NMR spectra

Ten new chromone derivatives were synthesized from the original 2-4-6- trihydroxyacetophenone using microwave irradiation. The product's structures were confirmed by FT-IR, 1H-NMR, and 13C-NMR spectra data. The anti-microbial activities of the obtained compounds were tested by the disc diffusion method. The results showed that most chromones have significant biological activities against Candida albicans.

10p viambani 18-06-2024 1 0   Download

Phytochemical study on the leaves of Fissistigma balansae led to the isolation of one new sesquiterpene glycoside, (3S,6E)-3-O-β-D-glucopyranosyl-8-hydroxy-3,7,11-trimethyldodeca-1,6,10-triene, and six known compounds, aromandendrane-4β,10α-diol, phloridzosid, astragalin, isoquercitrin, and rutin, acanthoside B. Their chemical structures were identified by HR-ESI-MS and NMR (1D and 2D) spectra. This is the first report of these compounds from F. balansae.

5p dianmotminh02 03-05-2024 5 1   Download

From CHCl3-soluble extract of the leaves of Taxus wallichiana (Taxaceae), collected in Lam Dong Province, five compounds were isolated and identified as sciadopitysin, ginkgetin, (S)-(+)-rhododenol, (+)-erythro-N-benzoyl3-phenylisoserine methyl ester, and (−)-α-conidendrin (5). Their chemical structures were determined by 1D and 2D NMR spectra and comparison with published data. Except for (−)-α-conidendrin, these remaining compounds were first reported of Taxus wallichiana.

6p dianmotminh02 03-05-2024 5 3   Download

One new sesquiterpene, (4S,7R,10S)-2-oxo-4,10,11-trihydroxyguaia-1(5)-ene, and five lignans, kadsuralignan J, isovaleroylbinankadsurin A, schizandrin O, futokakadsurin C and arisantetralone were isolated from the roots of Kadsura induta. Their chemical structures were revealed by MS, 1D and 2D NMR spectra in comparison with the reported data. The absolute configuration of compound 1 was determined by calculation of its theoretical ECD spectra and compared with the experimental results.

9p dianmotminh02 03-05-2024 4 2   Download

Ebook "Synthesis and characterization of glycosides (Second edition)" is a short and comprehensive study on the best known approaches for preparing the main types of glycosides. It covers synthetic pathways of challenging glycosides known as antiviral or antineoplastic drugs, and synthetic substrates used for enzymatic detection, including those used for detection of gene markers in plant biotechnology. The author pays special attention to the structural characterization of glycosides and provides the basic tools for the structural assignment through NMR, X-Ray and mass spectra techniques.

432p tracanhphuonghoa1007 22-04-2024 3 2   Download

Ebook "Computer-based structure elucidation from spectral data: The art of solving problems" is composed of three parts. Part I contains a concise description of the ACD/Structure Elucidator flow diagram, its knowledgebase, and the fundamental concepts making up the theoretical basis of CASE (Chap. 1). Different strategies regarding the application of the system depending on the specific features of the problem being solved are discussed in Chap. 2.

458p tudohanhtau1006 29-03-2024 3 1   Download

Part 1 book "Advances in chemical engineering" includes content: Application of chebyshev polynomials to calculate density and fugacity using saft equation of state to predict asphaltene precipitation conditions; based on common inverted microscope to measure UV vis spectra of single oil gas inclusions and colour analysis; challenging evaluation of the hybrid technique of chemical engineering - proton NMR technique for food engineering; modelling approach for redesign of technical processes; application potential of food protein modification,... and other contents.

334p muasambanhan09 16-03-2024 3 1   Download

In this research, five compounds were isolated from Chrysanthemum indicum L flowers and determined their structures to be Syringin (1), Dihydrosyringin (2), Benzyl-O-β-Dglucopyranoside(3), -Phenylethoxy-O-β-D-glucopyranoside(4), and (Z)-5’-Hydroxyjasmone 5’-O-β-D-Glucopyranoside(5)by analysis 1D - NMR spectra and compared to literatures.

6p vimarillynhewson 02-01-2024 8 3   Download

Phytochemical studies on the methanolic extract of Barleria prionitis Linn. collected in Luang Namtha province, Laos have led to the isolation and structural elucidation of four secondary metabolites, including two iridoid glycosides: shanzhiside methyl ester (1), barlerin (2); one sterol: stigmasterol (3); and a sterol glycoside: β-sitosterol glycoside (4). Their structures were identified by spectroscopic analyses such as 1D and 2D NMR spectra.

7p visharma 20-10-2023 5 1   Download

Miliusa velutina Dun Hook. f. et. Thoms is the rare and native plant, belongs to the Annonaceae family. The isolated compounds in Miliusa genus showed that many function groups and have diverse bioactivities. From the ethyl acetate extract of the trunk of Miliusa velutina, three compounds were isolated and determined based on 1D, 2D NMR spectra, MS and combined comparison with references.

