scholarly journals Synthesis and structure revision of symplocin A

2017 ◽  
Vol 4 (6) ◽  
pp. 995-1004 ◽  
Author(s):  
Lu-Ping Shao ◽  
Chang-Mei Si ◽  
Zhuo-Ya Mao ◽  
Wen Zhou ◽  
Tadeusz F. Molinski ◽  
...  
Keyword(s):  
Natural Product ◽  
2D Nmr ◽  
One Pot ◽  
Linear Peptide ◽  
Structure Revision ◽  
First Time

Symplocin A, a linear peptide has been synthesized for the first time employing our previously established ‘one-pot intramolecular tandem protocol’. Moreover, the stereochemistry of natural symplocin A was unambiguously revised through the confirmation by 1D NMR, 2D NMR, and HPLC comparisons with an authentic natural product.

scholarly journals Antialactone: A New γ-Lactone from Antiaris Africana, and its Absolute Configuration Determined from TDDFT CD Calculations

2008 ◽  
Vol 3 (2) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Vouffo Bertin ◽  
Hidayat Hussain ◽  
Simeon F. Kouam ◽  
Etienne Dongo ◽  
Gennaro Pescitelli ◽  
...  
Keyword(s):  
Natural Product ◽  
Absolute Configuration ◽  
Betulinic Acid ◽  
Spectroscopic Data ◽  
Nmr Spectra ◽  
2D Nmr ◽  
Stem Bark ◽  
Cd Spectra ◽  
2D Nmr Spectra ◽  
First Time

Four compounds were isolated from the stem bark of Antiaris africana. One of them, a γ-lactone named antialactone (1a), is reported for the first time as a natural product. The structures were determined by comprehensive analyses of their 1D and 2D NMR spectra and EI MS data. The absolute configuration of antialactone acetate (1b) was established by TDDFT CD calculations and comparison with measured CD spectra. The remaining three known compounds were identified, by comparing their spectroscopic data with those reported in the literature, as lichenxanthone, β-sitosterol, and betulinic acid.

scholarly journals Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

2017 ◽  
Vol 13 ◽  
pp. 54-62 ◽  
Author(s):  
Andreas C Boukis ◽  
Baptiste Monney ◽  
Michael A R Meier
Keyword(s):  
Multicomponent Reactions ◽  
Biginelli Reaction ◽  
2D Nmr ◽  
Solvent System ◽  
Solvent Mixture ◽  
Tandem Reaction ◽  
Reaction Step ◽  
Passerini Reaction ◽  
One Pot ◽  
First Time

The Biginelli reaction was combined with the Passerini reaction for the first time in a sequential multicomponent tandem reaction approach. After evaluation of all possible linker components and a suitable solvent system, highly functionalized dihydropyrimidone–α-acyloxycarboxamide compounds were obtained in good to excellent yields. In a first reaction step, different 3,4-dihydropyrimidin-2(1H)-one acids were synthesized, isolated and fully characterized. These products were subsequently used in a Passerini reaction utilizing a dichloromethane/dimethyl sulfoxide solvent mixture. By variation of the components in both multicomponent reactions, a large number of structurally diverse compounds could be synthesized. In addition, a one-pot Biginelli–Passerini tandem reaction was demonstrated. All products were carefully characterized via 1D and 2D NMR as well as IR and HRMS.

Isolation, Structure Elucidation and Activity of Anthracycline Acetates from a Terrestrial Streptomyces sp.

2003 ◽  
Vol 58 (12) ◽  
pp. 1242-1246 ◽  
Author(s):  
Serge Fotso ◽  
Rajendra P. Maskey ◽  
Iris Grün-Wollny ◽  
Hartmut Laatsch
Keyword(s):  
Molecular Weight ◽  
Natural Product ◽  
Structure Elucidation ◽  
Ethyl Acetate Extract ◽  
2D Nmr ◽  
Streptomyces Sp ◽  
Naturally Occurring ◽  
Nmr Data ◽  
New Antibiotics ◽  
First Time

The red coloured ethyl acetate extract of the Streptomyces sp. isolate GW37/3236 delivered the two new antibiotics 13-O-acetyl-bisanhydro-13-dihydrodaunomycinone (3c) and 4,13-O-diacetylbisanhydro- 4-O-demethyl-13-dihydrodaunomycinone (3d) and additionally several known compounds. The quinones 3c and 3d are the first naturally occurring quinone acetates. Their structures were derived by comparison of the NMR data with those of bisanhydro-13-dihydrodaunomycinone (3b) and by interpretation of the 2D NMR data accompanied by the molecular weight and formula. 2-Acetamido-3-hydroxybenzamide (5) was also isolated from the extract and was identified by comparison of the NMR data with those of 2-acetamidobenzamide and by 2D NMR correlations. 6,9,11- Trihydroxy-4-methoxy-5,12-naphthacenedione (4) is isolated for the first time as a natural product.

scholarly journals New Anti-inflammatory Flavonol Glycosides from Lindera akoensis Hayata

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 563
Author(s):  
Chung-Ping Yang ◽  
Pei-Hsin Shie ◽  
Guan-Jhong Huang ◽  
Shih-Chang Chien ◽  
Yueh-Hsiung Kuo
Keyword(s):  
Traditional Medicine ◽  
Natural Product ◽  
2D Nmr ◽  
Flavonol Glycosides ◽  
Ic50 Value ◽  
Raw264.7 Cell ◽  
Anti Inflammatory ◽  
First Time ◽  
Three Components

