Carbocyclization in natural products. III. Brominative cyclization of dehydrosaussurea lactone and costunolide

1980 ◽  
Vol 58 (5) ◽  
pp. 447-449 ◽  
Author(s):  
Tikam C. Jain ◽  
Calvin M. Banks
Keyword(s):  
Natural Products ◽  
Spectral Data ◽  
Room Temperature ◽  
Aqueous Acetone

Treatment of dehydrosaussurea lactone 4 and costunolide 1 with N-bromosuccinimide (NBS) in aqueous acetone at room temperature furnished bromolactones 6, 7, and 8. Structural evidence for these bromolactones rests upon spectral data and transformation to the hydrogenated bromolactones 9, 10, and 11. The latter were found identical with the corresponding products obtained by the brominative cyclization of dihydrocostunolide 2.

scholarly journals Natural products isolated from Casimiroa

2020 ◽  
Vol 18 (1) ◽  
pp. 778-797
Author(s):  
Khun Nay Win Tun ◽  
Nanik Siti Aminah ◽  
Alfinda Novi Kristanti ◽  
Hnin Thanda Aung ◽  
Yoshiaki Takaya
Keyword(s):  
Natural Products ◽  
Spectral Data ◽  
Aromatic Compounds ◽  
Biological Activities ◽  
Chemical Constituents ◽  
Quinoline Alkaloids

AbstractAbout 140 genera and more than 1,600 species belong to the Rutaceae family. They grow in temperate and tropical zones on both hemispheres, as trees, shrubs, and herbs. Casimiroa is one of the genera constituting 13 species, most of which are found in tropical and subtropical regions. Many chemical constituents have been derived from this genus, including quinoline alkaloids, flavonoids, coumarins, and N-benzoyltyramide derivatives. This article reviews different studies carried out on aromatic compounds of genus Casimiroa; their biological activities; the different skeletons of coumarins, alkaloids, flavonoids, and others; and their characteristic NMR spectral data.

scholarly journals Mechanically induced solvent-free esterification method at room temperature

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5080-5085
Author(s):  
Lei Zheng ◽  
Chen Sun ◽  
Wenhao Xu ◽  
Alexandr V. Dushkin ◽  
Nikolay Polyakov ◽  
...  
Keyword(s):  
Natural Products ◽  
Carboxylic Acids ◽  
Late Stage ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Solvent Free ◽  
Mild Conditions

We have developed I2/KH2PO2 and KI/P(OEt)3 strategy syntheses of esters from carboxylic acids and alcohols through different reaction mechanisms. The advantages of present protocol: mild conditions and late-stage diversification of natural products.

scholarly journals SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF 7-HYDROXY-3',4'-DIMETHOXYFLAVONE

2012 ◽  
Vol 12 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Elfi Susanti VH ◽  
Sabirin Matsjeh ◽  
Tutik Dwi Wahyuningsih ◽  
Mustofa Mustofa ◽  
Tri Redjeki
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Sodium Hydroxide ◽  
Spectral Data ◽  
1H Nmr ◽  
13C Nmr ◽  
Room Temperature ◽  
Antioxidant Activities ◽  
Oxidative Cyclization ◽  
Dpph Method

Synthesis of flavones and their derivatives has attracted considerable attention due to their significant pharmaceutical effects. 7-hydroxy-3',4'-dimethoxyflavone has been synthesized and its antioxidant activity has been investigated. Flavone was synthesized by oxidative cyclization of chalcone. 2',4'-dihydroxy-3,4-dimethoxychalcone was prepared by Claisen-Schmidt condensation of 2,4-dihydroxyacetophenones with 3,4-dimethoxybenzaldehydes in the presence of aqueous solution of sodium hydroxide and ethanol at room temperature. Oxidative cyclization of 2',4'-dihydroxy-3,4-dimethoxychalcone was done by using I2 catalyst in DMSO to form 7-hydroxy-3',4'-dimethoxyflavone. The synthesized compounds were characterized by means of their UV-Vis, IR, 1H-NMR and 13C-NMR spectral data. The compound was tested for their antioxidant activities by DPPH method.

Broadening and shifting of the depolarized component of the Raman Q branch in D2 at room temperature

1995 ◽  
Vol 73 (7-8) ◽  
pp. 530-536 ◽  
Author(s):  
P. M. Sinclair ◽  
P. Duggan ◽  
J. R. Drummond ◽  
A. D. May
Keyword(s):  
Spectral Data ◽  
Direct Measurement ◽  
Room Temperature ◽  
Theoretical Calculations

We report the first direct measurement of the broadening and shifting of the depolarized component of the Raman Q branch in D2. Spectral data were recorded from 1.5 to 12 amagat at 305.2 K. Both the measured broadening and shifting of the depolarized component are significantly different from that for the polarized Q branch. These results can be used as a check of theoretical calculations when they become available. Here they are used to correct previously reported values of the broadening of the polarized part of the Q-branch spectrum. Measured values of the ratio of the depolarized to polarized intensity for the Q-branch lines are also given.

