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Conformation‐Enabled Total Syntheses of Ohmyungsamycins A and B and Structural Revision of Ohmyungsamycin B 下载免费PDF全文
Joonseong Hur Dr. Jaebong Jang Dr. Jaehoon Sim Prof. Dr. Woo Sung Son Prof. Dr. Hee‐Chul Ahn Dr. Tae Sung Kim Yern‐Hyerk Shin Dr. Changjin Lim Dr. Seungbeom Lee Dr. Hongchan An Prof. Dr. Seok‐Ho Kim Prof. Dr. Dong‐Chan Oh Prof. Dr. Eun‐Kyeong Jo Prof. Dr. Jichan Jang Prof. Dr. Jeeyeon Lee Prof. Dr. Young‐Ger Suh 《Angewandte Chemie (International ed. in English)》2018,57(12):3069-3073
The first total syntheses of the bioactive cyclodepsipeptides ohmyungsamycin A and B are described. Key features of our synthesis include the concise preparation of a linear cyclization precursor that consists of N‐methyl amides and non‐proteinogenic amino acids, and its macrolactamization from a bent conformation. The proposed structure of ohmyungsamycin B was revised based on its synthesis. The cyclic core of the ohmyungsamycins was shown to be responsible for the excellent antituberculosis activity, and ohmyungsamycin variants with truncated chains were evaluated for their biological activity. 相似文献
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Synthesis of Sulfotyrosine‐Containing Peptides by Incorporating Fluorosulfated Tyrosine Using an Fmoc‐Based Solid‐Phase Strategy 下载免费PDF全文
Wentao Chen Dr. Jiajia Dong Dr. Suhua Li Dr. Yu Liu Dr. Yujia Wang Leonard Yoon Dr. Peng Wu Dr. K. Barry Sharpless Dr. Jeffery W. Kelly 《Angewandte Chemie (International ed. in English)》2016,55(5):1835-1838
Tyrosine O‐sulfation is a common protein post‐translational modification that regulates many biological processes, including leukocyte adhesion and chemotaxis. Many peptides with therapeutic potential contain one or more sulfotyrosine residues. We report a one‐step synthesis for Fmoc‐fluorosulfated tyrosine. An efficient Fmoc‐based solid‐phase peptide synthetic strategy is then introduced for incorporating the fluorosulfated tyrosine residue into peptides of interest. Standard simultaneous peptide‐resin cleavage and removal of the acid‐labile side‐chain protecting groups affords the crude peptides containing fluorosulfated tyrosine. Basic ethylene glycol, serving both as solvent and reactant, transforms the fluorosulfated tyrosine peptides into sulfotyrosine peptides in high yield. 相似文献
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Weilong Liu Houhua Li Pei‐Jun Cai Zhen Wang Prof. Dr. Zhi‐Xiang Yu Prof. Dr. Xiaoguang Lei 《Angewandte Chemie (International ed. in English)》2016,55(9):3112-3116
Reported is the first scalable synthesis of rac‐jungermannenones B and C starting from the commercially available and inexpensive geraniol in 10 and 9 steps, respectively. The unique jungermannenone framework is rapidly assembled by an unprecedented regioselective 1,6‐dienyne reductive cyclization reaction which proceeds through a vinyl radical cyclization/allylic radical isomerization mechanism. DFT calculations explain the high regioselectivity observed in the 1,6‐dienyne reductive radical cyclization. 相似文献
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Dr. Simon Gregersen Prof. Dr. Tom Vosch Prof. Dr. Knud J. Jensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18492-18500
Few‐atom silver nanoclusters (AgNCs) can exhibit strong fluorescence; however, they require ligands to prevent aggregation into larger nanoparticles. Fluorescent AgNCs in biopolymer scaffolds have so far mainly been synthesized in solution, and peptides have only found limited use compared to DNA. Herein, we demonstrate how solid‐phase methods can increase throughput dramatically in peptide ligand screening and in initial evaluation of fluorescence intensity and chemical stability of peptide‐stabilized AgNCs (P‐AgNCs). 9‐Fluorenylmethyloxycarbonyl (Fmoc) solid‐phase peptide synthesis on a hydroxymethyl‐benzoic acid (HMBA) polyethylene glycol polyacrylamide copolymer (PEGA) resin enabled on‐resin screening and evaluation of a peptide library, leading to identification of novel peptide‐stabilized, fluorescent AgNCs. Using systematic amino acid substitutions, we synthesized and screened a 144‐member library. This allowed us to evaluate the effect of length, charge, and Cys content in peptides used as ligands for AgNC stabilization. The results of this study will enable future spectroscopic studies of these peptide‐stabilized AgNCs for bioimaging and other applications. 相似文献
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Philipp Waser Karl‐Heinz Altmann 《Angewandte Chemie (International ed. in English)》2020,59(40):17393-17397
The total synthesis of the potent new antibiotic disciformycin B ( 2 ) is described, which shows significant activity against methicillin‐ and vancomycin‐resistant Staphylococcus aureus (MRSA/VRSA) strains. The synthetic route is based on macrocyclization of a tetraene substrate to the 12‐membered macrolactone core by ring‐closing olefin metathesis (RCM). Although macrocyclization was accompanied by concomitant cyclopentene formation by an alternative RCM pathway, conditions were established to give the macrocycle as the major product. Key steps in the construction of the RCM substrate include a highly efficient Evans syn‐aldol reaction, the asymmetric Brown allylation of angelic aldehyde, and the stereoselective Zn(BH4)2‐mediated 1,2‐reduction of an enone. The synthesis was completed by late‐stage dehydrative glycosylation to introduce the d ‐arabinofuranosyl moiety and final chemoselective allylic alcohol oxidation. 相似文献
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Haoxuan Wang Prof. Sarah E. Reisman 《Angewandte Chemie (International ed. in English)》2014,53(24):6206-6210
