectively. Compared to manganese porphyrins, P-PPIXMnCl can dramatically increase oxidation rate of Fe2+ and the catalytic kinetic shows that the oxidation reaction changes from second-order to third-order. Upon hydrogenation of ROMP polymer, the oxidation reaction still conforms to the second-order kinetics. Density functional theory (DFT) calculation shows that the C[dbnd]C bonds along polymer chains play an important role in the coordination with Fe2+ in the catalytic microenvironment. The real time morphology of supported catalysts in aqueous environment characterized by Cryo-TEM indicates that hydrogenation can shrink the morphology of polymer-water skeleton. The catalyst could be recycled six times without any significant loss in activity. The liner heterogeneous catalyst is expected to be used as drugs for treating excessive iron accumulation in the human body.
Li, Fanfan,Wang, Xuan,Zhang, Yanwu,Zhao, Huanhuan
(2020)
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Anion recognition using preorganized thiourea functionalized [3]polynorbornane receptors
(Chemical Equation Presented) A new family of [3]polynorbornane frameworks exhibiting conformationally preorganized aromatic thiourea (cleft-like) receptors have been designed and synthesized for anion recognition. These show excellent affinity for the biologically relevant dihydrogenphosphate (H 2PO4-) and dihydrogenpyrophosphate (H 2P2O72-) anions (among others), which are bound in 1:1 and 2:1 (host:anion) ratio, respectively. Moreover, visually striking color changes accompany guest binding, enabling this family to act as colorimetric anion sensors.
Pfeffer, Frederick M.,Gunnlaugsson, Thorfinnur,Jensen, Paul,Kruger, Paul E.
p. 5357 - 5360
(2005)
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Diastereoselective Synthesis of the ABCD Ring System of Rubriflordilactone B
A novel nine-step diastereoselective route to the ABCD ring system of the natural product rubriflordilactone B is reported. Use of an α-substituted butenolide derived from maleic anhydride facilitated a 1,4-conjugate addition to provide a diene. The order in which a ringclosing metathesis and enolate oxidation were performed on this compound dictated the relative stereochemistry of the target. The final product exhibited anisotropic effects during roomerature NMR studies, requiring elevatederature experiments to confirm its identity.
Roth, Hudson G.,Nicewicz, David A.
p. 48 - 51
(2021/11/09)

Sulfa drugs–based Norbornenyl imides and reductive Heck reactions: Synthesis and antimicrobial screening
In the field of our research interest, we designed new sulfa drugs–substituted norbornyl imides as prospective bioactive scaffolds by the reaction of endo-endic anhydride with sulfa drugs followed by reductive Heck reactions of these products. Norbornenyl imides, as starting compounds, and their Heck products were achieved in good yields. Molecular characterization and stereochemistry of the compounds were investigated using Fourier transform infrared, liquid chromatography time-of-flight mass spectrometry, proton nuclear magnetic resonance, carbon 13 attached proton test, H-H correlation spevtroscopy, and nuclear overhauser enhancement spectroscopy experiments. The Heck products of norbornenyl imides showed exo-selectivity. All eight novel synthesized compounds, including two sulfa drugs–based norbornenyl imides and six exo-5-aryl- substituted norbornyl imides, as well as standard sulfonamides, were evaluated for antimicrobial activity against nine microorganisms consisting of Gram-negative bacteria, Gram-positive nonactinobacteria, actinobacteria, and yeast. The most active compound was 3a against actinobacteria. The efficacy of 2 and its derivatives against the studied strains were weaker than 3 and its derivatives, but all the studied samples exhibited antifungal potency.
Bagdatli, Emine,Cil, Elif
(2021/10/27)

Preparation method of exo-Dickson anhydride
The preparation method comprises the following steps: (1) adding a solvent in a reaction container, maleic anhydride, a chiral catalyst D and nitrogen to replace air in a reaction container. (2) At -5 - 5 °C, cyclopentadiene is added dropwise, and the dropping is carried out at a certain temperature. (3) After the completion of the reaction, water was added and quenched. Concentration, crystallization in ethanol and filtration gave exo. The preparation method has the characteristics of high reaction stereoselectivity, high yield, good product quality, simple and convenient process operation, high stability and high safety, and is suitable for industrial mass production.
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Paragraph 0017-0018; 0042-0043; 0046-0049

