Synthesis of the fatty acid of pramanicin

1997 ◽  
Vol 75 (6) ◽  
pp. 884-889 ◽  
Author(s):  
Christopher Cow ◽  
David Valentini ◽  
Paul Harrison

The natural product tetradec-2-enoic acid-4,5-epoxide (2), which is also a component of the antibiotic pramanicin (1), was prepared in racemic form by a glycoluril-template directed approach. Two sequential additions of acetate units to decanoic acid are effected by intramolecular condensations on the template, mimicking the proposed biosynthetic pathway to 1. Cleavage of the grown trans,trans-tetradeca-2,4-dienoyl chain from the template and epoxidation yields 2. The reaction sequence illustrates the applicability of this biomimetic approach to total synthesis of natural products. Keywords: pramanicin, biomimetic, glycoluril, template.

mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Daniela B. B. Trivella ◽  
Rafael de Felicio

ABSTRACT Natural products are the richest source of chemical compounds for drug discovery. Particularly, bacterial secondary metabolites are in the spotlight due to advances in genome sequencing and mining, as well as for the potential of biosynthetic pathway manipulation to awake silent (cryptic) gene clusters under laboratory cultivation. Further progress in compound detection, such as the development of the tandem mass spectrometry (MS/MS) molecular networking approach, has contributed to the discovery of novel bacterial natural products. The latter can be applied directly to bacterial crude extracts for identifying and dereplicating known compounds, therefore assisting the prioritization of extracts containing novel natural products, for example. In our opinion, these three approaches—genome mining, silent pathway induction, and MS-based molecular networking—compose the tripod for modern bacterial natural product discovery and will be discussed in this perspective.


2014 ◽  
Vol 10 ◽  
pp. 1228-1232 ◽  
Author(s):  
Jens Schmidt ◽  
Zeinab Khalil ◽  
Robert J Capon ◽  
Christian B W Stark

The heronapyrroles A–C have first been isolated from a marine-derived Streptomyces sp. (CMB-0423) in 2010. Structurally, these natural products feature an unusual nitropyrrole system to which a partially oxidized farnesyl chain is attached. The varying degree of oxidation of the sesquiterpenyl subunit in heronapyrroles A–C provoked the hypothesis that there might exist other hitherto unidentified metabolites. On biosynthetic grounds a mono-tetrahydrofuran-diol named heronapyrrole D appeared a possible candidate. We here describe a short asymmetric synthesis of heronapyrrole D, its detection in cultivations of CMB-0423 and finally the evaluation of its antibacterial activity. We thus demonstrate that biosynthetic considerations and the joint effort of synthetic and natural product chemists can result in the identification of new members of a rare class of natural products.


2020 ◽  
Author(s):  
Justin Shapiro ◽  
Savannah Post ◽  
William Wuest

In a 2016 screen of natural product extracts a new family of natural products, the cahuitamycins, was discovered and found to inhibit the formation of biofilms in the human pathogen <i>Acinetobacter baumannii</i>. The molecules contain an unusual piperazate residue that raises structure/function and biosynthesis questions and resemble iron-trafficking virulence factors from <i>A. baumannii</i>, suggesting a connection between metal homeostasis and biofilm-mediated pathogenicity. Here we disclose the first total synthesis of the reported structure of cahuitamycin A in a twelve-step longest linear sequence and 18% overall yield. Comparison of spectral data of the authentic natural product and synthetic target compound demonstrate that the reported structure is distinct from the isolated metabolite. Herein, we propose an alternative structure to reconcile our findings with the isolation report, setting the stage for future synthetic and biochemical investigations of an important class of natural products.


2000 ◽  
Vol 72 (9) ◽  
pp. 1783-1786 ◽  
Author(s):  
Keisuke Suzuki

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.


2020 ◽  
Vol 37 (8) ◽  
pp. 1065-1079 ◽  
Author(s):  
Christian R. Zwick ◽  
Hans Renata

This review highlights recent chemoenzymatic syntheses of natural products that feature strategic applications of oxidative transformations with Fe/αKG enzymes.