The concise total syntheses of the bis(pyrroloindolines) (?)‐lansai B and (+)‐ nocardioazines A and B are reported. The key pyrroloindoline building blocks are rapidly prepared by enantioselective formal [3+2] cycloaddition reactions. The macrocycle of (+)‐nocardioazine A is constructed by an unusual intramolecular diketopiperazine formation. 相似文献
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Sheng Guo Jie Liu Prof. Dr. Dawei Ma 《Angewandte Chemie (International ed. in English)》2015,54(4):1298-1301
Leucosceptroids A and B are sesterterpenoids with potent antifeedant and antifungal activities. A more efficient gram‐scale total synthesis of leucosceptroid B and the first total synthesis of leucosceptroid A are presented. The key transformations include an aldol reaction between a substituted dihydrofuranone and an (S)‐citronellal‐derived aldehyde, a SmI2‐mediated intramolecular ketyl–olefin radical cyclization, and final‐stage alcohol oxidation. 相似文献
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Liang Wang Hengtao Wang Yihang Li Prof. Dr. Pingping Tang 《Angewandte Chemie (International ed. in English)》2015,54(19):5732-5735
The first total syntheses of schilancitrilactones B and C have been accomplished in 17 steps (longest linear sequence) from commercially available materials. Key steps include an intramolecular radical cyclization to provide the seven‐membered ring, late‐stage iodination, and an intermolecular radical addition reaction to complete the total synthesis. 相似文献
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Total Syntheses of Linear Polythiazole/Oxazole Plantazolicin A and Its Biosynthetic Precursor Plantazolicin B 下载免费PDF全文
Dr. Zoe E. Wilson Dr. Sabine Fenner Prof. Steven V. Ley 《Angewandte Chemie (International ed. in English)》2015,54(4):1284-1288
Plantazolicin A, a linear decacyclic natural product, exhibits desirable selective activity against the causative agent of anthrax toxicity. The total synthesis of plantazolicin A and its biosynthetic precursor plantazolicin B was successfully achieved by an efficient, unified, and highly convergent route featuring dicyclizations to form 2,4‐concatenated oxazoles and the mild synthesis of thiazoles from natural amino acids. This report represents the first synthesis of plantazolicin B and includes the first complete characterization data for both natural products. 相似文献
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Quaternary β2,2‐Amino Acids: Catalytic Asymmetric Synthesis and Incorporation into Peptides by Fmoc‐Based Solid‐Phase Peptide Synthesis 下载免费PDF全文
Dr. Jin‐Sheng Yu Dr. Hidetoshi Noda Prof. Dr. Masakatsu Shibasaki 《Angewandte Chemie (International ed. in English)》2018,57(3):818-822
β‐Amino acid incorporation has emerged as a promising approach to enhance the stability of parent peptides and to improve their biological activity. Owing to the lack of reliable access to β2,2‐amino acids in a setting suitable for peptide synthesis, most contemporary research efforts focus on the use of β3‐ and certain β2,3‐amino acids. Herein, we report the catalytic asymmetric synthesis of β2,2‐amino acids and their incorporation into peptides by Fmoc‐based solid‐phase peptide synthesis (Fmoc‐SPPS). A quaternary carbon center was constructed by the palladium‐catalyzed decarboxylative allylation of 4‐substituted isoxazolidin‐5‐ones. The N?O bond in the products not only acts as a traceless protecting group for β‐amino acids but also undergoes amide formation with α‐ketoacids derived from Fmoc‐protected α‐amino acids, thus providing expeditious access to α‐β2,2‐dipeptides ready for Fmoc‐SPPS. 相似文献
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K. C. Nicolaou Prof. Dr. Yefeng Tang Dr. Jianhua Wang 《Angewandte Chemie (International ed. in English)》2009,48(19):3449-3453
An ocean of discovery : The first total synthesis of the highly oxygenated, marine‐derived, natural product sporolide B has been achieved through a convergent strategy. The key steps involve a ruthenium‐catalyzed [2+2+2] cycloaddition to assemble the indene structural motif and a thermally induced Diels–Alder‐type reaction to forge the macrocycle (see scheme).
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Divergent Solid‐Phase Synthesis of Natural Product‐Inspired Bipartite Cyclodepsipeptides: Total Synthesis of Seragamide A 下载免费PDF全文
Prof. Dr. Hans‐Dieter Arndt Dr. Stefano Rizzo M. Sc. Christina Nöcker Dr. Vijay N. Wakchaure Dr. Lech‐Gustav Milroy B. Sc. Vanessa Bieker Dr. Abram Calderon Dr. Tuyen T. N. Tran Dr. Silke Brand Dr. Leif Dehmelt Prof. Dr. Herbert Waldmann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5311-5316
Macrocyclic natural products (NPs) and analogues thereof often show high affinity, selectivity, and metabolic stability, and methods for the synthesis of NP‐like macrocycle collections are of major current interest. We report an efficient solid‐phase/cyclorelease method for the synthesis of a collection of macrocyclic depsipeptides with bipartite peptide/polyketide structure inspired by the very potent F‐actin stabilizing depsipeptides of the jasplakinolide/geodiamolide class. The method includes the assembly of an acyclic precursor chain on a polymeric carrier, terminated by olefins that constitute complementary fragments of the polyketide section and cyclization by means of a relay‐ring‐closing metathesis (RRCM). The method was validated in the first total synthesis of the actin‐stabilizing cyclodepsipeptide seragamide A and the synthesis of a collection of structurally diverse bipartite depsipeptides. 相似文献
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