scholarly journals Synthesis of Cyclobutane Analogue 4: Preparation of Purine and Pyrimidine Carbocyclic Nucleoside Derivatives

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3235 ◽  
Author(s):  
Noha Hasaneen ◽  
Abdelaziz Ebead ◽  
Muhammad Murtaza Hassan ◽  
Hanan Afifi ◽  
Howard Hunter ◽  
...  
Keyword(s):  
2D Nmr ◽  
Major Product ◽  
Trans Orientation ◽  
Charge Delocalization ◽  
Pyrimidine Nucleosides ◽  
Nmr Data ◽  
Relative Stereochemistry ◽  
Steric Factors ◽  
Nmr Techniques ◽  
Carbocyclic Nucleoside

The coupling of 2-bromo-3-benzoyloxycyclobutanone with purine under basic conditions produces two regioisomers consisting of the N-7 and N-9 alkylated products in equal amounts in their racemic forms. The distribution of the isomers is consistent with the charge delocalization between the N-7 and N-9 positions of the purinyl anion. The structural assignments and relative stereochemistry of each regioisomer were based on 1 and 2D NMR techniques. The relative stereochemistry of the C-2 and C-3 substituents in each regioisomer was the trans orientation consistent with steric factors in the coupling step. The N-9 regioisomer was reduced with sodium borohydride to give the all trans cyclobutanol as the major product in a stereoselective manner. The alcohol was debenzoylated with sodium methoxide in a transesterification step to give the nucleoside analogue. The regioisomeric pyrimidine nucleosides were prepared by Vorbrüggen coupling of the 3-hydroxymethylcyclobutanone triflate with either thymine or uracil followed by stereoselective hydride addition. Regiospecificity of the coupling at the N-1 position was observed and stereoselective reduction to the trans-disubstituted cyclobutanol structure assignments was based on NMR data.

scholarly journals A New Trinor-guaiane Sesquiterpene from an Indonesian Soft Coral Anthelia sp

2015 ◽  
Vol 10 (11) ◽  
pp. 1934578X1501001 ◽  
Author(s):  
Novriyandi Hanif ◽  
Anggia Murni ◽  
Marie Yamauchi ◽  
Masahiro Higashi ◽  
Junichi Tanaka
Keyword(s):  
Soft Coral ◽  
Optical Rotation ◽  
2D Nmr ◽  
Planar Structure ◽  
Nmr Data ◽  
Relative Stereochemistry ◽  
Absolute Stereochemistry

A new trinor-guaiane sesquiterpene has been isolated from an Indonesian soft coral Anthelia sp. The planar structure, possessing an octahydroazulene skeleton, and relative stereochemistry were established by analyzing 1D and 2D NMR data, including NOE experiments. Its absolute stereochemistry was elucidated to be 1 S, 4 S, 7 R, and 10 R by comparing observed and calculated optical rotation values. The new compound showed weak cytotoxicity against NBT-T2 cells.

Two New Limonoids With A 3-O-β-Tigloyl Group From The Seeds Of The Chinese Mangrove Xylocarpus Granatum

2007 ◽  
Vol 62 (6) ◽  
pp. 859-862 ◽  
Author(s):  
Jun Wu ◽  
Minyi Li ◽  
Si Zhang ◽  
Qiang Xiao ◽  
Qingxin Li
Keyword(s):  
Spectroscopic Data ◽  
2D Nmr ◽  
Nmr Data ◽  
Xylocarpus Granatum ◽  
Nmr Techniques ◽  
Noesy Spectra ◽  
C Nmr

A new mexicanolide and a new phragmalin, named 30α-hydroxyl xylogranatin A and xylogranatin E2, respectively, have been isolated from the seeds of a Chinese mangrove Xylocarpus granatum. Their structures were identified on the basis of spectroscopic data. Each of them has a 3-O-β -tigloyl group. The first complete assignments of 1H and 13C NMR data for these limonoids were achieved by means of 2D NMR techniques, including 1H-1H COSY, HSQC, HMBC and NOESY spectra

scholarly journals Subereaphenol A, a new Cytotoxic and Antimicrobial Dibrominated Phenol from the Red Sea Sponge Suberea Mollis

2008 ◽  
Vol 3 (2) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Lamiaa A. Shaala ◽  
Sherief I. Khalifa ◽  
Mostafa K. Mesbah ◽  
Rob W. M. Van Soest ◽  
Diaa T. A. Youssef
Keyword(s):  
High Resolution ◽  
Red Sea ◽  
2D Nmr ◽  
Antimicrobial Activities ◽  
Mass Spectral ◽  
Nmr Data ◽  
Nmr Techniques ◽  
Red Sea Coast ◽  
Sea Coast ◽  
Resolution Mass

An investigation of the sponge Suberea mollis collected at the Egyptian Red Sea coast afforded a new cytotoxic and antimicrobial dibrominated phenol, subereaphenol A (1), together with the previously reported compounds 2-(3′,5′-dibromo-2′-hydroxy-4′-methoxyphenyl)acetamide (2), dibromoverongiaquinol (3), bromochloroverongiaquinol (4), and 2-(3′,5′-dibromo-4′-ethoxy-1′-hydroxy-4′-methoxy-2′,5′-cyclohexadien-1-yl)acetamide (5). The structure of the compounds was determined by a combination of 1D and 2D NMR techniques and High-resolution mass spectral determinations. Complete and new NMR data for the known compounds has been reported. The cytotoxic and the antimicrobial activities of the compounds are reported.