2019 ◽  
Vol 17 (31) ◽  
pp. 7270-7292 ◽  
Author(s):  
Sagar S. Thorat ◽  
Ravindar Kontham

Oxaspirolactones are ubiquitous structural motifs found in natural products and synthetic molecules with a diverse biochemical and physicochemical profile, and represent a valuable target in natural product chemistry and medicinal chemistry.


Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4147 ◽  
Author(s):  
Jens M. J. Nolsøe ◽  
Marius Aursnes ◽  
Yngve H. Stenstrøm ◽  
Trond V. Hansen

Recently, the identity of the marine hydrindane natural product (−)-mucosin was revised to the trans-fused structure 6, thereby providing a biogenetic puzzle that remains to be solved. We are now disseminating some of our insights with regard to the possible machinery delivering the established architecture. Aspects with regard to various modes of cyclization in terms of concerted versus stepwise processes are held up against the enzymatic apparatus known to be working on arachidonic acid (8). To provide a contrast to the tentative polyunsaturated fatty acid biogenesis, the structural pattern featured in (−)-mucosin (6) is compared to some marine hydrinane natural products of professed polyketide descent. Our appraisal points to a different origin and strengthens the hypothesis of a polyunsaturated fatty acids (PUFA) as the progenitor of (−)-mucosin (6).


2018 ◽  
Vol 5 (1) ◽  
pp. 132-150 ◽  
Author(s):  
Pengquan Chen ◽  
Yuecheng Wu ◽  
Shifa Zhu ◽  
Huanfeng Jiang ◽  
Zhiqiang Ma

This review highlights the recent applications of Ir-catalyzed reactions in the total synthesis of natural products.


2019 ◽  
Author(s):  
Cedric Hugelshofer ◽  
Vignesh Palani ◽  
Richmond Sarpong

The first total synthesis of the complex hexacylic Daphniphyllum alkaloid (–)-daphlongamine H in enantioenriched form has been accomplished. Key to the success of the strategy are a complexity-building Mannich reaction, efficient cyclizations, and a highly diastereoselective hydrogenation to assemble multigram quantities of the tricyclic core bearing four contiguous stereocenters. Following construction of the hydro-indene substructure by means of a Pauson–Khand reaction, endgame redox manipulations delivered the natural product. Importantly, the synthetic studies have also given access to (–)-isodaphlongamine H and led to a revision of the reported structure of deoxyisocalyciphylline B, which resulted in the proposal of a modified biosynthetic pathway to the calyciphylline B-type alkaloids.


2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne

<p>Carbohydrate-derived cyclopropanes combine both the stereochemical wealth of carbohydrates and the reactivity of cyclopropanes. A diverse variety of reaction modes for these cyclopropyl carbohydrates can be harnessed for the synthesis of natural products and other targets.  The natural products (−)-TAN-2483A and (−)-TAN-2483B are fungal secondary metabolites displaying a variety of bioactivities such as inhibition of c-src kinase action and parathyroid hormone-induced bone resorption. This thesis described several synthetic approaches to the natural product (−)-TAN-2483B and analogues of (−)-TAN-2483B employing cyclopropane ring expansion.  The synthetic route to (−)-TAN-2483B began with the readily available substrate D-mannose. The pyran ring unsaturation of the natural product was established by a cyclopropanation-ring expansion sequence. A synthetic strategy via dichlorocyclopropane-based intermediates is described in chapter 2. This being unsuccessful, an alternative approach via 2-fomyl-glycal was developed in chapter 3. The chapter 2 and 3 provided a solid background for the achievement of the analogues synthesis illustrated in chapter 4 via dibromocyclopropane. Lewis acid-mediated alkynylation followed by Pdcatalysed carbonylative lactonisation was successfully utilised in the revelation of the furo[3,4-b]pyran ring skeleton. This route afforded analogues of TAN-2483B; the Z-and E-unsaturated ethyl esters 140 and 141 and hydroxy(−)-TAN-2483B 145. The total synthesis of (−)-TAN-2483B was not achieved due to unforeseen obstacles encountered in the deoxygenation of the side arm of 335 (Chapter 4) into the E-propenyl side arm of (−)-TAN-2483B.</p>


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