- Organoseleno cytostatic derivatives: Autophagic cell death with AMPK and JNK activation
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Selenocyanates and diselenides are potential antitumor agents. Here we report two series of selenium derivatives related to selenocyanates and diselenides containing carboxylic, amide and imide moieties. These compounds were screened for their potency and selectivity against seven tumor cell lines and two non-malignant cell lines. Results showed that MCF-7 cells were especially sensitive to the treatment, with seven compounds presenting GI50 values below 10 μM. Notably, the carboxylic selenocyanate 8b and the cyclic imide 10a also displayed high selectivity for tumor cells. Treatment of MCF-7 cells with these compounds resulted in cell cycle arrest at S phase, increased levels of pJNK and pAMPK and caspase independent cell death. Autophagy inhibitors wortmannin and chloroquine partially prevented 8b and 10a induced cell death. Consistent with autophagy, increased Beclin1 and LC3-IIB and reduced SQSTM1/p62 levels were detected. Our results point to 8b and 10a as autophagic cell death inducers.
- Garnica, Pablo,Encío, Ignacio,Plano, Daniel,Palop, Juan A.,Sanmartín, Carmen
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- New polymer systems based on alicyclic polyimides
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Specific features of modification of some alicyclic polyimides with polyamido acids derived from aromatic tetracarboxylic acid dianhydrides were studied. The possibility of preparing new polymer systems with improved characteristics was demonstrated.
- Zhubanov,Kravtsova,Mukhamedova,Bekmagambetova
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- Synthesis, crystal structure, spectroscopic properties and potential anti-cancerous activities of four unsaturated bis-norcantharimides
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Four unsaturated norcantharimide (UNCI) dimers were synthesized and characterized by elemental analysis, ESI-QTOF-MS, FT/IR, UV-Vis, 1H and 13C NMR as well as single crystal X-ray diffraction. In addition, theoretical studies have been investigated to compare with the experimental findings. Introduction of various lengths of single bond link chains provides high conformational flexibility and thus unusual molecular and crystal structures for dimers. Two of the four dimers twist into helicate, but crystallize into centrosymmetric lattice; one adopts approximately centrosymmetric conformer, but packs into non-centrosymmetric polar space group (P21). Moreover, in vitro cytotoxic activities of four UNCI dimers and their corresponding saturated NCI dimers were evaluated. All four UNCI dimers are inactive and one NCI dimer shows modest cytotoxicity. These findings were compared with the relevant results in literature. It is found that the antitumor properties of UNCI/NCI dimers depend mainly on the length of link chains (the longer chain, the higher therapeutic efficacy) and have relationship with the double bond, which requires more experimental support.
- Cheng, Shuang-Shuang,Shi, Yan,Ma, Xiao-Na,Xing, Dian-Xiang,Liu, Lian-Dong,Liu, Yun,Zhao, Yun-Xue,Sui, Qi-Cheng,Tan, Xue-Jie
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- New Dielectric Elastomers with Variable Moduli
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Dielectric elastomers have been widely investigated for muscle-like soft actuators and capacitive sensors. Mechanical properties play a central role in the performances of the active material. Most elastomers have specific moduli pre-determined by the polymers' molecular structures, which are not suitable for applications in changing working conditions as natural muscles are capable of. Here new dielectric elastomers are described exhibiting variable moduli controlled via thermal treatment. The elastomers contain furan-maleimide Diels-Alder adduct moieties to administer the crosslinking densities of the elastomeric networks via reversible Diels-Alder/retro-Diels-Alder cycloaddition reaction, resulting in changes in the elastomers' moduli. One of the synthesized elastomers has moduli that can be controlled between 0.17 and 0.52 MPa incrementally and reversibly. Capacitive strain sensors based on this elastomer can be operated in both rigid and soft modes to achieve variable sensing response up to 30% linear strain. Actuators were fabricated and operated in both high strain mode (35% actuation area strain at 65 MV m-1) and high force output mode (0.55 MPa at 104 MV m-1). The elastomers can exhibit a range of stress-strain outputs in similar fashion as muscle.
- Hu, Wei,Ren, Zhi,Li, Junpeng,Askounis, Erin,Xie, Zhixin,Pei, Qibing
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- ACCELERATION OF A DIELS-ALDER REACTION IN AN ULTRACENTRIFUGE
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The reaction rate for the Diels-Alder reaction between maleic anhydride and furan is increased when performed in an ultracentrifuge.
- Dolata, Daniel P.,Bergman, Rolf
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- Synthesis and reactivity of a fluorinated N-alkylmaleimide towards free-radical grafting and polymerization reactions
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A new fluorinated N-alkylmaleimide, N-(2-pentadecafluoro-n-octanoyloxy)- ethyl)maleimide (FOMI), was synthesized from perfluorooctyl carboxylic acid (FOCA) by reaction of the furan adduct of maleic anhydride (MAH) with ethanolamine and esterification of the resulting alcohol-imide. The reactivity of FOMI in free-radical reactions such as copolymerization with butyl vinyl ether (BVE) and grafting onto olefin copolymers (OCP) was investigated. Copolymerization with 2/1 molar excess BVE yields a copolymer with 63 mol% FOMI in moderate conversion, indicating that homopropagation of the maleimide prevails over comonomer alternation. The thermal stability of FOMI is quite poor, with onset of the pyrolytic loss of the N-perfluoroalkylcarboxyethyl moiety just above 100 °C, similarly to that of FOCA. This restricts the possibilities for direct melt functionalization of OCP with FOMI. To bypass this limitation three distinct approaches were preliminarly investigated. These were respectively based on either direct grafting of FOMI at low temperature, or reaction of a MAH-grafted polyolefin with a low molecular weight amine or amino-terminated oligomer bearing the perfluoroheptyl group. A functionalization degree FD=2% was achieved by solution grafting of a linear very low density polyethylene (VLDPE) with FOMI and Perkadox 16 as the free-radical initiator. The relatively high grafting efficiency was attributed to the growth of some oligomeric FOMI grafts onto the OCP. The alternative routes of post-modification of VLDPE- g -MAH by imidization with an amidoamine obtained by amidation of FOCA with a diamine or an amino-terminated FOMI/BVE oligomer, respectively, were also preliminarly investigated.
- Castelvetro, Valter,Aglietto, Mauro,Ciardelli, Francesco,Spagnoli, Federica
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- Albumin-micelles via a one-pot technology platform for the delivery of drugs
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A new micelle delivery platform based on albumin coated nanoparticles is able to selectively deliver the payload to cancerous cells while healthy cells remain less affected. The technology is simple and can be used in a one-pot procedure. the Partner Organisations 2014.