(2021/10/16)

Synthesis of 4-oxatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione derivatives as lead scaffolds for neuroprotective agents
Neurodegenerative disorders are characterised by progressive loss of neuronal functions. Of the proposed mechanisms, excitotoxicity, mediated by prolonged glutamate activation and calcium overload, is prominent. NGP1-01, a polycyclic cage amine, and tricyclo[6.2.1.02,7]undec-9-ene-3,6-dione have been shown to display calcium-modulating properties. In this study, we synthesised structurally-related 4-oxatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione as the base scaffold, and incorporated various functional moieties through aminolysis, to afford a series of imide derivatives. All final compounds were obtained in yields between 47-97% and their structures were confirmed by NMR, IR and MS. These structurally-related derivatives could potentially act as neuroprotective agents. Additionally, their synthetic versatilities could make them precursors, as lead compounds, to potential pharmacologically-active agents.
Egunlusi, Ayodeji O.,Malan, Sarel F.,Joubert, Jacques
p. 17 - 27
(2020/10/30)

Design and synthesis of c3-symmetric molecules bearing propellane moieties via cyclotrimerization and a ring-closing metathesis sequence
We have developed an efficient synthetic strategy to assemble C3-symmetric molecules containing propellane moieties as end groups and a benzene ring as a central core. The synthesis of these C3-symmetric molecules involves simple starting materials. Our approach to C3-symmetric compounds relies on a Diels–Alder reaction, cyclotrimerization and ring-closing metathesis as key steps.
Kotha, Sambasivarao,Todeti, Saidulu,Aswar, Vikas R.
p. 2537 - 2544
(2018/10/21)

Facile Synthesis of a New Chiral BINOL–Silica Hybrid Catalyst for Asymmetric Diels–Alder and Aza Michael Reactions
Abstract: A novel chiral BINOL–silica hybrid has been successfully prepared by the reaction of (S)-BINOL and SiCl4 following by gel polymerization under atmosphere condition. The synthesized catalyst was characterized by elemental analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Catalytic activity of the chiral BINOL–silica hybrid for diastereo- and enantioselective Diels–Alder and aza Michael reactions has been investigated. Mild reaction conditions, high yields, excellent diastereo- and enantiomeric excess make this powerful and effective catalyst as an attractive option for the synthesis of chiral organic compounds. Graphical Abstract: [Figure not available: see fulltext.]
Saeidian, Hamid,Paghandeh, Hossein,Parvin, Zahra,Mirjafary, Zohreh,Ghaffarzadeh, Mohammad
p. 1366 - 1374
(2018/05/03)

Method for preparing external methylene tetrahydrophthalic anhydride
The invention discloses a method for preparing external methylene tetrahydrophthalic anhydride. The method comprises the following steps that a, maleic anhydride, dicyclopentadiene and an organic solvent are placed in a reaction still and mixed to be uniform, reacting is carried out according to at least two temperature rise steps, and reaction liquid is obtained, wherein the molar ratio of maleic anhydride to dicyclopentadiene is 1:(0.2-10); b, an expected product is separated out of the reaction liquid in the step a, and external methylene tetrahydrophthalic anhydride is obtained. According to the method, the crude product yield (the yield can be increased to 90%) is increased, meanwhile, the chromatographic purity of crude external methylene tetrahydrophthalic anhydride is improved by 85%, the practical yield of external methylene tetrahydrophthalic anhydride is further increased, and an unexpected technical effect is achieved. The method is simple, and convenient to use, low in production cost and suitable for industrial production.
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Paragraph 0088; 0089; 0090; 0091; 0092; 0093

(2017/01/12)

