scholarly journals Total Synthesis of the Natural Chalcone Lophirone E, Synthetic Studies toward Benzofuran and Indole-Based Analogues, and Investigation of Anti-Leishmanial Activity

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 463
Author(s):  
Luca Pozzetti ◽  
Roberta Ibba ◽  
Sara Rossi ◽  
Orazio Taglialatela-Scafati ◽  
Donatella Taramelli ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Leishmania Infantum ◽  
Anticancer Properties ◽  
Synthetic Strategy ◽  
Pathological Conditions ◽  
Structure Activity ◽  
Small Set ◽  
Synthetic Approaches ◽  
Therapeutic Leads

The potential of natural and synthetic chalcones as therapeutic leads against different pathological conditions has been investigated for several years, and this class of compounds emerged as a privileged chemotype due to its interesting anti-inflammatory, antimicrobial, antiviral, and anticancer properties. The objective of our study was to contribute to the investigation of this class of natural products as anti-leishmanial agents. We aimed at investigating the structure–activity relationships of the natural chalcone lophirone E, characterized by the presence of benzofuran B-ring, and analogues on anti-leishmania activity. Here we describe an effective synthetic strategy for the preparation of the natural chalcone lophirone E and its application to the synthesis of a small set of chalcones bearing different substitution patterns at both the A and heterocyclic B rings. The resulting compounds were investigated for their activity against Leishmania infantum promastigotes disclosing derivatives 1 and 28a,b as those endowed with the most interesting activities (IC50 = 15.3, 27.2, 15.9 μM, respectively). The synthetic approaches here described and the early SAR investigations highlighted the potential of this class of compounds as antiparasitic hits, making this study worthy of further investigation.

scholarly journals Synthesis of Highly Functionalised Furo[3,4-b]pyrans: Towards the Fungal Metabolite (−)-TAN-2483B

2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Ethyl Esters ◽  
Pyran Ring ◽  
Synthetic Strategy ◽  
Alternative Approach ◽  
Synthetic Approaches

<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>

scholarly journals Synthesis of Highly Functionalised Furo[3,4-b]pyrans: Towards the Fungal Metabolite (−)-TAN-2483B

2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Ethyl Esters ◽  
Pyran Ring ◽  
Synthetic Strategy ◽  
Alternative Approach ◽  
Synthetic Approaches

<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>

scholarly journals Development of a Divergent Route to Erythrina Alkaloids

Synlett ◽  
2020 ◽  
Vol 31 (04) ◽  
pp. 327-333 ◽  
Author(s):  
Jesper L. Kristensen ◽  
Sebastian Clementson ◽  
Mikkel Jessing ◽  
Paulo J. Vital
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
19Th Century ◽  
First Generation ◽  
Second Generation ◽  
Enantioselective Synthesis ◽  
Third Generation ◽  
Synthetic Strategy ◽  
Erythrina Alkaloids ◽  
The 19Th Century

Erythrina alkaloids were identified at the end of the 19th century and today, more than 100 members of the erythrinane family have been isolated. They are characterized by a unique tetracyclic, α-tertiary spiroamine scaffold. Herein we detail our efforts towards the development of a divergent enantioselective synthesis of (+)-dihydro-β-erythroidine (DHβE) – one of the most prominent members of this intriguing family of natural products.1 Introduction2 Synthetic Strategy2.1 First Generation2.2 Second Generation2.3 Third Generation2.3.1 Radical Endgame2.3.2 Completion of the Total Synthesis3 Conclusion

scholarly journals Synthetic Approaches to Tetracyclic Pyrrole Imidazole Marine Alkaloids

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Takuya Imaoka ◽  
Makoto Iwata ◽  
Takafumi Akimoto ◽  
Kazuo Nagasawa
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Anticancer Activity ◽  
Biological Activities ◽  
Structural Complexity ◽  
Marine Alkaloids ◽  
Ring Systems ◽  
Agonistic Activity ◽  
Synthetic Approaches

Oroidin derived pyrrole imidazole marine alkaloids (PIAs) are attractive targets for synthetic organic chemists because of their structural complexity and diversity as well as their interesting biological activities. A number of efforts have been carried out to develop strategies for the synthesis of these natural products. Members of PIAs ( eg., 2-7) which contain tetracyclic ring systems possessing characteristic cyclic guanidine or urea moieties show significant biological activities including anticancer activity and agonistic activity against the adrenoceptor. In this review investigations of the total synthesis of the representative tetracyclic PIAs dibromophakellin (2) and dibromophakellstatin (3) are described.

scholarly journals Concise and Gram-Scale Total Synthesis of Lansiumamides A and B and Alatamide

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3764
Author(s):  
Ran Lin ◽  
Xi Lin ◽  
Qian Su ◽  
Binbin Guo ◽  
Yanqin Huang ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Synthetic Strategy

The total synthesis of potent anti-obesity lansiumamide B was accomplished in four steps using commercially available materials. The synthetic strategy, featured with copper-catalyzed Buchwald coupling, is concise, convergent, practical and can be carried out on a one-gram scale. This approach could give either Z- or E-configured enamide moiety in natural products with absolute stereocontrol and was applied in the total synthesis of natural products.