- Jiang, Yanyan,Liang, Mingtao,Svejkar, Domenic,Hart-Smith, Gene,Lu, Hongxu,Scarano, Wei,Stenzel, Martina H.
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- Reversible-Addition Fragmentation Chain Transfer Step-Growth Polymerization
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Reversible-addition fragmentation chain transfer (RAFT) polymerization has been widely explored since its discovery due to its structural precision, versatility, and efficiency. However, the lack of tunability of the polymer backbone limits some applications. Herein, we synergistically combine RAFT and step-growth polymerization mechanisms, by employing a highly selective insertion process of a single monomer with a RAFT agent, to achieve RAFT step-growth polymerization. A unique feature of the RAFT step-growth polymers is that each backbone repeat unit bears a pendant RAFT agent, which can subsequently graft side chains in a second polymerization step and afford molecular brush polymers. Enabled by cleavable backbone functionality, we demonstrate transformation of the resulting brushlike polymers into linear chains of uniform size upon a stimulus.
- Archer, Noel Edward,Grant, Michael Jeffery,Tanaka, Joji,You, Wei
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supporting information
p. 15918 - 15923
(2021/10/21)
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- Bridging from the Sequence to Architecture: Graft Copolymers Engineering via Successive Latent Monomer and Grafting-from Strategies?
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The on-demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between polymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and distributions were achieved using successive latent monomer and grafting-from strategies. The hydroxyl group functionalized furan/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of L-lactide or ε-caprolactone, resulting in a library of multicomponent copolymers via grafting-from strategy. The initiating efficiency reached to ~100% with variable molecular weight (21300—58600 Da) and narrow distributions (DM 1.25), indicating that such graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal properties of the well-defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new method in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.
- Zhang, Yajie,Cao, Xiaohuan,Gao, Yang,Xie, Yujie,Huang, Zhihao,Zhang, Zhengbiao,Zhu, Xiulin
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supporting information
p. 1273 - 1280
(2021/05/04)
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- A Mechanochemical Reaction Cascade for Controlling Load-Strengthening of a Mechanochromic Polymer
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We demonstrate an intermolecular reaction cascade to control the force which triggers crosslinking of a mechanochromic polymer of spirothiopyran (STP). Mechanochromism arises from rapid reversible force-sensitive isomerization of STP to a merocyanine, which reacts rapidly with activated C=C bonds. The concentration of such bonds, and hence the crosslinking rate, is controlled by force-dependent dissociation of a Diels–Alder adduct of anthracene and maleimide. Because the adduct requires ca. 1 nN higher force to dissociate at the same rate as that of STP isomerization, the cascade limits crosslinking to overstressed regions of the material, which are at the highest rate of material damage. Using comb polymers decreased the minimum concentration of mechanophores required to crosslinking by about 100-fold compared to previous examples of load-strengthening materials. The approach described has potential for controlling a broad range of reaction sequences triggered by mechanical load.
- Boulatov, Roman,Pan, Yifei,Tian, Yancong,Wang, Chenxu,Weng, Wengui,Xiang, Shishuai,Xu, Piaoxue,Zhang, Huan
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supporting information
p. 21980 - 21985
(2020/10/02)
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- Method for preparing 4, 10-dioxabicyclo[5.2. 1.0(2, 6)]decane-8-ene-3-ketone
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The invention discloses a method for preparing 4, 10-dioxabicyclo[5.2. 1.0(2, 6)]decane-8-ene-3-ketone, and belongs to the technical field of organic chemistry. Maleic anhydride is used as a raw material, and is sequentially subjected to a selective reduction reaction and a Diels-Alder reaction to obtain the 4, 10-dioxabicyclo[5.2. 1.0(2, 6)]decane-8-ene-3-ketone. According to the method, the rawmaterials are easy to obtain, the reaction conditions of each step are simple, the side reaction of polymerization of double bonds in the product can be effectively inhibited, verification is carriedout in kilogram-scale reaction or above, and the process batch reproducibility is good.
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Paragraph 0023-0025
(2020/05/30)
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- Chemoselective 18F-incorporation into pyridyl acyltrifluoroborates for rapid radiolabelling of peptides and proteins at room temperature
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A new prosthetic group is reported for 18F-labelling of peptides and proteins based on the chemoselective ligation of potassium acyltrifluoroborates (KATs) and hydroxylamines without any detectable 18F/19F isotope exchange at the acyltrifluoroborate moiety. The new building block is appended via a common amide bond at room temperature with no need for protecting groups which enables an effective orthogonal 18F-radiolabelling.
- Chiotellis, Aristeidis,Ahmed, Hazem,Betzel, Thomas,Tanriver, Matthias,White, Christopher J.,Song, Haewon,Da Ros, Sara,Schibli, Roger,Bode, Jeffrey W.,Ametamey, Simon M.
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supporting information
p. 723 - 726
(2020/01/29)
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- Method for synthesizing phthalic anhydride by catalyzing furan and maleic anhydride
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The invention belongs to the technical field of bio-based chemicals, and particularly relates to a method for synthesizing phthalic anhydride by catalyzing furan and maleic anhydride. According to thepreparation method for catalyzing furan and maleic anhydride to generate phthalic anhydride, furan and maleic anhydride are used as raw materials, a Diels-Alder reaction and a dehydration step are adopted for producing phthalic anhydride, wherein the furan and maleic anhydride are obtained from furfural converted from biomass. The method provided by the invention is green, economical and renewable, reduces the use of non-renewable traditional resources, provides advanced technical support for industrial production of bio-based phthalic anhydride, and has broad application prospects.
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Paragraph 0026-0033; 0053-0055; 0061-0064; 0069-0072; 0077
(2020/11/23)
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- Norcantharidin carboxylic acid monofluorobenzyl ester and synthesis method and anti-tumor application thereof
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The invention provides synthesis and anti-tumor application of norcantharidin carboxylic acid monofluorobenzyl ester with a structural formula shown as I in the specification. The specific structure of the norcantharidin carboxylic acid monofluorobenzyl ester as shown in the formula I is shown in the specification, and activity tests show that the norcantharidin carboxylic acid monofluorobenzyl ester as shown in the formula I, which is designed and synthesized by the invention, is a suitable anti-tumor candidate drug, especially as an anti-liver cancer candidate drug. Compared with a positivecontrol drug norcantharidin, the norcantharidin sodium salt has the advantage that the water solubility, the stability and the anti-tumor activity are improved. In addition, the synthesis method of norcantharidin carboxylic acid monofluorobenzyl ester has the advantages that the raw materials are easy to obtain, and the operation and the implementation are very easy.
