ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalytic activity of various salts in the reaction 2,3-epoxypropyl phenyl ether and carbon dioxide under atmospheric pressureNobuhiro Kihara, Nobutaka Hara, Takeshi EndoCite this: J. Org. Chem. 1993, 58, 23, 6198–6202Publication Date (Print):November 1, 1993Publication History Published online1 May 2002Published inissue 1 November 1993https://pubs.acs.org/doi/10.1021/jo00075a011https://doi.org/10.1021/jo00075a011research-articleACS...

Abstract Bis(cyclic Carbonate)s 1 were prepared by the reaction of bis(epoxide)s and atmospheric pressure CO 2 in presence sodium iodide triphenylphosphine as catalysts at 100°C high yield. Polyaddition hexamethylenediamine ( 2a ) or dodecamethylenediamine 2b dimethylsulfoxide N , ‐dimethylacetamide (DMAc) 70 for 24 h afforded corresponding poly(hydroxyurethane)s with M̄ n 20,000–30,000. When ethylenediamine 2c 1,3‐propanediamine 2d was used a diamine, lower molecular weight obtained. The...

Although some reactions on rotaxanes have been reported, the characteristic features of providing unique reaction fields hardly studied, especially as catalyst. In our continuous studies interlocked molecules such and catenanes, we noticed importance structures with high freedom in functionalized materials molecular For catalytic asymmetric benzoin condensations, two optically active possessing thiazolium salt moieties were prepared using binaphthyl group chiral auxiliary. The condensations...

A through-space superexchange mechanism appears to be responsible for charge recombination (CR) following photoexcitation and separation (CS) in rotaxanes containing zinc porphyrin C60 moieties (see picture), as suggested by the low activation energy of this process. Furthermore, charge-separated state is relatively long-lived. Supporting information article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z19881_s.pdf or from author. Please note: The publisher not...

A pseudorotaxane consisting of a 24-membered crown ether and secondary ammonium salt with the hydroxy group at terminus was quantitatively acylated by bulky acid anhydride in presence tributylphosphane as catalyst to afford corresponding rotaxane high yield. Large-scale synthesis without chromatographic separation easily achieved. The resulting excess electrophile trialkylamine. Various N-functionalized rotaxanes were prepared this sequential double-acylation protocol. 1H NMR spectra X-ray...

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTSolid-State End-Capping of Pseudopolyrotaxane Possessing Hydroxy-Terminated Axle Polyrotaxane and Its Application Synthesis a Functionalized Capable Yielding NetworkNobuhiro Kihara, Kazuma Hinoue, Toshikazu TakataView Author Information Department Applied Chemistry, Graduate School Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, 599-8531, Japan, Organic Polymeric Materials, Tokyo Institute...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation of 1,3-Oxathiolane-2-thiones by the Reaction Oxirane and Carbon DisulfideNobuhiro Kihara, Yuichi Nakawaki, Takeshi EndoCite this: J. Org. Chem. 1995, 60, 2, 473–475Publication Date (Print):January 1, 1995Publication History Published online1 May 2002Published inissue 1 January 1995https://pubs.acs.org/doi/10.1021/jo00107a034https://doi.org/10.1021/jo00107a034research-articleACS PublicationsRequest reuse permissionsArticle...

Following the characterization of altohyrtin A (1), altohyrtins B (2) and C (3) 5-desacetylaltohyrtin (4) have been isolated from Okinawan marine sponge Hyrtios altum their plane structures parts relative configurations elucidated. Three congeneric macrolides (2, 3, 4) exhibit extremely potent cytotoxicities similar to those 1 against KB cells with IC50 values 0.02, 0.4 0.3 ng/ml, respectively.

The polyaddition of L-lysine hydrochloride and bifunctional five-membered cyclic carbonate 1 was carried out in DMAc the presence equiv DBU or 2 sodium hydride for 24 h to afford optically active polyurethane bearing hydroxy carboxyl group. L-lysinol also NMP higher molecular weight 3 group quantitative yield. These polyurethanes reacted with cupric acetate, tetrahydroborate, titanium tetraisopropoxide corresponding crosslinked gels immediately. © 1996 John Wiley & Sons, Inc.

Abstract A dynamic covalent approach to disulfide‐containing [2]‐ and [3]rotaxanes is described. Symmetrical dumbbell‐shaped compounds with two secondary ammonium centers a central located disulfide bond were synthesized as components of rotaxanes. The rotaxanes from the dibenzo‐[24]crown‐8 (DB24C8) catalysis by benzenethiol. yields isolated reached about 90 % under optimized conditions. kinetic study on reaction forming [2]rotaxane 2 [3]rotaxane 3 suggested plausible mechanism comprising...

ABSTRACT Carbon fiber–reinforced polymer (CFRP) was prepared from carbon fiber (CF) sheet with a diacylhydrazine‐crosslinked matrix polymer, which is stable to natural stimuli, including heat and oxygen, but rapidly decrosslinks dissolves when treated sodium hypochlorite solution. The CF recovered without damage the CFRP plate solution shearing force. could be used directly prepare next CFRP, again any damage. Because high durability stability are compatible present repetitive use of for practicable.