5p viberkshire 09-08-2023 6 4   Download

Caesalpinia bonduc L. is a flowering plant belonging to Caesalpinia in the Caesalpiniaceae family. “Bonducella” the name of the species is derived from the Arabic word “Bonduce” meaning a “little ball” which indicates the globular shape of the seed.

5p vidoctorstrange 06-05-2023 4 1   Download

Five naturalsecondary metabolites as cinnamic acid (1), (+)-catechin (2), (−)-epicatechin (3), p-coumaric acid (4), and ferulic acid (5) were isolated from Amanita caesarea based on antiinflammatory activity-guided extraction. Their structures (1−5) were determined by NMR spectra as well as by comparison with previously reported literature.

4p visirius 11-01-2023 5 2   Download

Structural determination of carbohydrates is mostly performed by liquid-state NMR, and it is a demanding task because the NMR signals of these biomolecules explore a rather narrow range of chemical shifts, with the result that the resonances of each monosaccharide unit heavily overlap with those of others, thus muddling their punctual identification.

20p viginny 30-12-2022 17 3   Download

The 31P MAS NMR spectra of phosphorus-modified chabazite (P-CHA) zeolites have been observed during the hydrothermal treatment to probe the structural changes of phosphorus species in zeolites. Characteristic changes of the spectra were observed in the range of 27 ~ 42 ppm, which correlates to the hydrothermal structure changes in P-CHA zeolite

12p vironald 15-12-2022 6 2   Download

Part 1 of ebook "Spectrometric Identification of Organic Compounds (7th Edition)" provide students with knowledge about: mass spectrometry; infrared spectrometry; proton magnetic resonance spectrometry; carbon-13 NMR spectrometry; gas-phase ionization method; magnetic spector mass spectrometers; fourier transform mass spectrometer; interpretation of EI mass spectra; mass spectra of some chemical classes;...

262p colinhthu 09-08-2022 6 3   Download

The aerial of Cissus modeccoides was collected in Binh Duong province, Vietnam. The ethanolic extract from this aerial was prepared by maceration. By liquid-liquid extraction, three extracts, n-hexane, ethyl acetate, and methanol were obtained. Three known anthraquinones 1-3 and two phenolic compounds 4-5 were isolated from the ethyl acetate extract by chromatography technique.

7p vithales 19-04-2022 16 1   Download

This paper describes the isolation and structural elucidation of three flavonoids from the leaves of Wedelia trilobata. From the chloroform extract of the leaves of Wedelia trilobata (L.) Hitch., collected in district 7 fallows, fifteen compounds were isolated.

10p vikissinger 03-03-2022 14 1   Download

Sparsifloamide (1), a new sphingolipid, and sparsifloside (2), a new diglyceride galactoside, have been isolated from the ethyl acetate soluble fraction of the 80% ethanolic extract of the whole plant of Croton sparsiflorus Morong. Their structures were assigned by 1 H- and 13 C-NMR spectra and DEPT, COSY, NOESY, HMQC, HMBC, and ESI-MS experiments.

8p langthannam 29-12-2021 13 0   Download

1,3-Dipolar cycloaddition of 5-azidomethyl-3-p-substituted phenyl-1,2,4-oxadiazoles to phenyl vinyl sulfone and bismaleimide gives rise straightforwardly to 1-((3-(p-substituted) phenyl-1,2,4-oxadiazol-5-yl)methyl)-4-(phenylsulfonyl)-4,5-dihydro-1H-1,2,3-triazoles and bisdihydropyrrolo[3,4-d][1,2,3]triazole-4,6(3aH,5H)-diones. The structures of the new cycloadducts were elucidated by means of IR, NMR (1H, 13C, 2D), mass spectra, and physical characteristics (mp and Rf values). In addition, anticancer activities of the cycloadducts against MCF-7 cells were also investigated.

17p langthannam 29-12-2021 7 0   Download

The synthesis of novel zinc, cobalt, indium, and metal-free phthalocyanines carrying four 3-(4-phenyloxy)coumarins in the periphery/nonperiphery were prepared by cyclotetramerization of 3-[4-(3,4-dicyanophenyloxy)phenyl]coumarin (2)/3-[4-(2,3- dicyanophenyloxy)phenyl]coumarin (3). The novel chromogenic compounds were characterized by elemental analysis, 1 H NMR, mass spectra, F-IR, and UV-vis spectral data. The effects of the coumarin units on the zinc, indium, and metal-free phthalocyanine complexes (2a/3a, 2c/3c, 2d/3d) were also investigated.

16p langthannam 29-12-2021 14 0   Download