- COLLECTIONS OF PEPTIDES, PEPTIDE AGENTS, AND METHODS OF USE THEREOF
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The present disclosure provides powerful technologies for the development, production, characterization, and/or use of stapled peptide compositions. Among other things, the present disclosure provides strategies for defining amino acid sequences particularly amenable or useful for stapling, as well as technologies, reagents, and systems for developing, producing, characterizing, and/or using stapled peptides having such amino acid sequences.
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Paragraph 0360-0361
(2020/03/15)
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- Exploration of the Photodegradation of Naphtho[2,3-g] quinoxalines and Pyrazino[2,3-b]phenazines
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Nitrogen-containing polycyclic aromatic hydrocarbons are very attractive compounds for organic electronics applications. Their low-lying LUMO energies points towards a potential use as n-type semiconductors. Furthermore, they are expected to be more stable under ambient conditions, which is very important for the formation of semiconducting films, where materials with high purity are needed. In this study, the syntheses of naphtho[2,3-g]quinoxalines and pyrazino[2,3-b]phenazines is presented by using reaction conditions, that provide the desired products in high yields, high purity and without time-consuming purification steps. The HOMO and LUMO energies of the compounds are investigated by cyclic voltammetry and UV/Vis spectroscopy and their dependency on the nitrogen content and the terminal substituents are examined. The photostability and the degradation pathways of the naphtho[2,3-g]quinoxalines and pyrazino[2,3-b]phenazines are explored by NMR spectroscopy of irradiated samples affirming the large influence of the nitrogen atoms in the acene core on the degradation process during the irradiation. Finally, by identifying the degradations products of 2,3-dimethylnaphtho[2,3-g]quinoxaline it is possible to track down the most reactive position in the compound and, by blocking this position with nitrogen, to strongly increase the photostability.
- Kolmer-Anderl, Nicole,Kolmer, Andreas,Thiele, Christina M.,Rehahn, Matthias
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supporting information
p. 5277 - 5287
(2016/04/09)
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- Total syntheses of the dipyrrolobenzoquinone (+)-terreusinone enabled by an evaluation of 4-methylpent-1-yn-3-ols in the Larock indole synthesis
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The Larock indolization between 4-methylpent-1-yn-3-ols (alkynols) and ortho-bromo and ortho-iodoanilines has been studied. Although the unprotected alkynol was an unviable substrate for the annulation reaction, protected derivatives did proceed to the indole products. Interestingly, this reaction does not appear to occur by the widely accepted mechanism for the Larock indolization of internal alkynes, but by the initial formation of a cross-coupled arylalkyne followed by 5-endo-dig cyclization. Importantly, when a chiral alkynol is used, the stereochemical integrity is retained in the indole product. Although this methodology could not be successfully extended to a double Larock indolization approach to terreusinone, two separate total syntheses evolved from these studies: A bidirectional, double Sonogashira-hydroamination approach and a one-pot Larock indolization- Sonogashira coupling followed by hydroamination. This work has not only confirmed the gross structure and absolute configuration of the photoprotecting natural product terreusinone, but also uncovered several novel applications of known reaction conditions that should find broad applications in the field of heteroaromatic construction.
- Wang, Christy,Sperry, Jonathan
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p. 4563 - 4577
(2013/06/27)
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- Hydrogen bonded arylamide-linked cholesteryl dimesogenic liquid crystals: A study of the length and side chain effects
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Dimesogenic compounds 1a-c, 2a-i, and 3, that are composed of a hydrogen bonding-induced straight arylamide spacer and two appended cholesterol groups, have been designed and synthesized. The backbones of the rigid spacers of 1a-c, 2a-i, and 3 contain one, three, and five benzene units, which bear two, six, and ten alkoxyl (methoxyl, n-octoxyl, or n-dodecoxyl) groups, respectively. The thermal and optical properties of the compounds are investigated by using the differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (PXRD) analysis. It is revealed that 1a-c exhibit one or two liquid crystalline (LC) phases, 2a-i exhibit no, one or two LC phases, while 3 exhibits one LC phase in a wide temperature range. Generally, the more and longer alkoxyl chains facilitate the formation of the LC phases at low temperature. Notably, compound 2g, which bears two methoxyl and four dodecoxyl groups, displays a blue-red color change during both the heating and cooling cycle. The result illustrates that dimesogens with large rigid spacers can exhibit different LC phases when long aliphatic chains are appended to balance the strong stacking of the rigid backbones.
- Wang, Gui-Tao,Zhao, Xin,Li, Zhan-Ting
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- Design, synthesis, and cytotoxicity of indolizinoquinoxaline-5,12-dione derivatives, novel DNA topoisomerase IB inhibitors
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A series of new indolizinoquinoxaline-5,12-dione derivatives were designed and synthesized via a heterocyclization reaction of 6,7-dichloroquinoxaline-5,8- dione with active methylene reagents and pyridine derivatives. The synthesized compounds exhibited significant activity to inhibit the growth of four human tumour cell lines, including lung adenocarcinoma cell, large-cell lung carcinoma cell, breast carcinoma cell, and ardriamycin-resistant breast carcinoma cell at micromolar range. These compounds were also investigated for their inhibition to DNA topoisomerase IB activity. The results indicated that the indolizinoquinoxaline-5,12-dione structure might be a potential pharmacophore in anti-cancer drug design.
