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1.
Hermann Schildknecht 《Angewandte Chemie (International ed. in English)》1981,20(2):164-184
All living organisms respond to stimulation, reacting more or less sensitively and more or less typically to a wide variety of energy forms such as light, heat, gravity, pressure (sound), electricity—and chemicals. A living organism responds to an irritation by releasing irritants which—as potential defense substances—are directed against the attacker or assist the organism endogenously in an intrinsic defense reaction. Often very small energy changes perceived by the plant are enough to induce a series of physiological processes ultimately manifested as a glandular reaction or even movement. The irritants involved in these processes act on membranes as defense substances in the presence of an attacker, or as endogenous factors in their own cellular environment. These chemically very diverse low-molecular active principles have been found in many parts of plants and in many plant families. For this reason alone we could speak of a chemical herbarium, but the case is even stronger because, in this botanical documentation, not only the individual chemicals are considered in context but also whole sets of interacting substances, since it is only in these sets that optimal activity is found (just as one considers not only the parts of a plant but also the whole plant in botany). 相似文献
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Thomas G. Minehan Yoshito Kishi 《Angewandte Chemie (International ed. in English)》1999,38(7):923-925
Four monocyclic precursors were assembled in the total synthesis of the proposed structure 1 - A of (+)-tolyporphin A O,O-diacetate (X=Ac). Comparison of the spectroscopic data demonstrated that synthetic tolyporphin O,O-diacetate did not match the O,O-diacetate prepared from natural (+)-tolyporphin A (X=H), calling for a structural revision of this class of natural products. On the basis of a series of NMR experiments including synthetic intermediates, the structure of tolyporphin A is concluded to be 1 - B , in which the configurations of quaternary centers C7 and C17 are opposite to those in the originally proposed structure. 相似文献
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K. C. Nicolaou Nareshkumar F. Jain Swaminathan Natarajan Robert Hughes Michael E. Solomon Hui Li Joshi M. Ramanjulu Masaru Takayanagi Alexandros E. Koumbis Toshikazu Bando 《Angewandte Chemie (International ed. in English)》1998,37(19):2714-2716
A triazene-based synthetic strategy for the construction of the complex biaryl ethers and a Suzuki coupling reaction were the key steps in the synthesis of precursor 1 of the aglycon of vancomycin, which already contains the complete skeleton of the target compound. The cleavage of the triazene unit from the D ring and the removal of the other protecting groups led to the aglycon of vancomycin. These strategies should be particularly valuable for the synthesis of other naturally occurring glycopeptide antibiotics and offer opportunities for the synthesis of combinatorial libraries of compounds of the vancomycin family for chemical biology studies. 相似文献
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K. C. Nicolaou Masaru Takayanagi Nareshkumar F. Jain Swaminathan Natarajan Alexandros E. Koumbis Toshikazu Bando Joshi M. Ramanjulu 《Angewandte Chemie (International ed. in English)》1998,37(19):2717-2719
A triazene-based synthetic strategy for the construction of the complex biaryl ethers and a Suzuki coupling reaction were the key steps in the synthesis of precursor 1 of the aglycon of vancomycin, which already contains the complete skeleton of the target compound. The cleavage of the triazene unit from the D ring and the removal of the other protecting groups led to the aglycon of vancomycin. These strategies should be particularly valuable for the synthesis of other naturally occurring glycopeptide antibiotics and offer opportunities for the synthesis of combinatorial libraries of compounds of the vancomycin family for chemical biology studies. 相似文献
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K. C. Nicolaou Swaminathan Natarajan Hui Li Nareshkumar F. Jain Robert Hughes Michael E. Solomon Joshi M. Ramanjulu Christopher N. C. Boddy Masaru Takayanagi 《Angewandte Chemie (International ed. in English)》1998,37(19):2708-2714
A triazene-based synthetic strategy for the construction of the complex biaryl ethers and a Suzuki coupling reaction were the key steps in the synthesis of precursor 1 of the aglycon of vancomycin, which already contains the complete skeleton of the target compound. The cleavage of the triazene unit from the D ring and the removal of the other protecting groups led to the aglycon of vancomycin. These strategies should be particularly valuable for the synthesis of other naturally occurring glycopeptide antibiotics and offer opportunities for the synthesis of combinatorial libraries of compounds of the vancomycin family for chemical biology studies. 相似文献
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Breakdown of Chlorophyll in Higher Plants—Phyllobilins as Abundant,Yet Hardly Visible Signs of Ripening,Senescence, and Cell Death 下载免费PDF全文
Prof. Dr. Bernhard Kräutler 《Angewandte Chemie (International ed. in English)》2016,55(16):4882-4907
Fall colors have always been fascinating and are still a remarkably puzzling phenomenon associated with the breakdown of chlorophyll (Chl) in leaves. As discovered in recent years, nongreen bilin‐type Chl catabolites are generated, which are known as the phyllobilins. Collaborative chemical‐biological efforts have led to the elucidation of the key Chl‐breakdown processes in senescent leaves and in ripening fruit. Colorless and largely photoinactive phyllobilins are rapidly produced from Chl, apparently primarily as part of a detoxification program. However, fluorescent Chl catabolites accumulate in some senescent leaves and in peels of ripe bananas and induce a striking blue glow. The structural features, chemical properties, and abundance of the phyllobilins in the biosphere suggest biological roles, which still remain to be elucidated. 相似文献
