scholarly journals Elucidation of the relative and absolute stereochemistry of the kalimantacin/batumin antibiotics

2017 ◽  
Vol 8 (9) ◽  
pp. 6196-6201 ◽  
Author(s):  
Iain R. G. Thistlethwaite ◽  
Freya M. Bull ◽  
Chengsen Cui ◽  
Paul D. Walker ◽  
Shu-Shan Gao ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Natural Product ◽  
Multidisciplinary Approach ◽  
Product Degradation ◽  
Absolute Stereochemistry

A multidisciplinary approach combining natural product degradation, fragment synthesis, bioinformatics and NMR spectroscopy was used.

scholarly journals Synthetic study of ravidomycin, a hybrid natural product

2000 ◽  
Vol 72 (9) ◽  
pp. 1783-1786 ◽  
Author(s):  
Keisuke Suzuki
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Amino Sugar ◽  
Antitumor Antibiotics ◽  
Ready Availability ◽  
Silyl Acetals ◽  
Gilvocarcin V ◽  
Absolute Stereochemistry

Strategies and tactics associated with the total synthesis of hybrid natural products are discussed. The target is ravidomycin (2), one of the gilvocarcin-class antitumor antibiotics with an aryl C-glycoside structure. The first total synthesis of 2, which was achieved along similar lines of that of gilvocarcin V (1), served for the determination of the relative as well as the absolute stereochemistry of 2. Also revealed was a limitation of the synthetic scheme so long as the amino sugar congener was concerned. A preliminary result is discussed on the [2+2+2] approach that relies on the ready availability of various benzocyclobutene derivatives via regioselective [2+2] cycloaddition of α-alkoxybenzynes and ketene silyl acetals.

Total synthesis of antiallergic bicyclic peptide seongsanamide A

2020 ◽  
Vol 7 (13) ◽  
pp. 1658-1662
Author(s):  
Feipeng Han ◽  
Yian Guo ◽  
Tao Ye
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Absolute Stereochemistry

The first total synthesis of antiallergic depsipeptide seongsanamide A has been achieved and also the relative and absolute stereochemistry of the natural product has been confirmed.

scholarly journals Investigations into the H-D Exchange of Malonganenone B

2021 ◽  
Author(s):  
◽  
Peter G K Clark
Keyword(s):  
Nmr Spectroscopy ◽  
Natural Product ◽  
Silver Oxide ◽  
Kinetic Studies ◽  
Acid Inhibition ◽  
First Order ◽  
Exchange Kinetic ◽  
Synthetic Studies

<p>H-D exchange at the formyl residue of the natural product malonganenone B was investigated. Models of the system were synthesised and displayed the same exchange. Kinetic studies, performed using NMR spectroscopy, found the exchange was first order with respect to base whilst displaying acid inhibition, in opposition to existing research. Cyclic species, including an N-heterocyclic carbene precursor, were formed that, in conjunction with the previous findings, suggested a carbene-based mechanism was in operation. Further synthetic studies were performed to demonstrate the existence of a carbene. With use of silver oxide, a fulvalene dimer and an organopalladium complex of this carbene were obtained, which provide further support towards a carbene-based mechanism being involved in the H-D exchange of malonganenone B.</p>

Two for One: Structure Revision of the Marine Sesterterpene Tetronic Acid Strobilinin to (8Z,13E,20Z)-Strobilinin and (8E,13Z,20Z)-Strobilinin

1994 ◽  
Vol 47 (5) ◽  
pp. 933 ◽  
Author(s):  
R Davis ◽  
RJ Capon
Keyword(s):  
Natural Product ◽  
Spectroscopic Analysis ◽  
Marine Natural Product ◽  
Geometric Isomers ◽  
Tetronic Acid ◽  
Naturally Occurring ◽  
Structure Revision ◽  
Single Compound ◽  
The Absolute ◽  
Absolute Stereochemistry

A reinvestigation of the known marine natural product strobilinin has revealed it not to be a single compound (2), but to consist of two naturally occurring geometric isomers, neither of which corresponds to the structure originally assigned. These isomers, (8E,13Z,20Z)- strobilinin (10) and (8Z,13E,20Z)-strobilinin (11), were resolved, characterized and identified as their respective acetate derivatives (6) and (7), and their structures assigned by spectroscopic analysis. It would appear that the absolute stereochemistry of the strobilinins is very likely opposite to that of co-occurring variabilin (1).

scholarly journals New and old challenges in total synthesis. From concept to practice

2003 ◽  
Vol 75 (2-3) ◽  
pp. 209-221 ◽  
Author(s):  
S. Hanessian ◽  
Roberto Margarita ◽  
Adrian Hall ◽  
Shawn Johnstone ◽  
M. Tremblay ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Marine Natural Products ◽  
Stereocontrolled Synthesis ◽  
Absolute Stereochemistry

The total synthesis of dysinosin A, a novel member of the aeruginosin group of marine natural products is discussed. The stereocontrolled synthesis also confirms the proposed structure and absolute stereochemistry of the natural product.

scholarly journals New Kendomycin Derivative Isolated from Streptomyces sp. Cl 58-27

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6834
Author(s):  
Constanze Paulus ◽  
Oleksandr Gromyko ◽  
Andriy Luzhetskyy
Keyword(s):  
Nmr Spectroscopy ◽  
Natural Product ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Streptomyces Sp ◽  
Bioinformatic Tools ◽  
Isolation And Characterization ◽  
Metabolism Gene

In the course of screening new streptomycete strains, the strain Streptomyces sp. Cl 58-27 caught our attention due to its interesting secondary metabolite production profile. Here, we report the isolation and characterization of an ansamycin natural product that belongs structurally to the already known kendomycins. The structure of the new kendomycin E was elucidated using NMR spectroscopy, and the corresponding biosynthetic gene cluster was identified by sequencing the genome of Streptomyces sp. Cl 58-27 and conducting a detailed analysis of secondary metabolism gene clusters using bioinformatic tools.

scholarly journals Revisiting marine bioprospecting of tropical Indonesian macroalgae from West Timor

2021 ◽  
Author(s):  
◽  
Wem Turupadang
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Natural Product ◽  
Marine Algae ◽  
Liquid Chromatography Mass Spectrometry ◽  
Molecular Networking ◽  
West Timor

<p>Marine algae are an important and historically rich source of new marine-based natural products. This thesis describes the screening of 40 Indonesian macroalgal samples using liquid chromatography-mass spectrometry (LC-MS) based molecular networking, and the subsequent nuclear magnetic resonance (NMR)-guided isolation and structural elucidation of a 6-deoxy-6-aminoglycoglyrecolipid (60). Molecular networking was performed using LC-MS/MS data through the online Global Natural Product Social Molecular Networking (GNPS) platform directly from crude extracts. NMR spectroscopy-guided screening was also employed targeting unique peaks detected by 1H NMR to validate any hits from GNPS. Out of 40 macroalgae specimens collected from West Timor waters, six samples were prioritised by the molecular networking screening. Proton NMR revealed three specimens with significantly interesting peaks but only one specimen, Laurencia snackeyi was purified further, which yielded compound 60.</p>

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