Polyethylene as a Cosolvent and Catalyst Support in Ring-Opening Metathesis Polymerization
Polyethylene oligomers (PEOlig) can be used as cosolvents and sometimes soluble catalyst supports in ring-opening metathesis polymerization (ROMP) reactions. As a catalyst support, this polyolefin serves as an N-heterocyclic carbene ligand for a ROMP catalyst, making it soluble at 70 °C and insoluble at room temperature. As a cosolvent, unfunctionalized PE oligomers facilitate quantitative separation of PEOlig-bound Ru-catalyst residues from polymer products. In these cases, the insolubility of the unfunctionalized polyethylene (Polywax) and its entrapment of the PEOlig-supported Ru residue in the product phase at room temperature afford ROMP products with Ru contamination lower than other procedures that use soluble catalysts. These separations require only physical processes to separate the product and catalyst residues - no additional solvents are necessary. Control experiments suggest that most (ca. 90%) of the Ru leaching that is seen results from Ru byproducts formed in the vinyl ether quenching step and not from the polymerization processes involving the PEOlig-supported Ru complex. (Chemical Equation Presented).
Suriboot, Jakkrit,Hobbs, Christopher E.,Guzman, William,Bazzi, Hassan S.,Bergbreiter, David E.
p. 5511 - 5516
(2015/09/02)

A Diels-Alder/retro-Diels-Alder approach for the enantioselective synthesis of microbial butenolides
Several volatile lactones have been identified from the endophytic fungus Geniculosporium sp. isolated from the rockrose Cistus monspeliensis, commonly known as Montpelier cistus. The fungal volatiles were collected from agar-plate cultures by using a closed-loop stripping apparatus and the headspace extracts were analysed by GC-MS. Structures for these lactones were proposed from their mass spectral data. The suggested structures were verified by synthesis of reference compounds through a Diels-Alder/retro-Diels-Alder approach. This synthetic method was also successfully applied in the synthesis of butenolides that are signalling molecules from streptomycetes. For the enantioselective synthesis of these butenolides a modified route including an enantioselective Diels-Alder reaction was used.
Citron, Christian A.,Wickel, Susanne M.,Schulz, Barbara,Draeger, Siegfried,Dickschat, Jeroen S.
p. 6636 - 6646
(2013/01/15)

Mechanochemical Diels-Alder cycloaddition reactions for straightforward synthesis of endo-norbornene derivatives
Under mechanochemical milling conditions, Diels-Alder cycloaddition of cyclopentadiene with maleic anhydride and maleimide derivatives proceeded very smoothly, affording endo-norbornenes exclusively in quantitative yield. All the transformations were accomplished at room temperature without using any catalyst or organic solvent, thus the workup and purification procedure is very simple. Control experiments on traditional and other tentative conditions were also investigated. Georg Thieme Verlag Stuttgart - New York.
Zhang, Ze,Peng, Zhi-Wei,Hao, Ming-Feng,Gao, Jian-Gang
scheme or table
p. 2895 - 2898
(2011/02/23)

Biodegradable pyridinium ionic liquids: Design, synthesis and evaluation
A range of ionic liquids (ILs) with a pyridinium cation were synthesised and their biodegradability was evaluated using the CO2 Headspace test (ISO 14593). ILs bearing an ester side chain moiety were prepared from either pyridine or nicotinic acid and showed high levels of biodegradation under aerobic conditions and can be classified as 'readily biodegradable'. In contrast, pyridinium ILs with alkyl side chains showed significantly lower levels of biodegradability in the same test. The utility of the biodegradable IL 6c as a reaction solvent for the Diels-Alder reaction was also investigated.
Harjani, Jitendra R.,Singer, Robert D.,Garcia, M. Teresa,Scammells, Peter J.
experimental part
p. 83 - 90
(2010/04/22)

A Tin-tungsten mixed oxide as an efficient heterogeneous catalyst for C-C Bond Bond-Forming reactions
The tin-tungsten mixed oxide prepared by the calcination of the tin-tungsten hydroxide precursor with a Sn/W molar ratio of 2 at 800 °C (SnW2-800) acts as an effective and reusable solid catalyst for C-C bond-forming reactions, such as the cyclization of citronellal, the Diels-Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (TMSCN). Various kinds of structurally diverse aliphatic, aromatic, and unsaturated, heteroatom-containing substrates could be converted into the desired products in high to excellent yields. The observed catalyses for these reactions were truly heterogeneous and the recovered catalyst could be reused several times without an appreciable loss of its high catalytic performance. The Bronsted acid sites generated on the aggregated polytungstate species on SnW2-800 likely play an important role in the C-C bond-forming reactions.
Ogasawara, Yoshiyuki,Uchida, Sayaka,Yamaguchi, Kazuya,Mizuno, Noritaka
experimental part
p. 4343 - 4349
(2009/11/30)

