BF3·OEt2-Catalyzed Aldol Condensation of Steroid Sapogenins and 2-Oxoacids: A Single Step Conversion of Steroid Spiroketals into Branched α,β-Unsaturated Spirolactones

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2241-2244
Author(s):  
Martin A. Iglesias-Arteaga ◽  
Juan E. Hernández-Martínez
Keyword(s):  
Pyruvic Acid ◽  
Aldol Condensation ◽  
Aldol Reaction ◽  
Glyoxylic Acid ◽  
2D Nmr ◽  
Single Step ◽  
Side Chain ◽  
The Novel ◽  
Nmr Techniques ◽  
Plausible Mechanism

BF3·OEt2-catalyzed aldol reaction of steroid sapogenins with glyoxylic acid or pyruvic acid led to compounds in which the novel spirocyclic side chain bears an α,β-unsaturated lactone. The structures of the new spirolactones were established with the aid of combined 1D and 2D NMR techniques. A plausible mechanism is described.

E-Homolupane Derivatives Substituted in Position 17 and 22a. 1H NMR, 13C NMR and IR Spectra

1995 ◽  
Vol 60 (4) ◽  
pp. 619-635 ◽  
Author(s):  
Václav Křeček ◽  
Stanislav Hilgard ◽  
Miloš Buděšínský ◽  
Alois Vystrčil
Keyword(s):  
Nmr Spectra ◽  
2D Nmr ◽  
Coupling Constants ◽  
Side Chain ◽  
Oxidation Reactions ◽  
H Nmr ◽  
Complete Assignment ◽  
Nmr Techniques ◽  
Intramolecular Association ◽  
C Nmr

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.

scholarly journals Novel ion-binding C3 symmetric tripodal triazoles: synthesis and characterization

2014 ◽  
Vol 12 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Gábor Neumajer ◽  
Gergő Tóth ◽  
Szabolcs Béni ◽  
Béla Noszál
Keyword(s):  
2D Nmr ◽  
Ion Binding ◽  
The Novel ◽  
Spectrometric Data ◽  
Polydentate Ligands ◽  
Nmr Techniques ◽  
Sonogashira Reactions ◽  
Symmetric Ligands ◽  
Complexation Process

AbstractNovel C3 symmetric tripodal molecules were synthesized from cyclohexane 1,3,5-tricarboxylic acid. Utilizing click and Sonogashira reactions, ion-binding triazole and pyridazin-3(2H)-one units were incorporated to form polydentate ligands for ion complexation. The structures of the novel C3 symmetric derivatives were extensively characterized by 1H, 13C and 2D NMR techniques along with HRMS and IR. The copper(I)-binding potentials of these ligands were investigated by using them as additives in model copper(I)-catalysed azide-alkyne cycloaddition (CuAAC) reactions. The copper(I) complexation ability of our compound was also proved by different spectroscopic methods, such as mass spectrometry, UV and NMR spectroscopy. Based on the mass spectrometric data all of the C3 symmetric ligands formed 1:1 complex with copper(I) ion. The specific role of C3 symmetric polydentate form in the complexation process was also discussed

scholarly journals β-Elemene derivatives produced from SeO 2 -mediated oxidation reaction

2020 ◽  
Vol 7 (5) ◽  
pp. 200038
Author(s):  
Xingrui He ◽  
Xiao-Tao Zhuo ◽  
Yuan Gao ◽  
Renren Bai ◽  
Xiang-Yang Ye ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Oxidation Reaction ◽  
2D Nmr ◽  
Single Step ◽  
Easy Access ◽  
Nmr Techniques ◽  
One Step ◽  
New Compounds ◽  
Mediated Oxidation

Herein, we report the first access of β-elemene derivatives through the SeO 2 -mediated oxidation reaction. Several new compounds were isolated through such a one-step reaction, and their structures were elucidated using various 2D-NMR techniques. This method provides easy access to multiple oxidative β-elemene derivatives in one single step and represents the first modifications on cyclohexyl ring of β-elemene. It is expected to open up the opportunity for future derivatization on cyclohexyl ring of β-elemene. The new compounds obtained above showed better anti-proliferation activities than β-elemene itself on several cancer cell lines. Among them, compound 17 shows the best activity in antiproliferation assays of A549 and U-87MG cell lines.

MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis

Holzforschung ◽  
2007 ◽  
Vol 61 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mikhail Yu. Balakshin ◽  
Ewellyn A. Capanema ◽  
Hou-min Chang
Keyword(s):  
Loblolly Pine ◽  
Spectroscopic Analysis ◽  
Direct Detection ◽  
2D Nmr ◽  
Side Chain ◽  
High Concentration ◽  
Hmbc Correlation ◽  
Nmr Techniques ◽  
C Nmr ◽  
Hmbc Technique

Abstract A preparation enriched in lignin-carbohydrate fragments (LCC-AcOH) was isolated in the course of purification of loblolly pine crude milled wood lignin (MWL). The preparation contained approximately equal amounts of lignin and carbohydrates, with high amounts of arabinose and galactose compared to their levels in wood. LCC-AcOH was investigated by 2D 1H-13C (HMQC and HMBC) correlation NMR techniques and quantitative 13C NMR. The HMQC spectra allowed direct detection of phenyl glycoside, ester and benzyl ether lignin-carbohydrates linkages in high amounts. The assignment of these structures was supported by the HMBC technique. It is noteworthy that in the ester lignin-carbohydrate linkages, a uronic acid residue was attached not to the benzylic position of lignin, as commonly believed, but to the γ-position of the side chain.

Studies towards the Total Synthesis of Kadcotrione B

Synthesis ◽  
2019 ◽  
Vol 52 (05) ◽  
pp. 735-743
Author(s):  
Julakanti Satyanarayana Reddy ◽  
Marri Gangababu ◽  
Patel Manimala ◽  
Aluru Rammohan ◽  
Jillu Singh Yadav
Keyword(s):  
Total Synthesis ◽  
Michael Addition ◽  
Aldol Condensation ◽  
Aldol Reaction ◽  
Side Chain ◽  
Wacker Oxidation ◽  
Efficient Approach ◽  
Salient Features ◽  
Robinson Annulation

A convergent and efficient approach towards the total synthesis of Kadcotrione B is described. For this purpose, the syntheses of two fragments, 6/6/5-fused tricyclic ring and C-9 side chain, were accomplished. The salient features of these syntheses are the utilization of aldol condensation, Evans aldol reaction, Horner–Wadsworth–Emmons olefination, Michael addition, Robinson annulation, and Wacker oxidation.

scholarly journals Synthesis and structure of (R,S)-2-methyl-4-(4-nitrophenyl)-pyrano[3,2-c]chromen-5(4H)-one

2012 ◽  
Vol 32 (2) ◽  
pp. 239
Author(s):  
Rosica P. Nikolova ◽  
Boris Shivachev ◽  
Bozhana Mikhova ◽  
Bistra Stamboliyska ◽  
Kristina Mladenovska ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Chemical Structure ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
The Novel ◽  
Phosphoryl Chloride ◽  
Torsion Angles ◽  
X Ray ◽  
Nmr Techniques ◽  
High Yields

In this paper, the synthesis and structure of a novel pyrano[3,2-c]coumarin, which was obtained unexpectedly in a reaction of phosphoryl chloride and acenocoumarol, are presented. The chemical structure of the novel compound was elucidated by a detailed spectroscopic analysis based mainly on 1D and 2D NMR techniques. The structure was finally confirmed with a single-crystal X-ray analysis. The B3LYP/6-311+G** method correctly reproduces the bond lengths, bond angles, torsion angles, and other experimental spectroscopic data, which can be useful for investigating the characteristics of some structurally related molecules. Additionally, the title compound was obtained in high yields by performing a dehydratation reaction of acenocuomarol with acetic anhydride.  

Isolation of New Glycosides from Anemarrhena Asphodeloides Rhizome and Screening of their Anticancer Activity

2019 ◽  
Vol 16 (6) ◽  
pp. 474-477 ◽  
Author(s):  
Pham Van Khang ◽  
Nguyen Thi Hien Lan ◽  
Le Quang Truong ◽  
Mai Thi Minh Chau ◽  
Mai Xuan Truong ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Spectral Data ◽  
Cell Lines ◽  
Cancer Cell ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Ic50 Values ◽  
Nmr Techniques ◽  
Inhibitory Activities ◽  
Anemarrhena Asphodeloides

In this report, two new steroidal glycosides were isolated and determined from n-butanol fraction of A.asphodeloides. The structures were confirmed in comparison with the spectral data of known compounds by using different spectroscopic analysis approaches including 1D & 2D-NMR techniques and HRMS. The anti-proliferation screening against cancer cell lines A549 and HeLa indicated that compound 1 exhibited good inhibitory activities with IC50 values of 0.79 and 0.55 µg/mL, respectively.

