2123-85-5Relevant articles and documents
Triterpenoid-Based Self-Healing Supramolecular Polymer Hydrogels Formed by Host–Guest Interactions
Li, Ying,Li, Jianzuo,Zhao, Xia,Yan, Qiang,Gao, Yuxia,Hao, Jie,Hu, Jun,Ju, Yong
, p. 18435 - 18441 (2016)
Pentacyclic triterpenoids, a class of naturally bioactive products having multiple functional groups, unique chiral centers, rigid skeletons, and good biocompatibility, are ideal building blocks for fabricating versatile supramolecular structures. In this research, the natural pentacyclic triterpenoid glycyrrhetinic acid (GA) was used as a guest molecule for β-cyclodextrin (β-CD) to form a GA/β-CD (1:1) inclusion complex. By means of GA and β-CD pendant groups in N,N′-dimethylacrylamide copolymers, a supramolecular polymer hydrogel can be physically cross-linked by host–guest interactions between GA and β-CD moieties. Moreover, self-healing of this hydrogel was observed and confirmed by step-strain rheological measurements, whereby the maximum storage modulus occurred at a [GA]/[β-CD] molar ratio of 1:1. Additionally, these polymers displayed outstanding biocompatibility. The introduction of a natural pentacyclic triterpenoid into a hydrogel system not only provides a biocompatible guest–host complementary GA/β-CD pair, but also makes this hydrogel an attractive candidate for tissue engineering.
Reversal of regioselectivity and enhancement of rates of nitrile oxide cycloadditions through transient attachment of dipolarophiles to cyclodextrins
Barr, Lorna,Lincoln, Stephen F.,Easton, Christopher J.
, p. 8571 - 8580 (2006)
The reactions of nitrile oxides with monosubstituted dipolarophiles, such as propiolamide, typically afford proportionally 80% or more of the 3,5-disubstituted cycloadducts. By contrast, the reactions of 6 A-deoxy-6A-propynamido-β-cy
Unprecedented Sequence Control and Sequence-Driven Properties in a Series of AB-Alternating Copolymers Consisting Solely of Acrylamide Units
Kametani, Yuki,Ouchi, Makoto,Sawamoto, Mitsuo,Tournilhac, Fran?ois
supporting information, p. 5193 - 5201 (2020/02/18)
Herein, we report a method to synthesize a series of alternating copolymers that consist exclusively of acrylamide units. Crucial to realizing this polymer synthesis is the design of a divinyl monomer that contains acrylate and acrylamide moieties connected by two activated ester bonds. This design, which is based on the reactivity ratio of the embedded vinyl groups, allows a “selective” cyclopolymerization, wherein the intramolecular and intermolecular propagation are repeated alternately under dilute conditions. The addition of an amine to the resulting cyclopolymers afforded two different acryl amide units, i.e., an amine-substituted acryl amide and a 2-hydroxy-ethyl-substituted acryl amide in alternating sequence. Using this method, we could furnish ten types of alternating copolymers; some of these exhibit unique properties in solution and in the bulk, which are different from those of the corresponding random copolymers, and we attributed the differences to the alternating sequence.
Novozym 435-Catalyzed Synthesis of Well-Defined Hyperbranched Aliphatic Poly(β-thioether ester)
Liu, Zi,Wu, Wan-Xia
, (2020/02/18)
A series of new hyperbranched aliphatic poly(β-thioether ester)s were prepared by the enzymatic ring-opening polycondensation of 1,4-oxathiepan-7-one (OTO) and AB2/ABB’ comonomer with acid-labile β-thiopropionate groups. Two kinds of comonomers, methyl 3-((3-hydroxy-2-(hydroxymethyl)propyl)thio)propanoate (HHTP) and methyl 3-((2,3-dihydroxypropyl)thio)propanoate (DHTP), with different primary alcohols and secondary alcohols, were synthesized by thiol–ene click chemistry and thiol-ene Michael addition, respectively. Immobilized lipase B from Candida antarctica (CALB), Novozym 435, was used as the catalyst. The random copolymers were characterized by 1H-NMR, 13C-NMR, GPC, TGA, and DSC. All branched copolyesters had high molecular weights over 15,000 Da with narrow polydispersities in the range of 1.75–2.01 and were amorphous polymers. Their degradation properties under acidic conditions were also studied in vitro. The polymeric nanoparticles of hyperbranched poly(β-thioether ester)s were successfully obtained and showed good oxidation-responsive properties, indicating their potential for biomedical applications.