Assessment of the performance of quantitative feature-based transfer learning LIBS analysis of chromium in high temperature alloy steel samples

2020 ◽  
Vol 35 (11) ◽  
pp. 2639-2648
Author(s):  
Fu Chang ◽  
Huili Lu ◽  
Hao Sun ◽  
Jianhong Yang
Keyword(s):  
Hilbert Space ◽  
High Temperature ◽  
Regression Model ◽  
Spectral Data ◽  
Transfer Learning ◽  
Alloy Steel ◽  
Room Temperature ◽  
High Temperature Alloy ◽  
Feature Based ◽  
Calibration Samples

The spectral data of calibration samples at room temperature and the spectral data of uncalibrated samples at high temperature are together transferred into a Hilbert space where an LIBS regression model is established.

scholarly journals Phytochemical Investigation and Anticonvulsant Activity of Paeonia parnassica Radix

2007 ◽  
Vol 2 (4) ◽  
pp. 1934578X0700200
Author(s):  
Marina Kritsanida ◽  
Prokopios Magiatis ◽  
Alexios-Leandros Skaltsounis ◽  
James P. Stables
Keyword(s):  
Natural Products ◽  
Spectral Data ◽  
Anticonvulsant Activity ◽  
Treatment Of Epilepsy ◽  
Phytochemical Investigation ◽  
First Time

Based on traditional reports of the use of plants of the genus Paeonia in the treatment of epilepsy, we have screened extracts of the roots of three Greek Paeonia species ( P. parnassica, P. mascula subsp. hellenica, P. clusii subsp. clusii) for anticonvulsant activity. This led to the identification of some interesting prophylactic anticonvulsant activity of the extracts of P. parnassica. From the roots of this species, seventeen compounds were subsequently isolated and identified. Amongst these, seven contained the characteristic cage-like terpenic skeleton that is found only in plants of the genus Paeonia. Two of the above products: 4- O-methylpaeoniflorin (1) and paeonidanin (2) are described for the first time as natural products. The structures of all compounds have been elucidated on the basis of their spectral data.

Novel Diastereoselective Synthesis of 1-Trimethylgermyl-1-alkenes by Hydrolysis of α-Trimethylgermylzirconacyclopentenes

2020 ◽  
Vol 5 (2) ◽  
pp. 161-163
Author(s):  
Narayan G. Bhat ◽  
Maria Villarreal
Keyword(s):  
Low Temperature ◽  
Spectral Data ◽  
Room Temperature ◽  
Nitrogen Atmosphere ◽  
Terminal Alkynes ◽  
Diastereoselective Synthesis ◽  
Butyl Lithium ◽  
Hydrolysis Of

1-Trimethyl-1-germylalkynes were synthesized by deprotonation of terminal alkynes with n-butyl lithium at low temperature followed by treatment with trimethylgermyl chloride under nitrogen atmosphere. The reagent system Cp2ZrCl2/2EtMgBr converts 1-trimethylgermyl-1-alkynes into α- trimethylgermylzirconacyclopentenes at -78 ºC for 1 h followed by stirring at room temperature overnight. These novel intermediates are hydrolyzed at 0 ºC for an hour to provide the corresponding (Z)-1-trimethylgermyl-1-alkenes in good yields (74-85%) and in high stereochemical purities (> 98%) as evidenced by 13C spectral data.

Acyl-und Alkylidenphosphane, XV 2.2-Dimethylpropylidinphosphan, eine stabile Verbindung mit einem Phosphoratom der Koordinationszahl 1/ Acyl- and Alkylidenephosphines, XV 2,2-Dimethylpropvlidynephosphine, a Stable Compound with a Phosphorus Atom of Coordination Number 1

1981 ◽  
Vol 36 (1) ◽  
pp. 16-19 ◽  
Author(s):  
Gerd Becker ◽  
Gudrun Gresser ◽  
Werner Uhl
Keyword(s):  
Mass Spectrum ◽  
Sodium Hydroxide ◽  
Coordination Number ◽  
Spectral Data ◽  
Phosphorus Atom ◽  
Room Temperature ◽  
Stable Compound

Abstract In the presence of small amounts of solid sodium hydroxide, [2,2-dimethyl-l-(trimethylsiloxy)propylidene]-trimethylsilylphosphine reacts at + 20 °C to give hexamethyldisiloxane and 2,2-dimethylpropylidynephosphine (2). In contrast to similar alkylidynephosphines this compound is stable at room temperature. The IR and mass spectrum are discussed, and 1H, 13C and 31P NMR spectral data are given.

New Frond Exudate Flavonoids From Cheilanthoid Ferns

1991 ◽  
Vol 46 (5-6) ◽  
pp. 325-330 ◽  
Author(s):  
Eckhard Wollenweber ◽  
James N. Roitman
Keyword(s):  
Natural Products ◽  
Spectral Data ◽  
The Novel ◽  
Flavonoid Aglycones ◽  
Cheilanthoid Ferns

A series of new flavonoid aglycones have been identified in the frond exudates of the fern Cheilanthes argentea, in five species of Notholaena, in Pityrogramma triangularis, and in Platyzoma microphylla. These aglycones comprise several rare flavonoids and five novel natural products: 5,7,8-trihydroxy-3-methoxy-6-methyl flavone, 3,5,2′-trihydroxy-7,8,4′-trimethoxy flavone, 5,2′-dihydroxy-3,7,8-trimethoxy flavone, 5,7,4′-trihydroxy-2′-methoxy flavanone, and 3,5,4′-trihydroxy-6,7,8-trimethoxy flavone. The novel flavonoids were characterized by their N M R spectral data

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