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Paragraph 0028; 0033-0034
(2020/07/02)
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- Homocam ptothecin 5-ene norcantharidin acid ester derivative, and regioselective synthesis method thereof
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The invention discloses a homocam ptothecin 5-ene norcantharidin acid ester derivative represented by fomula I, and a regioselective synthesis method thereof, wherein R is selected from C1-C6 alkyl, substituted alkyl, and cycloalkyl. It is confirmed by activity test that the homocam ptothecin 5-ene norcantharidin acid ester derivative I possesses excellent anti-tumor effect, and is especially highin inhibition activity on liver cancer, stomach cancer, colorectal carcinoma and pancreas cancer. According to the preparation method of the homocam ptothecin 5-ene norcantharidin acid ester derivative, the raw materials are easily available; cost is low; synthesis reaction regioselectivity is extremely high; target product yield is high; and preparation is convenient.
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Paragraph 0025-0029
(2019/11/21)
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- Homocamptothecin norcantharidinate derivative, and regioselective synthesis method thereof
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The invention provides a homocamptothecin norcantharidinate derivative I and a regioselective synthesis method thereof in the fields of design and synthesis of novel drugs. The homocamptothecin norcantharidinate derivative I has a structural formula as shown in a formula I which is described in the specification. In the formula I, R is selected from the group consisting of C1-C6 alkyl, substitutedalkyl and cycloalkyl groups. Activity test results prove that the homocamptothecin norcantharidinate derivative I designed and synthesized by using the method provided by the invention has good antitumor effect, and specifically has high activity on liver cancer, gastric cancer, colon cancer and pancreatic cancer. In addition, the method for preparing the homocamptothecin norcantharidinate derivative I provided by the invention has the advantages of easily-available raw materials, low cost, extremely-high synthesis reaction regioselectivity and high target product yield; and the homocamptothecin norcantharidinate derivative I provided by the invention is easy to be prepared.
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Paragraph 0025; 0028-0029
(2019/11/21)
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- Glass-transition temperature governs the thermal decrosslinking behavior of Diels–Alder crosslinked polymethacrylate networks
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A series of Diels–Alder (DA) crosslinked polymethacrylate networks covering a broad range of glass-transition temperatures (Tg) was prepared to establish the relationship between the Tg and the thermal decrosslinking behavior of these networks. A series of permanently crosslinked and uncrosslinked analogues were also prepared to better understand the thermoset-to-thermoplastic transition occurring in the DA networks at elevated temperatures. The network series were studied using dynamic mechanical analysis, which established an inverse relationship between Tg and decrosslinking ability. Differential scanning calorimetry confirmed the viability of the DA linkages in all formulations, and a trapping experiment with 9-anthracenemethanol demonstrated that even the least responsive network was capable of undergoing decrosslinking given appropriate thermal treatment. While polymer chain mobility has long been understood to be a critical factor in healable materials, this work verifies the importance of this parameter in the decrosslinking of DA networks.
- Dobbins, Daniel J.,Scheutz, Georg M.,Sun, Hao,Crouse, Christopher A.,Sumerlin, Brent S.
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- A strategy combining quantitative reactions and reversible-covalent chemistry for sequential synthesis of sequence-controlled polymers with different sequences
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A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition.
- Xu, Chao-Ran,Zhang, Ze,Pan, Cai-Yuan,Hong, Chun-Yan
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p. 294 - 304
(2019/04/25)
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- Camptothecin-glycine-norcantharidin conjugate and application thereof
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The invention provides a camptothecin-glycine-norcantharidin conjugate I and a preparation method thereof. R in the formula I is selected from C1-C6 alkyl groups, substituted alkyl groups, cycloalkylgroups, benzyl groups or substituted benzyl groups. Activity tests prove that the designed and synthesized camptothecin-glycine-norcantharidin conjugate I has an excellent antitumor effect, and especially has high activity on liver cancer, stomach cancer, colon cancer and pancreatic cancer. Additionally, the preparation method of the camptothecin-glycine-norcantharidin conjugate I has the advantages of easily available raw materials, low cost, high yield of the target product, and easiness in preparation.
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Paragraph 0020-0025
(2019/12/29)
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- Camptothecin-glycine-5,6-didehydronorcantharidin conjugate and application thereof
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The invention provides a camptothecin-glycine-5,6-didehydronorcantharidin conjugate I and a preparation method thereof. R in the formula I is selected from C1-C6 alkyl groups, substituted alkyl groups, cycloalkyl groups, benzyl groups or substituted benzyl groups. Activity tests prove that the designed and synthesized camptothecin-glycine-5,6-didehydronorcantharidin conjugate I has an excellent antitumor effect, and especially has high activity on liver cancer, stomach cancer, colon cancer and pancreatic cancer. Additionally, the preparation method of the camptothecin-glycine-5,6-didehydronorcantharidin conjugate I has the advantages of easily available raw materials, low cost, high yield of the target product, and easiness in preparation.
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Paragraph 0019; 0021-0023
(2019/12/29)
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- Camptothecin-glycine-5,6-dibromonorcantharidin conjugate and application thereof
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The invention provides a camptothecin-glycine-5,6-dibromonorcantharidin conjugate I and a preparation method thereof. R in the formula I is selected from C1-C6 alkyl groups, substituted alkyl groups,cycloalkyl groups, benzyl groups or substituted benzyl groups. Activity tests prove that the designed and synthesized camptothecin-glycine-5,6-dibromonorcantharidin conjugate I has an excellent antitumor effect, and especially has high activity on liver cancer, stomach cancer, colon cancer and pancreatic cancer. Additionally, the preparation method of the camptothecin-glycine-5,6-dibromonorcantharidin conjugate I has the advantages of easily available raw materials, low cost, high yield of the target product, and easiness in preparation.
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Paragraph 0019; 0021-0023
(2019/12/29)
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- CONTINUOUS PROCESS FOR CYCLOADDITION REACTIONS
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The invention is directed to a process for the continuous preparation of a cycloadduct product from the reaction of a furanic with a dienophile, comprising heating a first liquid feed stream comprising the dienophile and a solvent in which the dienophile is dissolved; providing a second liquid feed stream comprising the furanic; leading the first liquid feed stream and the second liquid feed stream into a continuous reactor to produce a product solution stream comprising the cycloadduct product; and leading the product solution stream to an product isolation zone to produce an isolated cycloadduct product. A further aspect of the invention is an apparatus for carrying out this reaction.