Inflammation is related to many diseases. Lindera akoensis Hayata was often used in folktherapy in Taiwan for inflammation. In this study, three new flavonol acyl glycosides, namelykaempferol-3-O--D-4”,6”-di-(E)-p-coumaroylglucoside (1), 3”-(E)-p-coumaroylafzelin (2) and 40-Omethyl-2”,4”-di-(E)-p-coumaroylquercitrin (3), and three components, 3-dodecyl-4-hydroxy-5-methyldihydrofuran-2-one (4), 2-acetoxyclovan-9-ol (5), (1,4,6)-trihydroxyeudesmane(6) that were isolated from the natural product for the first time were obtained along with 25 knowncompounds from L. akoensis. Their structures were determined by comprehensive spectroscopicanalyses (1D and 2D NMR, EI-, ESI- and HRESI-MS). The ability of 1 to decrease the LPS-stimulatedproduction of nitrite in RAW264.7 cell was evaluated, showing an IC50 value of 36.3 ± 3.2 μM.This result supports the value of L. akoensis as a traditional medicine resource.

scholarly journals Two New Diterpene Phenols from Calocedrus decurrans

2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500
Author(s):  
Sheeba Veluthoor ◽  
Shujun Li ◽  
Rick G. Kelsey ◽  
Marc C. Dolan ◽  
Nicholas A. Panella ◽  
...  
Keyword(s):  
Natural Product ◽  
2D Nmr ◽  
Nmr Techniques ◽  
First Time ◽  
New System

Two new p-cymene based diphenols (1-2) were isolated from the heartwood of Calocedrus decurrans. Structures were elucidated by 1D and 2D NMR techniques and HRMS. Libocedroquinone (3) was also isolated as a natural product for the first time. A new system of nomenclature is proposed for description of such oligomeric p-cymene derivatives.

A One-Pot Chemoenzymatic Synthesis of (2S,4R)-4-Methylproline Enables the First Total Synthesis of Antiviral Lipopeptide Cavinafungin B

2018 ◽  
Author(s):  
Christian R. Zwick ◽  
Hans Renata
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Complex Molecule ◽  
Molecular Target ◽  
Chemoenzymatic Synthesis ◽  
General Strategy ◽  
One Pot

We report an efficient ten-step synthesis of antiviral natural product cavinafungin B in 37% overall yield. By leveraging a one-pot chemoenzymatic synthesis of (2S,4R)-4-methylproline and oxazolidine-tethered (Rink-Boc-ATG-resin) SPPS methodology, the assembly of our molecular target could be conducted in an efficient manner.This general strategy could prove amenable to the construction of other natural and unnatural linear lipopeptides. The value of incorporating biocatalytic steps in complex molecule synthesis is highlighted by this work.

Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation

2019 ◽  
Author(s):  
Miles Aukland ◽  
Mindaugas Šiaučiulis ◽  
Adam West ◽  
Gregory Perry ◽  
David Procter
Keyword(s):  
Natural Product ◽  
Selective Reduction ◽  
Cross Coupling ◽  
One Pot ◽  
Complex Molecules ◽  
Pummerer Reaction ◽  
Metal Free ◽  
Bond Forming ◽  
Coupling Partner ◽  
Bioactive Natural Product

<p>Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p>

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

scholarly journals Chemical Constituents of the Marine Sponge Aaptos aaptos (Schmidt, 1864) and Their Cytotoxic Activity

2021 ◽  
Vol 16 (2) ◽  
pp. 1934578X2199334
Author(s):  
Do Thi Trang ◽  
Bui Huu Tai ◽  
Dan Thuy Hang ◽  
Pham Hai Yen ◽  
Phan Thi Thanh Huong ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Spectral Data ◽  
Absolute Configuration ◽  
Marine Sponge ◽  
Chemical Constituents ◽  
2D Nmr ◽  
Extensive Analysis ◽  
First Time ◽  
Tddft Method ◽  
Mcf 7

Seven compounds (1-7) were isolated from the marine sponge Aaptos aaptos living in the Vietnamese sea. Their structures were determined as 2 hours, 5 H,7 H,9 H-9 S-hydroxy-imidazo[1,5- α]pyridine-1,3-dione (1), 3-([9-methylhexadecyl]oxy)propane-1,2-diol 2, 2,3-dihydro-2,3-dioxoaaptamine (3), indol-3-aldehyde (4), methyl indole-3-carboxylate (5) 4-hydroxy-5-(indole-3-yl)−5-oxo-pentan-2-one (6), and thymidine (7) by extensive analysis of HR-ESI-MS, 1D, and 2D NMR spectral data, as well as by comparison of the spectral data with those reported in the literature. In addition, the absolute configuration of 1 was determined from the experimental ECD spectrum and comparison of this with the theoretical ECD calculations using the TDDFT method. Compounds 1 and 2 were isolated from nature for the first time. Compound 3 induced cytotoxic activity against SK-LU-1, MCF-7, HepG2, and SK-Mel-2 cell lines with IC50 values of 41.27 ± 2.63, 40.70 ± 2.65, 34.31 ± 3.43, and 36.63 ± 1.40 µM, respectively.

Amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks as efficient catalysts for one-pot cascade reactions

2019 ◽  
Vol 43 (5) ◽  
pp. 2269-2273 ◽  
Author(s):  
Guojie Meng ◽  
Shengguang Gao ◽  
Ying Liu ◽  
Li Zhang ◽  
Chunmei Song ◽  
...  
Keyword(s):  
Cascade Reactions ◽  
One Pot ◽  
First Time

The synthesis of amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks for one-pot cascade reactions was reported for the first time.

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