Synthetic approaches to [5,6]-benzannulated spiroketal natural products

2011 ◽  
Vol 84 (6) ◽  
pp. 1379-1390 ◽  
Author(s):  
Michael C. McLeod ◽  
Margaret A. Brimble ◽  
Dominea C. K. Rathwell ◽  
Zoe E. Wilson ◽  
Tsz-Ying Yuen
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Electronic Properties ◽  
Late Stage ◽  
Biologically Active ◽  
Formal Synthesis ◽  
Berkelic Acid ◽  
Synthetic Approaches

Studies toward the synthesis of three biologically active [5,6]-benzannulated spiroketal natural products are described. The first total synthesis of paecilospirone is reported, employing a late-stage, pH-neutral spiroketalization. A formal synthesis of γ-rubromycin is described, where the spiroketal moiety is formed by delicate manipulation of the electronic properties of the spirocyclization precursor. Finally, model work toward the total synthesis of berkelic acid is summarized, introducing a novel Horner–Wadsworth–Emmons/oxa-Michael (HWE/oxa-M) cascade to access the spiroketal precursor.

scholarly journals The Synthesis of Aigialomycin D Analogues

2021 ◽  
Author(s):  
◽  
Samuel Z.Y. Ting
Keyword(s):  
Total Synthesis ◽  
Functional Group ◽  
Biological Activities ◽  
Biological Testing ◽  
Hsp90 Inhibition ◽  
Vast Array ◽  
Synthetic Strategy ◽  
Structure Activity ◽  
Expansive Group ◽  
Resorcylic Acid Lactones

<p>Aigialomycin D is a fungal natural product possessing kinase inhibition properties. It is a member of a class of compounds known as the resorcylic acid lactones, a expansive group containing compounds exhibiting a vast array of biological activities. These include kinase and Hsp90 inhibition, highly desirable properties in the drug development field. This research project sought to capitalise on previous work involving the successful total synthesis of aigialomycin D. By developing the synthetic methodology, analogues of aigialomycin D could be prepared for biological testing to obtain valuable structure-activity relationship information. The focus of this thesis involves the successful synthesis of aigialomycin D diastereomer, 5',6'-epi,epi-aigialomycin D and the attempted synthesis of 100-epi-aigialomycin D, via the synthetic strategy developed previously in combination with enantiomeric starting material fragments ... The synthesis of functional group analogues, 6'-oxo-aigialomycin D, 7',8'-cyclopropyl aigialomycin D and 5-chloro-agialomycin D were also attempted via derivatisation of late-stage intermediates in the aigialomycin D synthesis. The thesis herein recounts the successes and failures in the synthesis of various aigialomycin D analogues ...</p>

scholarly journals Total Synthesis and Biological Evaluation of Phaeosphaerides

Catalysts ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 206 ◽  
Author(s):  
Kenichi Kobayashi ◽  
Kosaku Tanaka ◽  
Hiroshi Kogen
Keyword(s):  
Crystal Structure ◽  
Natural Products ◽  
Total Synthesis ◽  
Structure Analysis ◽  
Endophytic Fungus ◽  
Biological Evaluation ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Structure Activity ◽  
Synthesis And Biological Evaluation

This article reviews studies regarding the total synthesis of phaeosphaerides A and B, nitrogen-containing bicyclic natural products isolated from an endophytic fungus. Numerous synthetic efforts and an X-ray crystal structure analysis of phaeosphaeride A have enabled revision of its originally proposed structure. In addition, a successful protic acid-mediated transformation of phaeosphaeride A to phaeosphaeride B revealed the hypothetical biosynthesis of phaeosphaeride B from phaeosphaeride A. Structure–activity relationship studies of phaeosphaeride derivatives are also discussed.

scholarly journals Aminomethylation/hydrogenolysis as an alternative to direct methylation of metalated isoquinolines – a novel total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline

2018 ◽  
Vol 14 ◽  
pp. 130-134 ◽  
Author(s):  
Benedikt C Melzer ◽  
Jan G Felber ◽  
Franz Bracher
Keyword(s):  
Natural Products ◽  
Drug Development ◽  
Total Synthesis ◽  
Benzyl Ether ◽  
Methyl Group ◽  
Novel Method ◽  
Synthetic Approaches

Highly-substituted isoquinolines are important scaffolds in syntheses of natural products and in drug development and hence, effective synthetic approaches are required. Here we present a novel method for the introduction of a methyl group at C1 of isoquinolines. This is exemplified by a new total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline. Direct metalation of 7-benzyloxy-6-methoxyisoquinoline with Knochel–Hauser base, followed by cuprate-mediated methylation gives the target alkaloid directly, but separation from the educt is cumbersome. Quenching the metalated intermediate with Eschenmoser’s reagent gives an easy to clean tertiary benzylamine, which, after quaternization with iodomethane, is easily converted into the desired 1-methylisoquinoline by hydrogenolysis of both the benzylamine and benzyl ether groups.

The intramolecular Diels–Alder reaction: recent advances and synthetic applications

1984 ◽  
Vol 62 (2) ◽  
pp. 183-234 ◽  
Author(s):  
Alex G. Fallis
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Synthetic Strategy ◽  
Diels Alder Reaction ◽  
Recent Advances ◽  
Cyclic Dienes

Recent advances and examples of the intramolecular Diels–Alder reaction are summarized and applications to the total synthesis of natural products, both completed and in progress, noted. A detailed discussion of trienes leading to bicyclo[4.3.0]nonene skeletons is followed by examples of bicyclo[4.4.0]decenes and adducts arising from ortho-quinodimethane precursors. Cycloadditions affording bicyclo[n.4.0] systems and bridged-ring adducts from cyclic dienes conclude this survey which is followed by a discussion of unreactive trienes and a brief analysis of synthetic strategy to complete the review.

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