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Page/Page column 12; 13
(2019/04/27)
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- Stereochemical effects on the mechanochemical scission of furan-maleimide Diels-Alder adducts
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Clarifying the correlation between the chemical structure of mechanophores and their mechanical reactivity informs the design of mechanochemical systems. One specific correlation that has received much recent attention is that between stereoisomerism and mechanical reactivity. Here, we report previously unobserved differences in the mechanical reactivity of furan-maleimide Diels-Alder (DA) stereoisomers. We evaluated the internal competition between the mechanically triggered retro-DA reaction and the mechanochemical ring opening of gem-dichlorocyclopropane mechanophores in the pulsed sonication of polymer solutions. The relative extent of the two sonomechanochemical reactions in the same polymer shows that the endo DA isomer exhibits greater mechanical lability than its exo isomer. This result contrasts with recent measurements of the relative rates of scission in a similar system and points to potential enhanced sensitivity obtained through the use of internal competition as opposed to absolute rates in assessing mechanical reactivity in sonication studies.
- Wang, Zi,Craig, Stephen L.
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supporting information
p. 12263 - 12266
(2019/10/22)
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- Aromatic Nitrogen Mustard-Based Autofluorescent Amphiphilic Brush Copolymer as pH-Responsive Drug Delivery Vehicle
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Delivery of clinically approved nonfluorescent drugs is facing challenges because it is difficult to monitor the intracellular drug delivery without incorporating any integrated fluorescence moiety into the drug carrier. The present investigation reports the synthesis of a pH-responsive autofluorescent polymeric nanoscaffold for the administration of nonfluorescent aromatic nitrogen mustard chlorambucil (CBL) drug into the cancer cells. Copolymerization of poly(ethylene glycol) (PEG) appended styrene and CBL conjugated N-substituted maleimide monomers enables the formation of well-defined luminescent alternating copolymer. These amphiphilic brush copolymers self-organized in aqueous medium into 25-68 nm nanoparticles, where the CBL drug is enclosed into the core of the self-assembled nanoparticles. In vitro studies revealed ~70% drug was retained under physiological conditions at pH 7.4 and 37 °C. At endolysosomal pH 5.0, 90% of the CBL was released by the pH-induced cleavage of the aliphatic ester linkages connecting CBL to the maleimide unit. Although the nascent nanoparticle (without drug conjugation) is nontoxic, the drug conjugated nanoparticle showed higher toxicity and superior cell killing capability in cervical cancer (HeLa) cells rather than in normal cells. Interestingly, the copolymer without any conventional chromophore exhibited photoluminescence under UV light irradiation due to the presence of "through-space" π- π interaction between the C=O group of maleimide unit and the adjacent benzene ring of the styrenic monomer. This property helped us intracellular tracking of CBL conjugated autofluorescent nanocarriers through fluorescence microscope imaging. Finally, the 4-(4-nitrobenzyl)pyridine (NBP) colorimetric assay was executed to examine the ability of CBL-based polymeric nanomaterials toward alkylation of DNA.
- Saha, Biswajit,Choudhury, Neha,Seal, Soma,Ruidas, Bhuban,De, Priyadarsi
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p. 546 - 557
(2019/01/08)
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- A Combined Photochemical and Multicomponent Reaction Approach to Precision Oligomers
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We introduce the convergent synthesis of linear monodisperse sequence-defined oligomers through a unique approach, combining the Passerini three-component reaction (P-3CR) and a Diels–Alder (DA) reaction based on photocaged dienes. A set of oligomers is prepared resting on a Passerini linker unit carrying an isocyano group for chain extension by P-3CR and a maleimide moiety for photoenol conjugation enabling a modular approach for chain growth. Monodisperse oligomers are accessible in a stepwise fashion by switching between both reaction types. Employing sebacic acid as a core unit allows the synthesis of a library of symmetric sequence-defined oligomers. The oligomers consist of alternating P-3CR and photoblocks with molecular weights up to 3532.16 g mol?1, demonstrating the successful switching from P-3CR to photoenol conjugation. In-depth characterization was carried out including size-exclusion chromatography (SEC), high-resolution electrospray ionization mass spectrometry (ESI-MS) and NMR spectroscopy, evidencing the monodisperse nature of the precision oligomers.
- Konrad, Waldemar,Bloesser, Fabian R.,Wetzel, Katharina S.,Boukis, Andreas C.,Meier, Michael A. R.,Barner-Kowollik, Christopher
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supporting information
p. 3413 - 3419
(2018/02/09)
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- Maleimide end-functionalized poly(2-oxazoline)s by the functional initiator route: Synthesis and (bio)conjugation
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The synthesis of poly(2-ethyl-2-oxazoline)s with a maleimide group at the α chain end was carried out from new sulfonate ester initiators bearing a furan-protected maleimide group. The conditions of the polymerization were optimized for 50 °C using conventional heating (in contrast to microwave irradiation) to counteract the thermal lability of the cycloadduct introduced to protect the maleimide double bond. At this temperature, a tosylate variant was found to be unable to initiate the polymerization after several days. The controlled polymerization of 2-ethyl-2-oxazoline with a nosylate derivative was, however, successful as shown by kinetic experiments monitored by gas chromatography (GC) and size-exclusion chromatography (SEC). Poly(2-ethyl-oxazoline)s of various molar masses (4500 n -1) with narrow dispersity (1H NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Finally, the conjugation of maleimide-functionalized poly(2-oxazoline) to a model protein (bovine serum albumin) was demonstrated by gel electrophoresis and MALDI-ToF mass spectrometry.
- Gil Alvaradejo, Gabriela,Glassner, Mathias,Hoogenboom, Richard,Delaittre, Guillaume
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p. 9471 - 9479
(2018/03/21)
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- Precisely albumin-hitchhiking tumor cell-activated reduction/oxidation-responsive docetaxel prodrugs for the hyperselective treatment of breast cancer
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The anticancer efficacy of chemotherapy is greatly limited by short blood circulation and poor tumor selectivity. Thus, anticancer prodrugs with prolonged systemic circulation, tumor-specific distribution and bioactivation, could significantly strengthen the chemotherapy efficacy. Herein, we design two novel tumor cell reduction/oxidation-responsive docetaxel (DTX) prodrugs, DTX-maleimide conjugates with disulfide bond (DSSM) or thioether bond (DSM) linkages, to evaluate the roles of different sensitive linkages in drug release, pharmacokinetics and therapeutic efficacy. An ester bond-linkage prodrug (DM) is utilized as a non-sensitive control. DSSM and DSM show reduction- or oxidation-sensitive release behavior, respectively, and exhibit hyperselective bioactivation and cytotoxicities between cancerous and normal cells. They could instantly hitchhike blood circulating albumin after i.v. administration with albumin-binding half-lives as short as 1 min, resulting in prolonged systemic circulation, increased tumor accumulation. In response to the upregulated reduction/oxidation environment within tumor cells, DSSM and DSM exhibit selectively release capacity in tumor tissues, their TAITumor/Liver values are over 30-fold greater than DM. Combining the above delivery advantages into one, DSSM and DSM achieve enhanced antitumor efficacy of DTX. Such a uniquely developed strategy, integrating high albumin-binding capability and reduction/oxidation-sensitive drug superselective release in tumors, has great potential to be applied in clinical cancer therapy.