Kinetic studies of conjugate addition of amines to allenic and acrylic esters and their correlation with antibacterial activities against Staphylococcus aureus
Kiattisewee, Cholpisit,Kaidad, Angkit,Jiarpinitnun, Chutima,Luanphaisarnnont, Torsak
, p. 1059 - 1068 (2018/02/26)
Abstract: Kinetic reactivities of various allenic and acrylic esters in conjugate addition reactions with various amines were investigated. Competition experiments showed that amines reacted selectively with allenic esters, which was also confirmed by quantitative determination of the rate constants. The antibacterial activity against Staphylococcus aureus of allenic and acrylic ester derivatives were also determined. Allenic esters were found to exhibit a higher antibacterial activity than its acrylic counterparts. A correlation between the kinetic property and the antibacterial activity suggested that a conjugate addition may involve in the antibacterial mechanism of these unsaturated esters. Graphical abstract: [Figure not available: see fulltext.].
Efficient cu-catalyzed atom transfer radical addition reactions of fluoroalkylsulfonyl chlorides with electron-deficient alkenes induced by visible light
Tang, Xiao-Jun,Dolbier, William R.
supporting information, p. 4246 - 4249 (2015/04/14)
Fluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron-deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α-chloro-β-fluoroalkylcarbonyl products in excellent yields through an atom transfer radical addition (ATRA) process. Facile nucleophilic replacement of the α-chloro substituent is shown to lead to further diverse functionalization of the products.
Direct Photoredox-Catalyzed Reductive Difluoromethylation of Electron-Deficient Alkenes
Tang, Xiao-Jun,Zhang, Zuxiao,Dolbier, William R.
supporting information, p. 18961 - 18965 (2016/01/26)
Photoredox-catalyzed reductive difluoromethylation of electron-deficient alkenes was achieved in one step under tin-free, mild and neutral conditions. This protocol affords a facile method to introduce RCF2 (R=H, Ph, Me, and CH2N3) groups at sites β to electron-withdrawing groups. It was found that TTMS (tris(trimethylsilyl)silane) served nicely as both the H-atom donor and the electron donor in the catalytic cycle. Experimental and DFT computational results provided evidence that RCF2 (R=H, Ph, Me) radicals are nucleophilic in nature.
How much does the hybridization of a carbon atom affect the transmission of the substituent effect on the chemical shift?
Jeong, Eun Jeong,Lee, In-Sook Han
, p. 295 - 299 (2015/03/03)
1H and 13C NMR spectra of aryl esters of propionic acid, acrylic acid, and propiolic acid were systematically examined to find out the substituent effect on the chemical shift. The values of the chemical shift of the carbonyl carbon showed an inverse correlation with the Hammett ?3 values, and the magnitude of the slope was the largest with the propiolates. The ?± carbons of acrylates and propiolates also showed an inverse correlation with much smaller values of the slopes than those of the carbonyl carbons; but those of the propionates showed absolutely no correlation. However, the ?2 carbons of acrylates and propiolates showed normal correlation with larger values of the slopes. The signs and the magnitudes of the slopes may be understood by the transmission of the substituent electronic effect through bonds as well as through space. The propiolyloxy group also showed a significantly large effect on the 13C chemical shift values of the benzene ring.
Syntheses and characterisation of novel cyclodextrin vinyl derivatives from cyclodextrin-nitrophenol-derivatives
Nielsen, Anne L.,Steffensen, Kim,Wimmer, Reinhard,Worm-Leonhard, Martin,Larsen, Kim L.
experimental part, p. 303 - 315 (2011/11/29)
In this study novel reactive α-, β- and γ-cyclodextrin-esters (acrylate, pent-4-enoate and undec-10-enoate) have been synthesised and characterised. The syntheses were carried out by using nitrophenol-esters with the ability to form inclusion complexes wi
The reactions of aryl acrylates under Baylis-Hillman conditions
Perlmutter, Patrick,Puniani, Evaloni,Westman, Gunnar
, p. 1715 - 1718 (2007/10/03)
The use of aryl acrylates in the Baylis-Hillman reaction is reported. In contrast to their alkyl counterparts these acrylates react very rapidly with aldehydes, often yielding cyclic products arising from reaction of the initial adduct with a second molecule of aldehyde.