- Shen, De-Qing,Wu, Ning,Li, Yan-Ping,Wu, Zu-Ping,Zhang, Hong-Bin,Huang, Zhi-Shu,Gu, Lian-Quan,An, Lin-Kun
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experimental part
p. 1116 - 1121
(2011/03/21)
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- Dynamic [2]catenanes based on a hydrogen bonding-mediated bis-zinc porphyrin foldamer tweezer: A case study
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(Chemical Equation Presented) This paper describes the self-assembly of a new class of three-component dynamic [2]catenanes, which are driven or stabilized by intramolecular hydrogen bonding, coordination, and electrostatic interaction. One of the component molecules 2, consisting of an aromatic oligoamide spacer and two peripheral zinc porphyrin units, was designed to adopt a folded preorganized conformation, which is stabilized by consecutive intramolecular three-centered hydrogen bonds. Component molecule 3 is a linear secondary ammonium bearing two peripheral pyridine units, which was designed to form a 1:1 complex with 24-crown-8 (5). The 1H NMR and UV-vis experiments in CDCl3-CD3CN (4:1 v/v) revealed that, due to the preorganized U-shaped feature, 2 could efficiently bind 3 through the cooperative zinc-pyridine coordination to generate highly stable 1:1 complex 2·3. Adding 5 to the 1:1 solution of 2 and 3 led to the formation of dynamic three-component [2]catenane 2·3·5 as a result of the threading of 3 through 5. 1H NMR studies indicated that in the 1:1:1 solution (3 mM) [2]catenane 2·3·5 was generated in 55% yield at 25°C. The yield was increased with the reduction of the temperature and [2]catenane could be produced quantitatively in a 1:1:2 solution ([2] = 3 mM) at -13°C. Replacing 3 with 1,2-bis(4,4′-bipyridinium)ethane (4) in the three-component solution could also give rise to similar dynamic [2]-catenane 2·4·5 albeit in slightly lower yield.
- Wu, Jing,Fang, Fang,Lu, Wen-Ya,Hou, Jun-Li,Li, Chuang,Wu, Zong-Quan,Jiang, Xi-Kui,Li, Zhan-Ting,Yu, Yi-Hua
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p. 2897 - 2905
(2008/02/02)
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- Reaction of 2,5-dimethylpyrroles with quinones. Synthesis of new pyrrolylquinones dyes
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The reaction of 1,4-naphthoquinone (1) with 2,5-dimethylpyrroles (7a-7d) gives only 3-(1,4-naphthoquinonyl)-2,5-dimethylpyrroles. Extending the reaction to other quinones: 5-hydroxy-1,4-naphthoquinone (2), 1,2-naphthoquinone (3), quinoline-5,8-dione (4) and quinoxaline-5,8-dione (5), of which nothing was known, allows the synthesis of new pyrrolylquinones.
- Lion, Claude,Baudry, Richard,Hedayatullah, Mir,Da Conceicao, Louis,Genard, Sylvie,Maignan, Jean
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p. 125 - 130
(2007/10/03)
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- Photoinduced charge separation involving an unusual double electron transfer mechanism in a donor-bridge-acceptor molecule
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A series of rodlike donor-bridge-acceptor (D-B-A) molecules was synthesized to study the role of bridge energy levels on electron transfer (ET) rates. In these compounds, a 4-aminonaphthalene-1,8-imide (ANI) electron donor is linked to a 1,8:4,5-naphthalenediimide acceptor (NI) via the 1,4 positions on a phenyl bridge. The phenyl bridge is substituted at the 2 and 5 positions with methyl or methoxy groups to yield ANI-diMe-NI and ANI-diMeO-NI. These molecules differ only in the energy levels of the bridge molecular orbitals. Other parameters affecting ET rates such as donor-acceptor distance, orientation, and driving force are constant between the two systems. The rate constants for charge separation (CS) and charge recombination (CR) within ANI-diMeO-NI in toluene are 32 and 1400 times larger, respectively, than the corresponding rate constants for ANI-diMe-NI. Solvents of higher polarity diminish these differences in rate constants, making them comparable to those observed for ANI-diMe-NI. The relative energies of the ion pair states suggest that it is possible for the reaction 1*D-B-A → D-B+-A- to occur via a double electron-transfer process that is somewhat analogous to Dexter energy transfer. The lowest excited singlet state of the donor, 1*ANI, possesses about 70% charge-transfer character, so that significant positive charge is localized on its amine nitrogen, whereas significant negative charge is localized on its naphthalene-1,8-imide ring. Electron transfer from the naphthalene-1,8-imide ring of 1*ANI to NI is concomitant with electron transfer from the p-dimethoxybenzene bridge to the electron-deficient amine nitrogen atom in 1*ANI. A series of reference molecules in which the p-dimethoxybenzene bridge moiety is attached only to ANI or NI alone is used to establish the structural and electronic requirements for this unusual charge separation mechanism.
- Miller, Scott E.,Lukas, Aaron S.,Marsh, Emily,Bushard, Patrick,Wasielewski, Michael R.
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p. 7802 - 7810
(2007/10/03)
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- Triazinyl reactive dyestuffs in which triazinyl group is further substituted with a beta-chloroethylsulfonyl- or vinylsulfonylbutyrylamino moiety
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Reactive dyes of the formula STR1 in which D is the radical of an organic dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthrone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or substituted or unsubstituted C1-4 -alkyl, X is a substituent which is detachable as an anion, B is a radical of the formula STR2 R1 and R2, independently of each other, are hydrogen or substituted or unsubstituted C1-4 -alkyl or phenyl, A is a substituted or unsubstituted aliphatic or aromatic bridge member, Y is a --CO--Z or --SO2 --Z radical, Z is an aliphatic, aromatic or heterocyclic reactive radical, and n is 1 or 2, are suitable for dyeing or printing cellulose-containing and nitrogen-containing materials and in high dyeing yield produce dyeings and prints having good fastness properties.
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