- Wei, Wei,Luo, Cong,Yang, Jincheng,Sun, Bingjun,Zhao, Dongyang,Liu, Yan,Wang, Yingli,Yang, Wenqian,Kan, Qiming,Sun, Jin,He, Zhonggui
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p. 187 - 199
(2018/07/25)
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- Synthesis and structure-activity relationship study of novel 3-heteroarylcoumarins based on pyridazine scaffold as selective MAO-B inhibitors
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Compounds of hybrid structure pyridazine-coumarin were discovered as potent, selective and reversible inhibitors of monoamine oxidase B (MAO-B). These compounds were synthesized in good yield following a multistep approach based on Knoevenagel reaction and using as key intermediate pyridazinone 16, which was obtained from maleic anhydride and furan. Compounds 9b and 9d are the most active compounds of these series, with IC50 values in the sub-micromolar range, and lack of cytotoxic effects. Theoretical calculation of ADME properties also suggested a good pharmacokinetic profile for both compounds. Docking simulations provided insights into enzyme inhibitor interactions and allowed us to rationalize the observed structure-activity relationships (SARs).
- Costas-Lago, María Carmen,Besada, Pedro,Rodríguez-Enríquez, Fernanda,Vi?a, Dolores,Vilar, Santiago,Uriarte, Eugenio,Borges, Fernanda,Terán, Carmen
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supporting information
p. 1 - 11
(2017/08/10)
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- Diacetylene-Based C 2h-Symmetric Monomers for Two-Dimensional-Polymer Synthesis
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Two linear monomers with two terminal photoreactive groups (anthracene or maleimide) embedded in a diacetylene skeleton were synthesized for two-dimensional-polymer synthesis. Both of them were crystallized and their single-crystal structures were solved. It was found that the size of terminal groups can be critical for diacetylene's arrangement. The crystal structure of dimaleimide monomer revealed that maleimide groups strongly stacking in antiparallel and the photo-induced [2+2] cycloaddition of stacked maleimides was preliminary studied.
- Song, Mengyao,Ma, Hanbing,Ren, Minghan,Ai, Zhaoquan,Li, Ming
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supporting information
p. 445 - 450
(2017/02/24)
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- Study on the curing reaction kinetics of a novel epoxy system
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The anhydride curing agent of 3,6-enodro-1,2,3,6-tetrahydrophthalic anhydride (OBPA) and the reactive epoxy diluent of furfuryl glycidyl ether (FGE) were prepared and characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The curing reaction kinetics process of an EP/OBPA/FGE epoxy system was studied by non-isothermal DSC methods. The parameters of the kinetics were calculated using the Kissinger model, Crnae model, Ozawa model and β-T (temperature-heating speed) extrapolation, respectively. In addition, the effect of FGE on the thermomechanical properties (glass transition temperature) and mechanical properties (flexural strength and the tensile strength) in the EP/OBPA/FGE were studied, indicating that when the content of FGE was 10 wt% the epoxy system reaches the best mechanical properties.
- Ding, Jiheng,Peng, Wanjun,Luo, Ting,Yu, Haibin
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p. 6981 - 6987
(2017/02/05)
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- METHOD FOR PREPARING 2,5-DISUBSTITUTED FURAN COMPOUND
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Disclosed is a method for preparing a 2,5-disubstituted furan compound. The 2,5-disubstituted furan compound is prepared in a simple, convenient and highly efficient way by reacting 2,3-dicarboxylic anhydride-7-oxabicyclo[2.2.1]hept-5-ene and/or furan with an acylating reagent and/or an alkylating reagent. The preparation method is simple and efficient, has a short process and less by-products, and the 2,5-disubstituted furan compound prepared by using the method has a high purity, and can satisfy the requirements for being used as a raw material for engineering plastics, such as high-performance polyesters, epoxy resins, polyamides, polyurethanes and the like, and as a chemical raw material and a pharmaceutical intermediate raw material.
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Page/Page column 4-9
(2017/11/30)
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- Bromo norcantharidin monoacid methyl ester and its synthetic method and application
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The invention discloses bromo-norcantharidin mono-methyl ester with a structural formula as shown in a formula I in the specification. The bromo-norcantharidin mono-methyl ester is ring-opened 5,6-dibromo-norcantharidin mono-methyl ester. Activity tests prove that the bromo-norcantharidin mono-methyl ester has a good liver cancer resistance, and can be used as an efficient low-toxicity cantharidin anti-tumor medicine. The synthesis process has good selectivity, easily available raw materials, low cost and simple synthesizing route, and is convenient to operate and implement; and the synthesized product has small toxicity, high yield and high purity. Therefore, the process has the characteristics of high efficiency, convenience and low cost.
- -
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Paragraph 0028-0030
(2017/08/25)
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- Chlorin derivatives sterically-prevented from self-aggregation with high antitumor activity for photodynamic therapy
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In this study two new chlorin derivatives sterically prevented from aggregation were synthesised by the Diels-Alder reaction between protoporphyrin IX dimethyl ester and 1-(2-hydroxyethyl)maleimide. The compounds were fully characterised by 1H NMR, 13C NMR, UV-Vis and high-resolution mass spectroscopy (HRMS) and their photochemical properties such as singlet oxygen quantum yield (?0), fluorescence quantum yield (?f) and photodegradation were also evaluated. Furthermore, the partition coefficient (log P) revealed that these compounds present amphiphilic properties. Studies of the photodynamic action in tumour cells (HEp-2 and HeLa) and non-tumour cells (Vero) were also performed in order to confirm the photodynamic therapy (PDT) activity that was indicated by the preliminary photophysical studies. Those phototoxicity results were 55–77% higher than the results obtained with the commercial photosensitiser verteporfin. Finally, cytotoxic assays were performed with the new photosensitiser candidates and cell death was determined using fluorescence microscopy, which provided information about the mechanisms of cell death. In general, we have obtained improved and accessible compounds for PDT studies, as highlighted by the research presented here.