Abstract Various oxiranes reacted with carbon dioxide at 100 °C using lithium bromide as a catalyst under atmospheric pressure to afford the corresponding five-membered cyclic carbonates quantitatively. The rate of reaction increased bulkiness substituents on oxirane ring was reduced or an electron-withdrawing group introduced ring. stereochemistry and retention without loss optical purity. When substituted phenylethylene were benzylamine, selectivity secondary alcohol ability...

Abstract Acidity of a secondary ammonium group in rotaxane system with crown ether was unusually lowered. N-Acylation the by acid anhydrides or chlorides proceeded slowly presence excess tertiary amine to give N-acylated rotaxanes without salt structure.

Abstract A pseudorotaxane was prepared from dibenzo-24-crown-8 and a dibenzylammonium salt possessing dimethylphenyl hydroxy groups at the both termini. Acylation of by 3,5-dimethylbenzoic anhydride in presence tributylphosphine afforded corresponding rotaxane 90% yield. Various rotaxanes were readily synthesized excellent yields this method.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIncorporation of carbon dioxide into poly(glycidyl methacrylate)Nobuhiro Kihara and Takeshi EndoCite this: Macromolecules 1992, 25, 18, 4824–4825Publication Date (Print):August 1, 1992Publication History Published online1 May 2002Published inissue 1 August 1992https://pubs.acs.org/doi/10.1021/ma00044a053https://doi.org/10.1021/ma00044a053research-articleACS PublicationsRequest reuse permissionsArticle Views512Altmetric-Citations73LEARN ABOUT THESE...

Abstract (2‐Oxo‐1,3‐dioxolan‐4‐yl)methyl methacrylate ( 6 ) was prepared by fixation of CO 2 into glycidyl Systematic name: 2,3‐epoxypropyl. (2) . Pure polymerized spontaneously at room temperature. Radical polymerization (purity 94%) carried out 60°C using 2,2′‐azoisobutyronitrile as an initiator in dimethyl sulfoxide (DMSO) to give the corresponding homopolymer 1 (yield: 99%) which is soluble DMSO and N , ‐dimethylformamide. reacted with butylamien temperature for 24 h polymethacrylate 13...

A rotaxane with a ferrocene moiety at the axle terminus was prepared. The redox potential of decreased by ca. 80 mV when had crown ether wheel capable moving on axle. Thus, stabilization oxidized state is assumed to accompany transposition component toward moiety. [reaction--see text]

Although rotaxane chemists have long believed that the tert-butyl group is bulkier than cavity of dibenzo-24-crown-8-ether (DB24C8), it essentially smaller DB24C8. The (or 4-tert-butylphenyl) can actually function as an end-cap DB24C8-based rotaxanes when intercomponent interaction effectively operative. When such attractive removed, deslippage occurs. [structure: see text]

Abstract Planar chiral rotaxanes were synthesized from crown ether and secondary ammonium salt via trialkylphosphane-catalyzed acylative end-capping. Their optical resolution was achieved by HPLC after neutralization of the group. When optically active trialkylphosphane 2 used as acylation catalyst, rotaxane (4.4% ee) obtained.

Abstract Bifunctional secondary ammonium salt bearing disulfide linkage at the center and bulky group both termini was mixed with dibenzo-24-crown-8. During reversible cleavage of catalyzed by benzenethiol, crown ether entered to afford corresponding [2] [3]rotaxanes.

Three rotaxanes, with axles two zinc porphyrins (ZnPs) at both ends penetrating into a necklace pending C60 moiety, were synthesized varying interlocked structures and axle lengths. The intra-rotaxane photoinduced electron transfer processes between the spatially positioned ZnP in rotaxanes investigated. Charge-separated (CS) states (ZnP*+, C60*-)rotaxane are formed via excited singlet state of (1ZnP*) to moiety solvents such as benzonitrile, THF, toluene. rate constants quantum yields...

The Diels−Alder reaction of various dienophiles such as C60 with a pseudorotaxane having sultine moiety afforded corresponding [2]rotaxanes in moderate yields. introduction porphyrin on the wheel component considerably enhanced efficiency end-capping C60.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and selective molecular recognition of a macrotricyclic receptor having crown ether cyclophane subunits as binding sitesKazuhiko Saigo, Nobuhiro Kihara, Yukihiko Hashimoto, Ru Jang Lin, Hiroshi Fujimura, Yoshihiro Suzuki, Masaki HasegawaCite this: J. Am. Chem. Soc. 1990, 112, 3, 1144–1150Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January...

Basic aspects of step polymerization via reactive intermediate were elucidated for the first time by using a typical example. The polycondensations 2,2-dichloro-1,3-benzodioxole (1) and 4,4'-isopropylidenediphenol (2) with variety feed ratios carried out in refluxing chlorobenzene (2.5 mol/L) 3 h continuous removal hydrogen chloride to give polyorthocarbonate 3. highest molecular weight was obtained when ca. 0.7 equivalent excess 1 used much higher than that calculated according conventional...