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Hedda Schrey Dr. Jana Backenköhler Dr. Herbert Kogler Dr. Markus Plaumann Prof. Dr. Peter Spiteller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10333-10341
(5S,6S)-Aminotenuazonic acid, a new 3-acyltetramic acid, related to the well-known mycotoxin tenuazonic acid has been isolated from fruiting bodies of Laccaria bicolor. Its structure was mostly established by analysis of its 2D NMR and HR-(+)-ESI-MS spectra. A total synthesis starting from N-Boc-l -isoleucine gave (5S,6S)-aminotenuazonic acid in 8 % yield over nine steps (67 % de). The key steps of the total synthesis are a light-initiated Hofmann–Löffler–Freytag radical chain reaction and a Dieckmann cyclisation. The relative and absolute configurations of the natural product were determined by comparison of its NMR and CD spectra with those of the corresponding enantiopure synthetic compounds. Metabolic profiling of crude extracts of different mushrooms showed that aminotenuazonic acid is present in all four of the investigated Laccaria species. Aminotenuazonic acid shows phytotoxic activities against the root and shoot growth of Lepidium sativum, Pinus sylvestris and Arabidopsis thaliana comparable to those of tenuazonic acid. 相似文献
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α-Methylene-γ-butyrolactones [dihydro-3-methylene-2(3H)furanones] constitute an important group of natural products and possess wide-ranging biological activities. Progress in the synthesis of the heterocycle and the classification of the synthetic methods are not only of practical interest, but also fundamentally important as a current example for the construction of an unusual 1,4-functionality distance and an α-substituted acrylic ester moiety which is susceptible to nucleophilic attack. 相似文献
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Sooheum Jo Jin-Hee Kim Jiyeon Lee Youngjun Park Jaebong Jang 《Molecules (Basel, Switzerland)》2022,27(23)
Cyclic peptides are one of the important chemical groups in the HDAC inhibitor family. Following the success of romidepsin in the clinic, naturally occurring cyclic peptides with a hydrophilic moiety have been intensively studied to test their function as HDAC inhibitors. Azumamides A-E, isolated from Mycale izuensis, are one of the powerful HDAC inhibitor classes. Structurally, azumamides A-E consist of three D-α-amino acids and unnatural β-amino acids such as 3-amino-2-methyl-5-nonenedioic acid-9-amide (Amnna) and 3-amino-2-methyl-5-nonenoic-1,9-diacid (Amnda). Moreover, azumamides have a retro-arrangement peptide backbone, unlike other naturally occurring cyclopeptide HDAC inhibitors, owing to the D-configuration of all residues. This review summarizes the currently available synthetic methods of azumamides A-E focusing on the synthesis of β-amino acids and macrocyclization. In addition, we overview the structure–activity relationship of azumamides A-E based on reported analogs. Collectively, this review highlights the potentiality of azumamides A-E as an HDAC inhibitor and provides further developmental insight into naturally occurring cyclic peptides in HDAC inhibition. 相似文献
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Miguel A. González 《Tetrahedron letters》2004,45(26):5039-5041
The first synthesis of 5-isopropenyl-3-methyl-cyclohex-2-enone, (isocarvone) (2), in enantiomerically pure form is reported. Both enantiomers of 2 can be produced by manipulation of carboxylic acid 5, which is available from R-(−)-carvone (1). These materials provide new chiral building blocks that could be used in total synthesis of natural products and related optically active compounds. 相似文献
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G. Snatzke 《Angewandte Chemie (International ed. in English)》1968,7(1):14-25
The principles of circular dichroism and of optical rotatory dispersion are described. Examples are given to illustrate the use of these methods for the determination of the configurations and conformations of natural and synthetic products. Some limitations of the octant rule are mentioned. 相似文献
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Omaezallene from Red Alga Laurencia sp.: Structure Elucidation,Total Synthesis,and Antifouling Activity 下载免费PDF全文
Dr. Taiki Umezawa Yuko Oguri Dr. Hiroshi Matsuura Shohei Yamazaki Masahiro Suzuki Erina Yoshimura Dr. Takeshi Furuta Dr. Yasuyuki Nogata Dr. Yukihiko Serisawa Dr. Kazuyo Matsuyama‐Serisawa Dr. Tsuyoshi Abe Prof. Dr. Fuyuhiko Matsuda Dr. Minoru Suzuki Dr. Tatsufumi Okino 《Angewandte Chemie (International ed. in English)》2014,53(15):3909-3912
Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene‐containing natural products isolated from the red alga Laurencia sp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated. 相似文献
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Jenny Barbier Dr. Rolf Jansen Dr. Herbert Irschik Dr. Stefan Benson Dr. Klaus Gerth Bettina Böhlendorf Prof. Dr. Gerhard Höfle Prof. Dr. Hans Reichenbach Jens Wegner Dr. Carsten Zeilinger Prof. Dr. Andreas Kirschning Prof. Dr. Rolf Müller 《Angewandte Chemie (International ed. in English)》2012,51(25):6035-6035
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Chrysoxanthone, an unusual heterodimer of blennolide A and 2-hydroxychrysophanol linked through a diaryl ether bridge, was isolated from mycelia of the ascomycete IBWF11-95A grown in submerged culture. Its structure was elucidated by two-dimensional NMR spectroscopy. The metabolite shows antibacterial activity against different species with MIC values between 2.5 and 20 μg/mL while also inhibiting the growth of several fungi. 相似文献