Nuclear Magnetic Resonance Spectroscopic Behaviour of Some Selective Natural Flavonoids: A Look Through

2020 ◽  
Vol 17 (2) ◽  
pp. 185-196
Author(s):  
Shyamal K. Jash ◽  
Dilip Gorai ◽  
Lalan C. Mandal ◽  
Rajiv Roy
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Natural Products ◽  
Magnetic Resonance ◽  
Hard Core ◽  
2D Nmr ◽  
Vital Role ◽  
Spectral Technique ◽  
Nmr Techniques ◽  
Significant Class ◽  
Nuclear Magnetic

Flavonoids are considered as a significant class of compounds among the natural products, exhibiting a variety of structural skeletons as well as multidirectional biological potentials. In structural elucidations of natural products, Nuclear Magnetic Resonance (NMR) spectroscopy has been playing a vital role; the technique is one of the sharpest tools in the hands of natural products chemists. The present resume deals with hard-core applications of such spectral technique, particularly in structural elucidation of flavonoids; different NMR techniques including 1H-NMR, 13C-NMR, and 2D-NMR [viz. 1H-1H COSY, COLOC, HMBC, HMQC] are described in detail.

Six-Sided Heptaporphyrin Array: Towards a Nano-Sized Cube

2004 ◽  
Vol 69 (5) ◽  
pp. 996-1008 ◽  
Author(s):  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Single Step ◽  
One Pot ◽  
H Nmr ◽  
The Core ◽  
Nmr Techniques ◽  
Axial Vertex

A strategy in preparing a family of hexameric porphyrin cubes based on the interplay of Sn(IV)-O and Ru(II)-N interactions is described. In this first iteration, we have prepared the heptamer [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 (4 = (E)-(3-(4-pyridyl)acrylate)) constituting a 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) core and 5,10,15,20-tetraphenylporphyrin (TPP) faces and compared its formation by stepwise and "one-pot" strategies where up to nine components are assembled in a single step in a regiospecific manner. In one example, the heptamer is formed around the template [SnIV(TPyP)·(4)2] bearing pyridine groups in which the nitrogens radiate octahedrally along each vertex. The ability to modulate the axial vertex through choice of pyridine is also demonstrated. 1H NMR measurements on [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 indicate that the protons on the core template are extremely shielded as a result of the anisotropy of the peripheral porphyrin units. Various NMR techniques, including NOESY experiments, have been used to characterise the heptamer in solution.

scholarly journals Sulfanyl Porphyrazines with Morpholinylethyl Periphery—Synthesis, Electrochemistry, and Photocatalytic Studies after Deposition on Titanium(IV) Oxide P25 Nanoparticles

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2280
Author(s):  
Tomasz Koczorowski ◽  
Wojciech Szczolko ◽  
Anna Teubert ◽  
Tomasz Goslinski
Keyword(s):  
Diclofenac Sodium ◽  
2D Nmr ◽  
Oxide Nanoparticles ◽  
Electrochemical Studies ◽  
Macrocyclic Compounds ◽  
Active Pharmaceutical Ingredients ◽  
Pharmaceutical Ingredients ◽  
Vis Spectroscopy ◽  
Singlet Oxygen Quencher ◽  
Nmr Techniques

The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthesized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available P25 titanium(IV) oxide nanoparticles. The obtained macrocyclic compounds were broadly characterized by ESI MS spectrometry, 1D and 2D NMR techniques, UV–Vis spectroscopy, and subjected to electrochemical studies. Both hybrid materials, consisting of porphyrazine derivatives embedded on the titanium(IV) oxide nanoparticles’ surface, were characterized in terms of particle size and distribution. Next, they were subjected to photocatalytic studies with 1,3-diphenylisobenzofuran, a known singlet oxygen quencher. The applicability of the obtained hybrid material consisting of titanium(IV) oxide P25 nanoparticles and magnesium(II) porphyrazine derivative was assessed in photocatalytic studies with selected active pharmaceutical ingredients, such as diclofenac sodium salt and ibuprofen.

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