Total synthesis of (–)-pateamine A, a novel immunosuppressive agent from Mycale sp

2004 ◽  
Vol 82 (2) ◽  
pp. 353-365 ◽  
Author(s):  
Gerald Pattenden ◽  
Douglas J Critcher ◽  
Modesto Remuiñán
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Sponge ◽  
Coupling Reaction ◽  
Immunosuppressive Agent ◽  
Side Chain ◽  
Amino Ester ◽  
Stille Reaction ◽  
Amino Esters ◽  
Pateamine A

A convergent synthesis of the unique thiazole-containing polyene bis-lactone pateamine A (1) isolated from the marine sponge Mycale sp is described. The synthesis features the ubiquitous Stille sp2–sp2 coupling reaction to elaborate the E,Z-diene macrolide core 23 and the all-E polyenamine side chain in the natural product. It also highlights the scope for enantiopure sulfinimine intermediates in the synthesis of chiral β-amino ester moieties in complex structures.Key words: pateamine A, immunosuppressive agent from marine sponge Mycale sp, total synthesis, novel 19-membered bis-lactone, thiazole metabolite, polyenamine, Stille reaction, sulfinimines, chiral β-amino esters.

Synthesis of Dichotomin A: Use of a Penicillamine-Derived Pseudoproline to Furnish Native Valine Residues

2015 ◽  
Vol 68 (4) ◽  
pp. 627 ◽  
Author(s):  
Michelle S. Y. Wong ◽  
Deni Taleski ◽  
Katrina A. Jolliffe
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
Linear Peptide ◽  
Cyclic Hexapeptide ◽  
Peptide Precursors ◽  
Head To Tail Cyclization

The total synthesis of cyclic hexapeptide dichotomin A from linear peptide precursors containing penicillamine-derived pseudoproline residues is reported. The incorporation of a pseudoproline residue led to a faster reaction and higher head-to-tail cyclization yields in comparison to linear precursors containing the native valine residue. However, deprotection of the pseudoproline resulted in significant amounts of a by-product in which a threonine side chain had undergone dehydration, resulting in a low overall yield of the natural product.

scholarly journals Regioselective side-chain amination of 2-alkyl azacycles by radical translocation: total synthesis of tetraponerine T8

2021 ◽  
Author(s):  
Samuel D. Griggs ◽  
Alejandro Martin-Roncero ◽  
Adam Nelson ◽  
Stephen P. Marsden
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain

Radical translocation facilitates the regioselective γ-amination of 2-alkyl-substituted azacycles, leading to 1,3-diamines including the alkaloidal natural product tetraponerine T8.

Convergent First Total Synthesis of Melovinone: A Densely Substituted 3-Methoxy-4-quinolone Isolated from Melochia tomentosa L.

Synthesis ◽  
2019 ◽  
Vol 51 (22) ◽  
pp. 4253-4262
Author(s):  
Abel A. Arroyo Aguilar ◽  
Gabriela N. Ledesma ◽  
Bárbara Tirloni ◽  
Teodoro S. Kaufman ◽  
Enrique L. Larghi
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Nitro Group ◽  
Nmr Spectra ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Full Agreement ◽  
Nitrobenzoic Acid ◽  
Microwave Assisted ◽  
Cross Coupling Reaction

The first total synthesis of melovinone, a nonrutaceous 3-methoxy-4-quinolone alkaloid isolated from Melochia tomentosa L., is reported. The target was acquired in a convergent fashion through the Suzuki–Miyaura cross-coupling reaction between an ortho-nitrobenzoic acid acetonyl ester derivative prepared from vanillin and potassium 5-phenyl-1-pentyltrifluoroborate, obtained from β-phenethyl bromide. The coupling was followed by a chemoselective reduction of the nitro group and a microwave-assisted and AcOH-promoted cyclization with rearrangement of the resulting acetonyl anthranilate. This afforded a pseudane intermediate, which was selectively methylated on the 3-OH. The synthetic pathway enabled to reach the objective in 11 steps and 18% overall yield. The 1H NMR spectra of the synthetic and natural product were in full agreement.

scholarly journals Total Synthesis of 4-Acetyl-1,3-Dihydroimidazo[4,5-c]Pyridin-2-One, a New Microbial Metabolite from a Streptomyces Species

