Talaronoids A–D: four fusicoccane diterpenoids with an unprecedented tricyclic 5/8/6 ring system from the fungus Talaromyces stipitatus

2020 ◽  
Vol 7 (21) ◽  
pp. 3486-3492
Author(s):  
Mi Zhang ◽  
Shan Yan ◽  
Yu Liang ◽  
Meijia Zheng ◽  
Zhaodi Wu ◽  
...  
Keyword(s):  
Natural Products ◽  
Ring System ◽  
Carbon Skeleton

Talaronoids A–D (1–4), four fusicoccane diterpenoids with an unexpected tricyclic 5/8/6 carbon skeleton from Talaromyces stipitatus, represent the first examples of natural products with a benzo[a]cyclopenta[d]cyclooctane skeleton.

Synthesis of Spongidine A, D and Petrosaspongiolide L Methyl Ester Using Pyridine C-H Functionalization

2019 ◽  
Author(s):  
Florian Bartels ◽  
Manuela Weber ◽  
Mathias Christmann
Keyword(s):  
Natural Products ◽  
Methyl Ester ◽  
Hydrogen Atom ◽  
Phospholipase A2 ◽  
Late Stage ◽  
Hydrogen Atom Transfer ◽  
Ring System ◽  
Tetracyclic Core ◽  
Intramolecular Hydrogen ◽  
Phospholipase A2 Inhibitors

<div>An efficient strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer‐initiated Minisci reaction. A divergent late‐stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methyl ester.</div>

Eremophilane-type sesquiterpenes from fungi and their medicinal potential

2017 ◽  
Vol 399 (1) ◽  
pp. 13-28 ◽  
Author(s):  
Kamila Tomoko Yuyama ◽  
Diana Fortkamp ◽  
Wolf-Rainer Abraham
Keyword(s):  
Fatty Acids ◽  
Natural Products ◽  
Carbon Skeleton ◽  
New Drugs ◽  
Special Focus ◽  
Bioactive Natural Products ◽  
Pharmacokinetic Assessment ◽  
Immunomodulatory Properties ◽  
Chemical Tools ◽  
Subsequent Improvement

AbstractEremophilanes are sesquiterpenes with a rearranged carbon skeleton formed both by plants and fungi, however, almost no plant eremophilanes are found in fungi. These eremophilanes possess mainly phytotoxic, antimicrobial, anticancer and immunomodulatory properties and in this review fungal eremophilanes with bioactivities of potential medicinal applications are reviewed and discussed. A special focus is set on natural products bearing highly functionalized fatty acids at C-1 or C-3 position of the eremophilane backbone. Many of these fatty acids seem to contribute to the bioactivity of the metabolites enhancing the activity of the sesquiterpene moieties. Several approaches for optimization of these natural products for clinical needs and testing of the resulting derivatives are presented and discussed. The combination of identification of bioactive natural products with their subsequent improvement using a variety of genetical or chemical tools and the pharmacokinetic assessment of the products is presented here as a promising approach to new drugs.

Activated cycloheptenone dienophiles. A versatile approach to 6,7-fused ring targets

1995 ◽  
Vol 73 (7) ◽  
pp. 1135-1147 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Wen-Lung Yeh ◽  
Eric N.C. Browne
Keyword(s):  
Natural Products ◽  
Alder Reaction ◽  
Ring System ◽  
Membered Ring ◽  
Diels Alder ◽  
Substitution Pattern ◽  
Diels Alder Reaction ◽  
Fused Ring ◽  
Fused Ring System

Several 2-carbalkoxy-2-cyclohepten-1-ones were prepared and their Diels–Alder characteristics examined in order to develop a facile general approach to the synthesis of cycloheptane ring-containing polycyclic natural products. Substitution pattern on the seven-membered ring was found to greatly affect the Diels–Alder behavior. In addition, some extraordinary facial stereoselectivity was observed. Keywords: Diels–Alder reaction, 2-carbalkoxy-2-cyclohepten-1-ones, 6,7-fused ring system.

Tryptophan oxygenation: mechanistic considerations

2012 ◽  
Vol 40 (3) ◽  
pp. 509-514 ◽  
Author(s):  
James H. Naismith
Keyword(s):  
Natural Products ◽  
Amino Acid ◽  
Molecular Oxygen ◽  
Ring System ◽  
Hydrophobic Core ◽  
Indole Ring ◽  
Multiple Strategies ◽  
Tryptophan Dioxygenase ◽  
Recent Developments ◽  
Hydrophobic Anchor

From a protein structural viewpoint, tryptophan is often considered an inert structural amino acid, playing a role as a hydrophobic anchor in membrane proteins or as part of the hydrophobic core of soluble proteins. However, tryptophan is the only polyaromatic amino acid and, from a chemical viewpoint, possesses unique reactivity owing to the electron-richness of the indole system. This reactivity is seen in the area of natural products and metabolites which have exquisite modifications of the indole ring system. Enzymes have evolved multiple strategies to break or modify the indole ring; one particular class is the IDO/TDO (indoleamine/tryptophan dioxygenase) superfamily. A new member of this family, PrnB, on the surface catalyses a very different reaction, but actually shares much of the early chemistry with the tryptophan dioxygenases. Studies on PrnB have contributed to our understanding of the wider superfamily. In the present mini-review, recent developments in our understanding of how the TDO class of enzymes use activated molecular oxygen to break the indole ring are discussed.