Solvent-free Diels-Alder reactions of in situ generated cyclopentadiene
A solvent-free Diels-Alder reaction was carried out by heating a mixture of dicyclopentadiene and a dienophile. Cyclopentadiene, formed in situ, reacted with the dienophile in a thermodynamically controlled reaction. Besides being solvent-free, the descri
Huertas, David,Florscher, Melinda,Dragojlovic, Veljko
experimental part
p. 91 - 95
(2010/04/22)

Self-immobilizing precatalysts: Norbornene-bridged zirconium ansa-metallocenes
We report here the synthesis of new tethered biscyclopentadienyl and bisindenyl zirconocenes, bearing one unsaturation on the interannular bridge, and their use as self-immobilizing catalysts. They proved to be active catalysts towards ethylene polymerization in solution, with activities comparable to those displayed by commercial rac-Et-(Ind)2ZrCl2. When tested as self-polymerization catalysts under suitable experimental conditions, they gave colored precipitates that, once reactivated with MAO, were significantly active in ethylene polymerization, although lower than those of the corresponding catalytic systems in solution. The molecular weights of the produced polymers were similar to those obtained with the same catalysts in solution, but their distribution resulted to be broader, with values typical of heterogeneous catalytic systems. From 13C NMR studies we had the first spectroscopic evidence of the actual incorporation of a metallocene of this type into a polymeric chain.
Polo, Eleonora,Forlini, Fabrizio,Bertolasi, Valerio,Boccia, Antonella Caterina,Sacchi, Maria Carmela
experimental part
p. 1544 - 1556
(2009/07/30)

Catalyst-free one-pot synthesis of 2,4,6-triaryl-1,4-dihydropyridines in ionic liquid and their catalyzed activity on two simple Diels-Alder reactions
A series of 2,4,6-triaryl-1,4-dihydropyridines bearing a hydroxyl group was synthesized greenly by the cascade aldol/Michael/addition reaction of aromatic aldehyde, acetophenone, and NH4OAc (1:2:excessive) in ionic liquid [BmIm][BF4] without any catalyst. The results of their catalyzed activity on two simple Diels-Alder reactions indicated that this kind of compound containing a poly aryl ring can be used as an effective catalyst on the Diels-Alder reaction. This method, because of its environmental friendliness, simplicity, mild conditions, effectiveness, and lower costs, is suitable for the synthesis of arrays of compounds. Copyright Taylor & Francis Group, LLC.
Wu, Hui,Wan, Yu,Lu,Shen, Yang,Ye,Zhang
p. 666 - 673
(2008/09/16)

Enhanced Diels-Alder reactions: on the role of mineral catalysts and microwave irradiation in ionic liquids as recyclable media
This manuscript explores in detail the combined effect of solid supports or microwave irradiation in ionic liquids on a series of Diels-Alder reactions involving 1,3-cyclopentadiene and numerous dienophiles.
López, Ignacio,Silvero, Guadalupe,Arévalo, María José,Babiano, Reyes,Palacios, Juan?Carlos,Bravo, José Luis
p. 2901 - 2906
(2007/10/03)

An investigation into domino-Heck reactions of N-acylamino-substituted tricyclic imides: Synthesis of new prospective pharmaceuticals
Heck and domino-Heck reactions of unsaturated N-acylamino-substituted tricyclic imides with aryl(heteroaryl) iodides and phenyl- or (trimethylsilyl)acetylene were either carried out in the presence of formate or phenyl- and (trimethylsilyl)acetylene, respectively. The C-C coupling reactions appeared to be completely diastereoselective, giving the corresponding N-acylamino-5-exo-aryl (heteroaryl)- (5a-c, 6a,b), N-(benzoylamino)-5-exo- phenyl-6-exo-[(trimethylsilyl)ethynyl]- (5d), or 5-exo-(4-chlorophenyl)-N-(2,2- dimethylpropanoylamino)-6-exo-(phenylethynyl)bicyclo[2.2.1]heptane-2-endo, 3-endo-dicarboximide (6c) (Schemes 3 and 4).
Bagdatli, Emine,Oecal, Nueket,Kaufmann, Dieter E.
p. 2380 - 2385
(2008/03/29)