Xylogranatin E, a New Phragmalin with a Rare Oxygen Bridge between C1 and C29, from the Fruit of a Chinese Mangrove Xylocarpus granatum

2007 ◽  
Vol 62 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Jun Wu ◽  
Haixin Ding ◽  
Minyi Li ◽  
Si Zhang
Keyword(s):  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Oxygen Bridge ◽  
Nmr Data ◽  
Xylocarpus Granatum ◽  
Complete Assignment ◽  
Nmr Techniques ◽  
Noesy Spectra ◽  
C Nmr

Xylogranatin E, the second phragmalin with a rare oxygen bridge between C1 and C29 found in nature, was isolated from the fruit of a Chinese mangrove, Xylocarpus granatum. Its structure was determined by spectroscopic analysis. Complete assignment of 1H and 13C NMR data of xylogranatin E was achieved by 2D NMR techniques, including 1H-1H COSY, HSQC, HMBC and NOESY spectra.

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.

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.

scholarly journals Synthesis and Physicochemical Properties of [(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-thiophen-5-yl-substituted Tetrapyrazinoporphyrazine with Magnesium(II) Ion

2021 ◽  
Vol 11 (6) ◽  
pp. 2576
Author(s):  
Sebastian Lijewski ◽  
Jiří Tydlitát ◽  
Beata Czarczynska-Goslinska ◽  
Milan Klikar ◽  
Jadwiga Mielcarek ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
2D Nmr ◽  
Nmr Studies ◽  
Oxygen Formation ◽  
Nmr Techniques ◽  
Flash Column Chromatography ◽  
Photochemical Stability ◽  
Singlet Oxygen Formation ◽  
Very High

Tetrapyrazinoporphyrazine with peripheral menthol-thiophenyl substituents was synthesized using Linstead conditions and purified by flash column chromatography. The optimized synthetic and purification procedures allowed us to obtain a new macrocycle with 36% yield. Tetrapyrazinoporphyrazine derivative was characterized by UV–Vis and NMR spectroscopy, as well as MS spectrometry. Complex NMR studies using 1D and 2D NMR techniques allowed the analysis of the bulky menthol-thiophenyl substituted periphery of the new macrocycle. Further, photochemical stability and singlet oxygen quantum yield were determined by indirect method with diphenylisobenzofuran. The new tetrapyrazinoporphyrazine revealed low generation of singlet oxygen with a quantum yield of singlet oxygen formation at 2.3% in dimethylformamide. In turn, the macrocycle under irradiation with visible light presented very high stability with quantum yield for photostability of 9.59 × 10−6 in dimethylformamide, which figures significantly exceed the border for its classification as a stable porphyrinoid (10−4–10−5).

Flavon- and Flavonolglycosides from Achillea pannonica Scheele

2001 ◽  
Vol 56 (7-8) ◽  
pp. 521-525 ◽  
Author(s):  
Denata Kasaj ◽  
Liselotte Krenn ◽  
Sonja Prinz ◽  
Antje Hüfner ◽  
Shi Shan Yuc ◽  
...  
Keyword(s):  
Methanolic Extract ◽  
2D Nmr ◽  
Flavonoid Glycosides ◽  
Spectroscopic Methods ◽  
Esi Ms ◽  
Aerial Parts ◽  
Nmr Techniques ◽  
Chemotaxonomic Study ◽  
First Time ◽  
C Nmr

The detailed investigation of a methanolic extract of aerial parts of Achillea pannonica SCHEELE. within a chemotaxonomic study led to the isolation of 6 flavonoid glycosides. Besides rutin, apigenin-7-O-glucopyranoside, luteolin-7-O-glucopyranoside, apigenin-7-O-rutinoside and acacetin-7-O-rutinoside, an unusual flavondiglucoside was isolated. Its structure was established by UV, 1HNMR and 13C NMR spectroscopic methods including 2D-NMR techniques and ESI-MS as luteolin-7,4′-O-β-diglucoside. This substance is reported for the first time in the genus Achillea. Chemotaxonomic aspects are discussed briefly

Investigation of the effect of ring size on the product distribution for the Schiff base reaction of 2-acetylcycloalkanones with diamino alkanes

1995 ◽  
Vol 73 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Raul G. Enriquez ◽  
Juan M. Fernandez-G ◽  
Ismael Leon ◽  
William F. Reynolds ◽  
Ji.-Ping Yang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Condensation Reaction ◽  
2D Nmr ◽  
Product Distribution ◽  
Major Product ◽  
Ring Size ◽  
Amino Group ◽  
Amino Groups ◽  
Similar Product ◽  
Acetyl Group

The Schiff base condensation reaction of 1,2-diaminoethane with a series of 2-acetylcycloalkanones (from cyclopentanone to cyclooctanone) has been investigated and the products characterized by two-dimensional nuclear magnetic resonance. The site of attack of the amino groups, i.e., ring ketone or acetyl ketone, is determined primarily by ring size. 2-Acetylcyclohexanone yields two products in ca. 9:1 ratio, the major product where the two amino groups attack at the ring ketones of two different cyclohexanone molecules, and the minor product where one amino group attacks one ring carbonyl of one cyclohexanone while the second amino group attacks the acetyl group of another. 2-Acetylcyclopentanone yields all three possible products with the major product involving attack at the acetyl groups of two different cyclopentanones. The corresponding reactions for 2-acetylcycloheptanone and 2-acetylcyclooctanone each give a single product corresponding to attack at the acetyl groups of two different cycloalkanones. Similar product distributions are observed for the reactions of the different 2-acetylcycloalkanones with 1,4-diaminobutane. Keywords: Schiff base reactions, diketones, 2D NMR.

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