Synthesis of the 8-Deoxy Analogue of 4,9-Anhydro-10-hemiketal-5-deoxy-tetrodotoxin, a Proposed Biosynthetic Precursor of Tetrodotoxin

2021 ◽  
Author(s):  
Tadachika Miyasaka ◽  
Masaatsu Adachi ◽  
Toshio Nishikawa
Keyword(s):  
Biosynthetic Precursor

Synthesis and Reactivity of Precolibactin 886

2019 ◽  
Author(s):  
Seth Herzon ◽  
Alan R. Healy ◽  
kevin wernke ◽  
Chung Sub Kim ◽  
Nicholas Lees ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Gene Cluster ◽  
Amino Alcohol ◽  
Biomimetic Synthesis ◽  
Cross Linking ◽  
E Coli ◽  
Hplc Purification ◽  
Structural Assignment ◽  
Biosynthetic Precursor ◽  
Double Oxidation

<div>The clb gene cluster encodes the biosynthesis of metabolites known as precolibactins and colibactins. The clb pathway is found in gut commensal E. coli, and clb metabolites are thought to initiate colorectal cancer via DNA cross-linking. Precolibactin 886 (1) is one of the most complex isolated clb metabolites; it contains a 15-atom macrocycle and an unusual 5-hydroxy-3-oxazoline ring. Here we report confirmation of the structural assignment via a biomimetic synthesis of precolibactin 886 (1) proceeding through the amino alcohol 9. Double oxidation of 9 afforded the unstable α-ketoimine 2 which underwent macrocyclization to precolibactin 886 (1) upon HPLC purification (3% from 9). Studies of the putative precolibactin 886 (1) biosynthetic precursor 2, the model α-ketoimine 25, and the α-dicarbonyl 26 revealed that these compounds are susceptible to nucleophilic rupture of the C36–C37 bond. Moreover, cleavage of 2 produces other known clb metabolites or biosynthetic intermediates. This unexpected reactivity explains the difficulties in isolating full clb metabolites and accounts for the structure of a recently identified colibactin–adenine adduct. The colibactin peptidase ClbP deacylates synthetic precolibactin 886 (1) to form a non-genotoxic pyridone, suggesting precolibactin 886 (1) lies off-path of the major biosynthetic route.</div>

scholarly journals Inside Cover: Massadine Chloride: A Biosynthetic Precursor of Massadine and Stylissadine (Angew. Chem. Int. Ed. 35/2007)

2007 ◽  
Vol 46 (35) ◽  
pp. 6560-6560
Author(s):  
Achim Grube ◽  
Stefan Immel ◽  
Phil S. Baran ◽  
Matthias Köck
Keyword(s):  
Biosynthetic Precursor

ChemInform Abstract: Synthesis of Phenylacetyl-L-cysteinyl-D-valine Disulfide. A Biosynthetic Precursor of Penicillin G.

ChemInform ◽  
1989 ◽  
Vol 20 (24) ◽  
Author(s):  
J. M. LUENGO ◽  
M. T. ALEMANY ◽  
M. J. ARIN ◽  
M. T. DIEZ ◽  
F. SALTO
Keyword(s):  
Penicillin G ◽  
Biosynthetic Precursor

ChemInform Abstract: Synthesis of 4-Amino 3,4-Dideoxy-D-arabino-Heptulosonic Acid 7- Phosphate, the Biosynthetic Precursor of C7N Units in Ansamycin Antibiotics.