METHOD OF SEPARATING STEREOISOMERS OF NORBORNENE, DICARBOXYLIC ACID HAVING NORBORNANE STRUCTURE, OR DERIVATIVE THEREOF
A method of efficiently extracting a high-purity stereoisomer from a mixture comprising the endo isomer and the exo isomer of a dicarboxylic acid having a norbomene or norbomane structure, or a derivative thereof. The present invention relates to a method of separating the endo isomer and the exo isomer of a dicarboxylic acid represented by a general formula (1) or (2) or a derivative thereof, and includes the step of stirring and mixing a mixture comprising mainly the endo isomer of the dicarboxylic acid represented by the general formula (1) or (2) or a derivative thereof, and the exo isomer of the dicarboxylic acid represented by the general formula (1) or (2) or a derivative thereof, with a basic compound and a solvent. (wherein, R1 to R8 represent a hydrogen atom, methyl group, ethyl group, or butyl group), (wherein, R'1 to R'10 represent a hydrogen atom, methyl group, ethyl group, or butyl group)
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Page/Page column 21

(2008/06/13)

Catalysts
A process for performing a catalytic Diels-Alder reaction by reacting a diene with a dienophile in the presence of a heterogeneous catalyst comprising a zeolitic material exchanged or impregnated with ions of a Lewis acidic metal is described. The catalyst, for example, copper-exchanged zeolite Y, may be treated with chiral bis(imine) compounds to direct the chirality of the reaction products. The catalyst can be separated from the reaction mixture and re-used in further Diels Alder reactions.
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Page/Page column 7-8

(2010/02/10)

Structural investigations into the retro-Diels-alder reaction. Experimental and theoretical studies
The manifestations of the retro-Diels Alder reaction in the ground-state structures of a range of cyclopentadiene and cyclohexadiene cycloadducts 9-15 have been investigated by a combination of techniques. These include low-temperature X-ray crystallography, density functional calculations (B3LYP/6-31G(d,p)) on both the ground states and transition states, and the measurement of 13C-13C coupling constants. We have found that the carbon - carbon bonds (labeled bonds a and b), which break in the rDA, are longer in the cycloadducts 9-15 than in their corresponding saturated analogues 9s-15s, which cannot undergo the rDA reaction. The degree of carbon - carbon bond lengthening appears to be related to the reactivity of the cycloadduct, thus the more reactive benzoquinone cycloadducts 5b and 13 have longer carbon - carbon bonds. Those cycloadducts 14 and 15 which are predicted to undergo asynchronous reactions show differing degrees of carbon - carbon bond lengthening, reflecting the differing degrees of bond breaking at the calculated transition states for the rDA.
Birney, David,Lim, Tang Kuan,Koh, Joanne H. P.,Pool, Brett R.,White, Jonathan M.
p. 5091 - 5099
(2007/10/03)

Scandium perfluoroalkanesulfonate-catalyzed Diels-Alder reactions in an organic solvent
Scandium perfluoroalkanesulfonate-catalyzed Diels-Alder reactions proceeded smoothly in dry dichloromethane in the presence of molecular sieves (MS) 5 ?. It was found that water interfered with the reactions, contrary to most rare earth-catalyzed reactions that proceed smoothly in aqueous media. Among scandium perfluoroalkanesulfonates tested, scandium triflate (Sc(OTf)3), scandium pentafluoroethanesulfonate (Sc(OSO2C2F5)3), and scandium nonafluorobutanesulfonate (Sc(OSO2C4F9)3) gave the highest yields and selectivities.
Kobayashi, Shu,Tsuchiya, Takehiro,Komoto, Ichiro,Matsuo, Jun-Ichi
p. 392 - 394
(2007/10/03)

Diels - Alder reactions of epoxybutene derivatives and subsequent synthetic manipulations of the cycloadducts
Diels - Alder reactions between cyclopentadiene, cyclohexadiene, and a number of epoxybutene derivatives are reported. The endo diastereomer from the Diels - Alder reaction of cyclopentadiene with 2,5-dihydrofuran was functionalized by additional oxidative transformations.
Franks, Marion A.,Hyatt, John A.,Welker, Mark E.
p. 514 - 518
(2013/09/07)