- Linares, Irwin A.P.,de Oliveira, Kleber T.,Perussi, Janice Rodrigues
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p. 518 - 527
(2017/06/29)
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- Method of manufacturing a polymerizable monomer
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PROBLEM TO BE SOLVED: To provide a method of producing a lactone compound (polymerizable monomer) which has few impurities and high yields, and serves as materials for medicaments, agricultural chemicals, functional resins or the like.SOLUTION: A method of producing a polymerizable monomer represented by the formula by making an alcohol compound react with a (meth) acrylate esterification agent in the presence of a catalyst, wherein the catalyst is a metal oxide and the (meth) acrylate esterification agent is a (meth) acrylate anhydride.
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Paragraph 0019; 0020
(2017/09/26)
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- METHODS FOR PRODUCTION OF TEREPHTHALIC ACID FROM ETHYLENE OXIDE
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The present invention provides methods for the production of terephthalic acid and derivatives thereof using ethylene oxide, carbon monoxide and furan as feedstocks. The process is characterized by high yields and high carbon efficiency. The process can utilize 100% biobased feedstocks (EO via ethanol, CO via biomass gasification, and furan via known processes from cellulosic feedstocks).
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Page/Page column 26-28
(2017/01/23)
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- Albumin-polymer conjugate nanoparticles and their interactions with prostate cancer cells in 2D and 3D culture: Comparison between PMMA and PCL
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Using proteins as the hydrophilic moiety can dramatically improve the biodegradability and biocompatibility of self-assembled amphiphilic nanoparticles in the field of nanomedicine. In this study, we fabricated and evaluated curcumin loaded albumin-polycaprolactone nanoparticles as a novel drug delivery system for prostate carcinoma therapeutics and compared their performance to poly(methyl methacrylate) (PMMA), a non-degradable and amorphous polymer. The maleimide functionalized poly(ε-caprolactone) (PCL) was obtain using ring opening polymerization (ROP) of ε-caprolactone where N-(2-hydroxyethyl)maleimide was used as an initiator. The resorbable albumin-polymer conjugate was prepared by conjugating the hydrophobic maleimide-terminated PCL to the hydrophilic bovine serum albumin (BSA) via a simple Michael addition reaction. PMMA was conjugated in a similar manner. The amphiphilic BSA-polymer conjugates can self-assemble into nanoparticles, displaying well-defined structure, prolonged storage stability, and excellent biocompatibility. The BSA nanoparticles, with encapsulated curcumin, exhibited highly enhanced antitumor activity compared to free curcumin. Furthermore, the high efficacy of the curcumin loaded nanoparticles was verified by effectively inhibiting the growth of three-dimensional LNCaP multicellular tumour spheroids. The cytotoxicity was attributed to the efficient cellular uptake of the nanoparticles through caveolic endocytosis. The direct comparison between PCL and the PMMA revealed that drug loading and release as well as cytotoxicity is not significantly affected by the nature of the polymer. However, it seems that nanoparticles based on PMMA penetrate quicker into LNCaP multicellular tumour spheroids thanks to the increased stability. The faster penetration was found to reduce the toxicity of the nanoparticles as evidenced by the lower number of dead cells. In contrast, the fully degradable PCL-based nanoparticles were more efficient in delivering the drug, thus limiting the growth of LNCaP multicellular tumour spheroids.
- Jiang, Yanyan,Lu, Hongxu,Dag, Aydan,Hart-Smith, Gene,Stenzel, Martina H.
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p. 2017 - 2027
(2016/03/22)
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- Norcantharidin monomer-acid monoester derivative and anti-tumor application thereof
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The invention provides a norcantharidin monomer-acid monoester derivative and an application thereof. The structural formula of the derivative is shown as the No.3 formula (please see the specification), wherein R is selected from alkyl or benzyl of C1 to C3. An activity test proves that the third designed and synthesized norcantharidin monomer-acid monoester derivative has good inhabitation activity in liver cancer tumor cells, stomach cancer tumor cells and colon cancer tumor cells, and can be expected to be applied to preparing medicine for resisting the three tumors.
- -
-
Paragraph 0027; 0029; 0030
(2017/07/19)
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- Star polymer synthesis: Via λ-orthogonal photochemistry
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We introduce a light induced sequence enabling λ-orthogonal star polymer formation via an arms-first approach, based on an α,ω-functional polymer carrying tetrazole and o-methyl benzaldehyde moieties, which upon irradiation can readily undergo cycloaddition with a trifunctional maleimide core. Depending on the wavelength, the telechelic strand can be attached to the core at either photo-reactive end.
- Hiltebrandt, Kai,Kaupp, Michael,Molle, Edgar,Menzel, Jan P.,Blinco, James P.,Barner-Kowollik, Christopher
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supporting information
p. 9426 - 9429
(2016/07/29)
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- Acid-sensitive camptothecin-20-position ester derivative and antineoplastic application thereof
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The invention provides a camptothecin-20-position ester derivative having a structural formula shown as the figure 4, a preparation method of the derivative, and an antineoplastic application of the derivative. It is proved through an activity test that the camptothecin-20-position ester derivative designed and synthesized in the invention and shown as the figure 4 is a suitable antineoplastic medical candidate, especially an anti-liver-cancer, anti-stomach-cancer, and anti-colorectal-cancer medical candidate. Compared with camptothecin and cantharidin which are taken as positive-control medicines, the derivative has improved water solubility and stability, is relatively sensitive to acid, and is easy to hydrolyze. Besides, according to a synthetic method of the camptothecin norcantharidin ester derivative, raw materials are easy to get; the synthetic route is high in yield; and the method is very easy to operate and implement.
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-
Paragraph 0026; 0027; 0032; 0033
(2016/10/27)
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- Sodium demethylcantharide derivatives and antitumor application thereof
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The invention provides sodium demethylcantharide derivatives of which the structural formula is disclosed as Formula 7. The activity test proves that the designed and synthesized sodium demethylcantharide derivatives 7 have favorable inhibiting activities for liver cancer, stomach cancer and colon cancer, and thus, are hopeful to be used for preparing antitumor drugs for liver cancer, stomach cancer and colon cancer.
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Paragraph 0019; 0022; 0023
(2016/11/14)
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- Unsaturated norcantharidin methyl barium salt and antineoplastic application thereof
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The invention provides an unsaturated norcantharidin methyl barium salt derivative I and application thereof. The structural formula of the unsaturated norcantharidin methyl barium salt derivative I is shown as the formula I (see the formula I in the description). Activity tests prove that the designed and synthesized unsaturated norcantharidin methyl barium salt derivative I has good inhibitory activity for liver cancer tumor cells at low concentration, and is expected to be applied to preparation of anti-hepatoma drugs.