2009 ◽  
Vol 4 (7) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Tobias Bender ◽  
Paultheo von Zezschwitz
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Secondary Metabolite ◽  
Pyridine Derivative ◽  
Stille Reaction ◽  
Streptomyces Species ◽  
Streptomyces Sp ◽  
Microbial Metabolite

The structure of a new secondary metabolite from Streptomyces sp. was determined as 4-acetyl-1,3-dihydroimidazo[4,5-c]pyridin-2-one by synthesis of the natural product itself and of the regioisomeric 7-acetylimidazo[4,5-b]pyridine derivative. The former compound was prepared, in 28% overall yield, in a sequence of nitration, reduction, condensation, and Stille reaction of 4-aminopyridine, while the regioisomer was obtained in 5% overall yield by amination, nitration, reduction, condensation, and oxidation of 4-ethylpyridine.

scholarly journals Concise Large-Scale Synthesis of Tomatidine, A Potent Antibiotic Natural Product

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6008
Author(s):  
Chad Normandin ◽  
Pierre-Luc Boudreault
Keyword(s):  
Natural Product ◽  
Large Scale ◽  
Low Cost ◽  
Coupling Reaction ◽  
Flash Chromatography ◽  
Side Chain ◽  
Fields Of Study ◽  
Type Coupling ◽  
F Ring ◽  
Multiple Strains

Tomatidine has recently generated a lot of interest amongst the pharmacology, medicine, and biology fields of study, especially for its newfound activity as an antibiotic agent capable of targeting multiple strains of bacteria. In the light of its low natural abundance and high cost, an efficient and scalable multi-gram synthesis of tomatidine has been developed. This synthesis uses a Suzuki–Miyaura-type coupling reaction as a key step to graft an enantiopure F-ring side chain to the steroidal scaffold of the natural product, which was accessible from low-cost and commercially available diosgenin. A Lewis acid-mediated spiroketal opening followed by an azide substitution and reduction sequence is employed to generate the spiroaminoketal motif of the natural product. Overall, this synthesis produced 5.2 g in a single pass in 15 total steps and 15.2% yield using a methodology that is atom economical, scalable, and requires no flash chromatography purifications.

A Ruthenium-Catalyzed C–H Activation Strategy as an Efficient Shortcut in the Total Synthesis of 6,8-Dimethoxy-1,3-dimethyl­isoquinoline

Synthesis ◽  
2019 ◽  
Vol 51 (20) ◽  
pp. 3908-3914
Author(s):  
Santiago Fonzo ◽  
Didier F. Vargas ◽  
Teodoro S. Kaufman
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
One Pot ◽  
Microwave Assisted ◽  
Efficient Route ◽  
Carbon Side Chain

A short and convenient total synthesis of 6,8-dimethoxy-1,3-dimethylisoquinoline, employing a C–H activation/alkenylation strategy, is reported. The approach involves the CeCl3·7H2O-promoted methoximation of 2,4-dimethoxyacetophenone and a methoxime-directed ruthenium-catalyzed allylation. This was followed by a one-pot, ruthenium-catalyzed allyl to propenyl isomerization and a microwave-assisted 6π-azaelectrocylization to complete the sequence. This approach, which entails a shortcut in the synthetic management of the three-carbon side chain, is an improved and more efficient route toward the natural product, which facilitated its access in just three steps and 27.3% overall yield.

scholarly journals Recent Advances in the Total Synthesis of Tetramic Acid-Containing Natural Products

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Wen-Ju Bai ◽  
Chen Lu ◽  
Xiqing Wang
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
Tetramic Acid ◽  
Unique Type ◽  
Recent Advances ◽  
Chemistry Community

With incredible bioactivities and fascinating structural complexities, tetramic acid- (TA-) containing natural products have attracted favorable attention among the organic chemistry community. Although the construction of the TA core is usually straightforward, the intricate C3-side chain sometimes asks for some deliberative strategy so as to fulfill an elegant total synthesis. This review mainly covers some exceptional synthetic examples for each type of natural product in recent years, showcasing the great achievements as well as unsettled obstacles in this area, in the hope of accelerating the synthetic and biological investigations for this unique type of natural product.

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