Practical and Highly Enantioselective Ring Opening of Cyclic Meso-Anhydrides Mediated by Cinchona Alkaloids
The cinchona alkaloid-mediated opening of prochiral cyclic anhydrides in the presence of methanol leading to optically active hemiesters is described. Very structurally diverse anhydrides are converted into their corresponding methyl monoesters, and either enantiomer can be obtained with up to 99% ee by using quinine or quinidine as directing additive. After the reaction, the alkaloids can be recovered almost quantitatively and reused without loss of enantioselectivity. Additionally, a catalytic protocol which permits the substoichiometric use of quinidine in the presence of easily accessible pentamethylpiperidine (pempidine) is presented.
Bolm, Carsten,Schiffers, Ingo,Dinter, Christian L.,Gerlach, Arne
p. 6984 - 6991
(2007/10/03)

Cope rearrangements versus retro diels-alder reactions
The two isomeric [4+2] cyclo-adducts from two different 1,3-dienes may result from direct cycloadditions as well as from Cope rearrangements (Scheme 1). This general question is tackled by employing two energetically different types of dienes, protonated pyrazolines (1H+, 2H+) or dihydropyridazines (3H+), prepared in situ from their trimers and alicyclic (4-6) or aliphatic (7-9) 1,3-dienes. Depending on structural features and conditions (amount of acid, reaction time), various ratios of the two isomeric [4+2] cycloadducts A and B are obtained; A and B are azo compounds 10, 14,16, 20, 22, 24, 27, 32, 34, 36-39, 41, 42, pyrazolines endo-11, endo-13, endo-15, endo-endo-17, endo-18, endo-19, 21, 23, 25, 26, 28, and hydropyridazines 31, endo-33, endo-35, 40 and 43 (Schemes 3, 4). These results were backed by others from acid-catalyzed isomerizations, trapping experiments, and calculations of the equilibria (ΔΔH) between the isomers (by analogy with the corresponding olefins). A critical discussion reveals: a) Azo compounds 20, 22, 24, 27, 34, 38, and 42 must result from a [4+ + 2] cycloaddition with inverse electron demand, whereas hydropyridazines endo-33, endo-35, 40, and 43 originate from a [4 + 2+] cycloaddition with normal electron demand. b) All isomerizations occur by a [3,3] sigmatropic rearrangement; [4 + 2] cycloreversion is energetically disfavored. c) A clear-cut distinction between the [4+ +2] or [4+2+] cycloaddition reaction routes to the energetically well-balanced systems 10? endo-11 and 12? endo-13 is not possible. d) The two cycloadditions may well favor a nonconcerted reaction through an allylic cationic intermediate which also governs the [3,3] rearrangements (Scheme 8).
Beck, Karin,Hoffman, Petra,Huenig, Siegfried
p. 1588 - 1899
(2007/10/03)

Stereospecificity and concertedness of Retro-Diels-Alder fragmentation in some diester systems upon chemical ionization
Retro-Diels-Alder (RDA) fragmentation of cis- and trans-2,3-diethoxycarbonyl-5,6,7,8-dibenzobicyclo[2.2.2] octanes under isobutane and methane chemical ionization conditions is highly stereospecific, giving rise to protonated diethyl maleate and fumarate, respectively. This behaviour indicates a single-step concerted mechanism, analogous to the ground-state RDA process that occurs in neutral molecules in the condensed phase. The analogous dissociation is partially stereospecific in stereoisomeric endo-, exo- and trans-2,3-diethoxycarbonylbicyclo [2.2.1]heptanes and non-stereospecific in endo-, exo- and trans-2,3-diethoxycarbonyl-5,6-benzobicyclo [2.2.2]octanes, indicating the involvement of a stepwise mechanism in the latter two systems. The different behaviour of the above systems is explained in terms of the energy of the RDA fragmentation. The differentiation and quantitative estimates of protonated diethyl maleate and fumarate were obtained from collision-induced dissociation measurements.
Denekamp,Weisz,Mandelbaum
p. 1028 - 1032
(2007/10/03)

Indium trichloride (InCl3) catalysed Diels-Alder reaction in water
Indium trichloride (InCl3) is found to catalyse the Diels-Alder reaction in water; the catalyst can be easily recovered from water after the reaction is completed and can be reused.
Loh, Teck-Peng,Pei, Jian,Lin, Mei
p. 2315 - 2316
(2007/10/03)