The structure determination of two related eremophilone dimers

1982 ◽  
Vol 35 (4) ◽  
pp. 809 ◽  
Author(s):  
DE Lewis ◽  
RA Massy-Westropp ◽  
CF Ingham ◽  
RJ Wells
Keyword(s):  
Natural Products ◽  
Structure Determination ◽  
Carbon Skeleton ◽  
X Ray ◽  
New Class

The first representatives of a new class of eremophilone dimers have been isolated from the wood oil of Eremophila mitchelli and shown by a combination of spectroscopic and X-ray techniques to possess the unusual 1-(8',8'a-dimethylperhydronaphthalen-2'-yl)-1,4,5,10a-tetramethylperhydroanthracene carbon skeleton. These two natural products are the first C30 compounds to be isolated from any member of the genus Eremophila.

The Chemistry of Laurenene. X. A New Carbon Skeleton by Rearrangement of Laurenan-2-β-ol

1990 ◽  
Vol 43 (1) ◽  
pp. 141 ◽  
Author(s):  
PJ Eaton ◽  
AR Hayman ◽  
RT Weavers
Keyword(s):  
Trifluoroacetic Acid ◽  
Major Product ◽  
Ring System ◽  
Membered Ring ◽  
Carbon Skeleton ◽  
Deuterium Labelling ◽  
Carbon Ring ◽  
Starting Point ◽  
Remote Part

Treatment of laurenan-2β-ol (2) with trifluoroacetic acid in dichloromethane at 0° gives as the major product the rearranged alkene (4). This compound has a new carbon-ring system containing three five-membered rings and one six- membered ring. The structure of (4) has been determined by a range of n.m.r. techniques applied to (4) and selected derivatives. Deuterium- labelling experiments have established that the rearrangement proceeds to a remote part of the molecule and then returns to its starting point.

The Chemistry of Eremophila spp. XXII. New Eremane Diterpenes from E. fraseri

1985 ◽  
Vol 38 (9) ◽  
pp. 1351 ◽  
Author(s):  
PJ Carroll ◽  
LM Engelhardt ◽  
L Ghisalberti ◽  
PR Jefferies ◽  
EJ Middleton ◽  
...  
Keyword(s):  
Ring System ◽  
Carbon Skeleton ◽  
X Ray ◽  
Diterpene Acids

The resin components of different collections of the highly variable Eremophila fraseri F. Muell. Have been examined. Five new eremane diterpene acids have been characterized and evidence for their structures is presented. The structure of a new diterpene, also isolated from E. fraseri, has been determined by X-ray crystallographic methods. The carbon skeleton of this new diterpene incorporates a tricyclo[6.2.1.01,5]undecane ring system.

scholarly journals A REVIEW OF BENZOPYRAN DERIVATIVES IN PHARMACOTHERAPY OF BREAST CANCER

2018 ◽  
Vol 11 (7) ◽  
pp. 43 ◽  
Author(s):  
Kumar Piyush ◽  
Singh Kuldeep ◽  
Rahman Md. Azizur ◽  
Hasan Syed Misbahul ◽  
Wal Pranay
Keyword(s):  
Breast Cancer ◽  
Natural Products ◽  
Biological Effects ◽  
Mechanisms Of Action ◽  
Ring System ◽  
Pharmacological Properties ◽  
Substitution Pattern ◽  
Naturally Occurring ◽  
Anti Hiv ◽  
Cancer Activity

One of the naturally occurring compounds containing oxygen moiety is benzopyran. Depending on its substitution pattern, different biological effects are shown. The benzopyran ring system is present in many natural products (such as genistein, hesperidin, and warfarin) as well as synthetic products. It displays pharmacological properties such as antitumor, anti-HIV, antimicrobials, anti-inflammatory, and anticoagulants. The sufficient literature support and the fact that benzopyran has potential as a pharmacophore particularly as anti-breast cancer, etc, current research seemed pertinent keeping in view the mechanism of anti-breast cancer activity. Therefore, the objective of this review is to focus on important benzopyran analogs with anti-breast cancer activity and highlight their mechanisms of action.

scholarly journals A Review of Fungal Protoilludane Sesquiterpenoid Natural Products

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 928
Author(s):  
Melissa M. Cadelis ◽  
Brent R. Copp ◽  
Siouxsie Wiles
Keyword(s):  
Natural Products ◽  
Drug Discovery ◽  
Structure Elucidation ◽  
Structural Diversity ◽  
Ring System ◽  
Diverse Range ◽  
Total Syntheses ◽  
Chemical Structures ◽  
Drug Leads ◽  
Unique Chemical

Natural products have been a great source for drug leads, due to a vast majority possessing unique chemical structures. Such an example is the protoilludane class of natural products which contain an annulated 5/6/4-ring system and are almost exclusively produced by fungi. They have been reported to possess a diverse range of bioactivities, including antimicrobial, antifungal and cytotoxic properties. In this review, we discuss the isolation, structure elucidation and any reported bioactivities of this compound class, including establishment of stereochemistry and any total syntheses of these natural products. A total of 180 protoilludane natural products, isolated in the last 70 years, from fungi, plant and marine sources are covered, highlighting their structural diversity and potential in drug discovery.

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