ChemInform ◽  
2010 ◽  
Vol 25 (32) ◽  
pp. no-no
Author(s):  
A. KIRSCHNING ◽  
P. BERGON ◽  
J.-J. WANG ◽  
S. BREAZEALE ◽  
H. G. FLOSS
Keyword(s):  
Biosynthetic Precursor

scholarly journals Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for the Enantioselective Total Synthesis of Mavacuran Alkaloids

2019 ◽  
Author(s):  
Maxime Jarret ◽  
Victor Turpin ◽  
Aurélien Tap ◽  
Jean-Francois Gallard ◽  
Cyrille Kouklovsky ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Oxidative Coupling ◽  
Indole Alkaloids ◽  
Oxidative Cyclization ◽  
Total Syntheses ◽  
Enantioselective Total Synthesis ◽  
Biosynthetic Precursor ◽  
Monoterpene Indole Alkaloids ◽  
Coupling Approach

We report the enantioselective total syntheses of mavacurans alkaloids, (+)-taberdivarine H, (+)-16-hydoxymethyl-pleiocarpamine, (+)-16-epi-pleiocarpamine, and their postulated biosynthetic precursor 16-formyl-pleiocarpamine. This family of monoterpene indole alkaloids is a target of choice since some of its members are subunits of intricate bisindole alkaloids such as bipleiophylline. Inspired by the biosynthetic hypothesis, we explored an oxidative coupling approach from the geissoschizine framework to form the N1-C16 bond. Quaternization of the aliphatic nitrogen was key to achieve the oxidative coupling induced by KHMDS/I<sub>2 </sub>since<sub> </sub>it hides the nucleophilicity of the aliphatic nitrogen and locks the required cis conformation.

Evidence that the immediate biosynthetic precursor of clavulanic acid is its N-aldehyde analogue

1994 ◽  
pp. 1281 ◽  
Author(s):  
Neville H. Nicholson ◽  
Keith H. Baggaley ◽  
Robert Cassels ◽  
Mark Davison ◽  
Stephen W. Elson ◽  
...  
Keyword(s):  
Clavulanic Acid ◽  
Biosynthetic Precursor

Synthesis of an analog of biosynthetic precursor Ia of lipid A by an improved method: a novel antagonist containing four (S)-3-hydroxy fatty acids

1995 ◽  
Vol 36 (41) ◽  
pp. 7455-7458 ◽  
Author(s):  
Koichi Fukase ◽  
Wen-Chi Liu ◽  
Yasuo Suda ◽  
Masato Oikawa ◽  
Akira Wada ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Lipid A ◽  
Hydroxy Fatty Acids ◽  
Improved Method ◽  
Biosynthetic Precursor

Parguerenes Revisited: New Brominated Diterpenes From the Southern Australian Marine Red Alga Laurencia Filiformis

1996 ◽  
Vol 49 (1) ◽  
pp. 19 ◽  
Author(s):  
SJ Rochfort ◽  
RJ Capon
Keyword(s):  
Natural Product ◽  
Biosynthetic Pathway ◽  
Spectroscopic Analysis ◽  
Red Alga ◽  
Biosynthetic Precursor ◽  
Chemical Correlation ◽  
New Compounds

Five new pargueranes, 15-bromoparguer-9(11)-ene-2,7,16,19-tetrol 2,7,16-triacetate (20), 15-bromoparguer-9(11)-ene-2,7,16-triol 2,7-diacetate (21), 15-bromoparguer-9(11)-ene-2,16-diol 2-acetate (22), 15-bromoparguer-9(11)-en-16-ol (23) and 15-bromoisoparguer-9(11)-en-16-ol (24), together with a plausible biosynthetic precursor, preparguerene (25), two known parguerenes , 15-bromoparguer-9(11)-ene-2,7,16,19-tetrol tetraacetate (4) and 15-bromoparguer-9(11)-ene-2,7,16-triol 2,16 diacetate (7), and the known algal metabolites (-)- aromadendrene (17), austradiol acetate (18) and austradiol diacetate (19), have been isolated from a collection of the southern Australian marine red alga Laurencia filiformis. The known synthetic parguerane 15-bromoparguer-9(11)-ene-2,7-16-triol triacetate (5) was also found for thefirst time as a natural product. In addition to securing the structures of new compounds by chemical correlation and detailed spectroscopic analysis, a lausible biosynthetic pathway has been proposed linking preparguerene, parguerene, isoparguerene and secoparguerene carbon skeletons.

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