- -
-
Paragraph 0022; 0023
(2017/04/26)
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- Norcantharidin monoester salt derivative and its anti-tumor application (by machine translation)
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This invention has offered a kind of Norcantharidin monoester salt derivative, its structural formula such as formula 4 shown, Wherein R is selected from C1-C3 alkyl or benzyl; M is selected from positive univalent or divalent cation. Active test proves that, this invention is designed and synthesizing Norcantharidin monoester salt derivative 4 for liver cancer, stomach cancer, colon cancer, and four kinds of tumor colon cancer has good inhibition activity, is expected to be applied to the preparation of the above-mentioned four kinds of anti-tumor drug. (by machine translation)
- -
-
Paragraph 0035; 0037; 0038
(2017/04/29)
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- Camptothecin derivatives and its anti-tumor application
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The invention provides a novel camptothecin derivative expressed by a structural formula 3 as shown in the specification, and a preparation method and the antitumor application of the novel camptothecin derivative. Activity tests prove that the designed and synthesized camptothecin derivative 3 has an excellent anti-hepatoma effect and is expected to be applied clinically as a cantharidin anti-tumor medicine. Besides, the synthesis method of the camptothecin derivative 3 is easily available in raw materials, low in cost, simple in synthesis routine, high in yield and easy to operate and implement.
- -
-
Paragraph 0025; 0030; 0031; 0032; 0033
(2017/08/23)
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- Maleimide-bearing nanogels as novel mucoadhesive materials for drug delivery
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Novel maleimide-functionalised nanogels have been synthesised via the polymerisation of 2,5-dimethylfuran-protected 3-maleimidoethyl butylacrylate in the presence of presynthesised poly(N-vinylpyrrolidone) (PVP) nanogel scaffolds using surfactant-free emulsion polymerisation techniques. The protected maleimide nanogels were subsequently deprotected to generate the reactive maleimide group via a retro-Diels-Alder reaction. These activated nanogels were found to exhibit excellent mucoadhesive properties on ex vivo conjunctival tissue when compared to the known mucoadhesive chitosan. In order to determine the viability of the materials as drug carriers, nanogels were loaded with a model drug compound and the in vitro release kinetics were analysed. The nanogels could sustain the release of a model drug compound over several hours owing to the swellable hydrophilic nanogel structure, exhibiting first order release kinetics. As a consequence, these findings support the potential of these maleimide-bearing nanogels as a novel platform for sustained drug delivery.
- Tonglairoum, Prasopchai,Brannigan, Ruairí P.,Opanasopit, Praneet,Khutoryanskiy, Vitaliy V.
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p. 6581 - 6587
(2016/10/25)
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- Polymeric nanoparticles for ultrasound imaging and therapy
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Provided herein are nanobubbles designed for use in ultrasound-mediated ablation of cancer cells. The nanobubbles undergo ultrasound-mediated cavitation at an ablation threshold which is significantly decreased, relative to standard ultrasound-mediated treatment of cancer cells. In exemplary embodiments, the nanobubbles comprise an amphiphilic ABC triblock copolymer, wherein block A comprises a hydrophilic polymer, block B comprises a crosslinking polymer, and block C comprises a hydrophobic copolymer comprising (i) methyl methacrylate (MMA) and (ii) a fluorinated monomer, wherein the fluorinated monomer is present in the hydrophobic copolymer of block C at 25 mole percent or less. Related treatment and diagnostic methods, as well as materials relating to the nanobubbles are provided herein. Methods of making a random copolymer are furthermore provided herein.
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-
Page/Page column 41
(2016/09/12)
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- IMPROVED PROCESS FOR THE PREPARATION OF A BENZENE COMPOUND
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A benzene compound is prepared in a process, which comprises (i) reacting a furan compound of formula (I): wherein R1 and R2 are the same or different and independently selected from the group consisting of hydrogen, alkyl, aralkyl, -CHO, -CH2OR3, -CH(OR4 )(OR5), -COOR6, wherein R3, R4 and R5 are the same or different and are independently selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, alkylcarbonyl and arylcarbonyl, or wherein R4 and R5 together form an alkylene group, and wherein R6 is selected from the group consisting of hydrogen, alkyl and aryl, with an olefin of the formula (II): R7-CH=CH-R8; wherein R7 and R8 are the same or different and are independently selected from the group consisting of hydrogen, sulfonate, -CN, -CHO, and -COOR9, wherein R9 is selected from the group consisting of hydrogen, and an alkyl group, or R7 and R8 together form a –C(O)-O-(O)C- group or a –C(O)-NR10-C(O)- group, wherein R10 represents hydrogen, an aliphatic or an aromatic group, to produce an unsaturated bicyclic ether having an unsaturated carbon-carbon bond; (ii) hydrogenating the unsaturated carbon-carbon bond in the unsaturated bicyclic ether to produce a saturated bicyclic ether; and (iii) dehydrating and aromatizing the saturated bicyclic ether to produce the benzene compound.
- -
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Page/Page column 12
(2016/07/05)
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- ALCOHOL COMPOUND AND METHOD FOR PRODUCING SAME, METHOD FOR PRODUCING LACTONE COMPOUND, (METH)ACRYLATE ESTER AND METHOD FOR PRODUCING SAME, POLYMER AND METHOD FOR PRODUCING SAME, AND RESIST COMPOSITION AND METHOD FOR PRODUCING SUBSTRATE USING SAME
-
To provide an alcohol compound containing fewer impurities at a high yield by conducting the following steps: a hydroboration process in which a reaction mixture is obtained by reacting in a solvent a compound represented by formula (C) and a boron agent selected from a group of diborane and borane complexes; and an oxidation process in which the pH of the reaction mixture is set at 0.5 to 4, which is conducted after treating the reaction mixture with hydrogen peroxide. In the formula, A1 to A6 are each independently a hydrogen atom, methyl group or ethyl group, and X is an oxygen atom, sulfur atom, methylene group or ethylene group.
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Paragraph 0327-0329
(2016/12/16)
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- Unique norbornene based triazole molecule for selective Fe(II) sensing
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A triazole functionalized norbornene monomer (NFTZ) and its corresponding homopolymer (NFTZH) are synthesized. The unique fluorescence properties of the NFTZ molecule are due to the conjugation of two aromatic rings through an amide bond. The chelating behaviour of the NFTZ monomer is explored through the selective binding of Fe(ii) in the presence of other metals. The MALDI-TOF analysis and Job's plot clearly confirm the 1:2 mode of binding of NFTZ with Fe(ii). 1H NMR and IR spectroscopy clearly confirm the unique amide-iminol tautomerisation.
- Bhattacharya, Sourav,Shunmugam, Raja
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p. 74973 - 74976
(2015/09/21)
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- NANOPARTICLES FOR DRUG DELIVERY COMPRISING ALBUMIN HAVING A POLYMER CHAIN COUPLED THERETO
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The invention provides a dispersion of assemblies. The assemblies comprise an albumin derivative comprising albumin having a polymer chain coupled thereto, wherein the assemblies comprise a core comprising the polymer chains and a shell comprising the albumin. A process for making the dispersion and methods of using the dispersion are also described.
- -
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Paragraph 000130
(2014/10/18)
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- DENTAL MATERIALS BASED ON MONOMERS HAVING DEBONDING-ON-DEMAND PROPERTIES
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The invention relates to a dental restorative material which comprises a thermolabile or photolabile polymerizable compound of Formula I: [(Z1)m-Q1-X)]k-T-[Y-Q2-(Z2)n]1??Formula I, in which T represents a thermolabile or photolabile group, Z1 and Z2 in each case independently represent a polymerizable group selected from vinyl groups, CH2═CR1—CO—O— and CH2═CR1—CO—NR2— or an adhesive group selected from —Si(OR)3, —COOH, —O—PO(OH)2, —PO(OH)2, —SO2OH and —SH, wherein at least one Z1 or Z2 is a polymerizable group, Q1 in each case independently is missing or represents an (m+1)-valent linear or branched aliphatic C1-C20 radical which can be interrupted by —O—, —S—, —CO—O—, —O—CO—, —CO—NR3—, —NR3—CO—, —O—CO—NR3—, —NR3—CO—O— or —NR3—CO—NR3—, Q2 in each case independently is missing or represents an (n+1)-valent linear or branched aliphatic C1-C20 radical which can be interrupted by —O—, —S—, —CO—O—, —O—CO—, —CO—NR3—, —NR3—CO—, —O—CO—NR3—, —NR3—CO—O— or —NR3—CO—NR3—, X and Y in each case independently are missing or represent —O—, —S—, CO—O—, —O—CO—, —CO—NR3—, —NR3—CO—, —O—CO—NR3—, —NR3—CO—O— or —NR3—CO—NR3—, R, R1, R2 and R3 in each case independently represent H or a C1-C7 alkyl radical and k, l, m and n in each case independently are 1, 2 or 3.
- -
-
Paragraph 0141; 0142; 0143; 0144
(2014/11/13)
-
- Self-healing polyurethanes with shape recovery
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Two new thermoresponsive self-healing polyurethanes (1DA1T and 1.5DA1T) based on the Diels-Alder (DA) reaction between furan and maleimide moieties are developed that use the shape-memory effect to bring crack faces into intimate contact such that healing can take place. Unlike other self-healing polymers, these polymers do not require external forces to close cracks but rather they use the shape-memory effect to autonomously close the crack. Both polyurethanes have a stable polymer structure and comparable mechanical properties to commercial epoxies. A differential scanning calorimeter is employed to check the glass transition temperature of the polymers as well as the DA and retro-DA (rDA) reaction temperatures. These DA and rDA reactions are confirmed with variable-temperature proton nuclear magnetic resonance. Healing efficiency is calculated using a measurement of the failure load from compact tension testing. The results show that the shape-memory effect can replace external forces to close two crack surfaces and the DA reaction can be repeatedly employed to heal the cracks.
- Heo, Yunseon,Sodano, Henry A.
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p. 5261 - 5268,8
(2014/11/08)
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- Aarhus sensor green: A fluorescent probe for singlet oxygen
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A tetrafluoro-substituted fluorescein derivative covalently linked to a 9,10-diphenyl anthracene moiety has been synthesized, and its photophysical properties have been characterized. This compound, denoted Aarhus Sensor Green (ASG), has distinct advantages for use as a fluorescent probe for singlet molecular oxygen, O2(a1δg). In the least, ASG overcomes several limitations inherent to the use of the related commercially available product called Singlet Oxygen Sensor Green (SOSG). The functional behavior of both ASG and SOSG derives from the fact that these weakly fluorescent compounds rapidly react with singlet oxygen via a π2 + π4 cycloaddition to irreversibly yield a highly fluorescent endoperoxide. The principal advantage of ASG over SOSG is that, at physiological pH values, both ASG and the ASG endoperoxide (ASG-EP) do not themselves photosensitize the production of singlet oxygen. As such, ASG better fits the requirement of being a benign probe. Although ASG readily enters a mammalian cell (i.e., HeLa) and responds to the presence of intracellular singlet oxygen, its behavior in this arguably complicated environment requires further investigation.
- Pedersen, Stephan K.,Holmehave, Jeppe,Blaikie, Frances H.,Gollmer, Anita,Breitenbach, Thomas,Jensen, Henrik H.,Ogilby, Peter R.
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p. 3079 - 3087
(2014/05/06)
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- Thermoreversible reactions on inorganic nanoparticle surfaces: Diels-alder reactions on sterically crowded surfaces
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Organically surface-functionalized nanoparticles are important cross-linkers for nanocomposites. In the past, many cross-linking reactions were based on simple radical additions. However, novel smart materials require reversible reactions. These reactions, such as the Diels-Alder reaction, often have a specific sterical demand, e.g., a six-centered transition state. In this study, 5 nm silica particles were functionalized with maleimide groups, and their reactivity with regard to Diels-Alder reactions were investigated, applying various techniques. A new method for the surface modification of silica nanoparticles is presented, minimizing agglomeration in organic solvents and thus increasing the accessibility of the functional groups on the particle surface. Kinetic studies of substituted model compounds were carried out to evaluate the reactivity of the maleimide functionality. The Diels-Alder reaction between 2,5-dimethylfuran and N-propylmaleimide, N-ethyl(N-propylcarbamato) maleimide, and N-phenylmaleimide was followed by UV/Vis spectroscopy. The reaction rate increases in this order, showing the effect of maleimide substitution. Afterwards N-((3-triethoxysilyl)propyl)maleimide was used to graft maleimidopropyl functional groups onto the nanoparticle surface. 3-Aminopropyltriethoxysilane, which could then be reacted with 1,1′-(methylenedi-4,1-phenylene)bismaleimide, was used to attach phenyl-substituted maleimide functionality to the surface. 3- Isocyanatopropyltriethoxysilane introduced the electron-drawing carbamato functionality into the system. The surface coverage of the samples was characterized applying CHN analysis, TGA-FTIR coupling, and FTIR spectroscopy. All analytical methods revealed that the functional groups are covalently bonded to the silica surface and the maleimide rings remain intact. Diels-Alder reactions of the surface groups show that the reactivity of the molecules attached to the particles depends on sterical crowding, but the reaction rate is not significantly changed by surface effects.
- Engel, Tom,Kickelbick, Guido
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p. 149 - 157
(2013/08/24)
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