Search results for "Molecular chemistry"
showing 10 items of 1103 documents
Hydroquinone derivatives from the marine-derived fungus Gliomastix sp.
2017
Eight new hydroquinone derivatives, gliomastins A–D (1–4), 9-O-methylgliomastin C (5), acremonin A 1-O-β-D-glucopyranoside (6), gliomastin E 1-O-β-D-glucopyranoside (7), and 6′-O-acetyl-isohomoarbutin (8), together with seven known analogues were isolated from the marine-derived fungus Gliomastix sp. Their structures were elucidated by extensive spectroscopic analysis including 1D and 2D NMR measurements aided by DFT NMR calculations as well as MS data. TDDFT-ECD and OR calculations were performed to determine the absolute configurations of 1 and the aglycones of 6 and 7. Compound 1 features a novel skeleton, biogenetically derived from a Diels–Alder reaction between derivatives of 11 and 1…
Phytochemical Profile and Antioxidant Activity of the Aerial Part Extracts from Matthiola incana subsp. rupestris and subsp . pulchella ( Brassicacea…
2021
As part of a project aimed at investigating the Matthiola taxa endemic to Sicily (Italy), this study focused on Matthiola incana, an edible species used in the traditional medicine of various countries. Herein, the characterization of phenolic and volatile compounds, the antioxidant capacity in vitro (1,1-diphenyl-2-picrylhydrazil (DPPH), reducing power and Fe2+ chelating activity assays) and the toxicity test (Artemia salina lethality bioassay) of the hydroalcoholic extracts from the aerial parts of M. incana subsp. rupestris from Mt. Pellegrino (Palermo) and Mt. Erice (Trapani), and of M. incana subsp. pulchella are reported. The results are compared with those previously shown for M. inc…
New antimicrobial metabolites from the medicinal herb Artemisia herba-Alba
2019
Artemisia herba-alba is widely used in traditional medicines for the treatment of several diseases. From the aerial parts organic extract of A. herba-alba, two new compounds, 1,3,8-trihydroxyeudesm-4-en-7α,11βH-12,6α-olide (1) and 5-β-D-glucopyranosyloxy-7-methoxy-6H-benzopyran-2-one (2), respectively, together with five known metabolites: 3α,8β-dihydroxygermacr-4(15),9(10)-dien-7β,11αH,12,6α-olide (3), 1β,8α-dihydroxy-11α,13-dihydrobalchanin (4), 11-epiartapshin (5), tomenin (6) and benzoic acid, p-(β-D-glucopyranosyloxy)-methyl ester (7), were isolated and identified. The chemical structures were proven depending upon spectroscopic analysis, including 1 D/2D NMR as and ESI-MS…
Neo-clerodane diterpenoids from Conyza pyrrhopappa Sch.Bip. ex A.Rich
2019
Two hitherto unknown neo-clerodane-type diterpenoids along with twelve known compounds have been isolated from Conyza pyrrhopappa Sch.Bip. ex A.Rich, a medicinal plant traditionally used across tropical Africa to relieve fever. The structures of isolates have been elucidated by a combination of spectroscopic techniques. The crude extract and the isolated compounds were evaluated in the Hela-S3 cell line and in a panel of microorganisms (bacteria and fungi) at concentrations up to 50 µg/mL. The new compounds were inactive while the pentamethylated flavonoids showed low to significant activity against the cancer cell line used. However, none of the samples showed any activity against the test…
Cytotoxic alkaloids from the root of Zanthoxylum paracanthum (mildbr) Kokwaro
2021
Chemical investigation of the root of Zanthoxylum paracanthum afforded 1 new alkamide derivative, (2E,4E)-6-oxo-N-isobutyldeca-2,4-dienamide (1) together with 10 known congeners including one pheno...
Binding Profiles of Self-Assembled Supramolecular Cages from ESI-MS Based Methodology
2018
Confined molecular environments have peculiar characteristics that make their properties unique in the field of biological and chemical sciences. In recent years, advances in supramolecular capsule and cage synthesis have presented the possibility to interpret the principles behind their self‐assembly and functions, which has led to new molecular systems that display outstanding properties in molecular recognition and catalysis. Herein, we report a rapid method based on ESI‐MS to determine the binding profiles for linear saturated dicarboxylic acids in a series of different cages. The cages were obtained by self‐assembly of modified tris(pyridylmethyl)amine (TPMA) complexes and diamines cho…
Cyclotriveratrylene-Containing Porphyrins
2016
International audience; The C-3-symmetric cyclotriveratrylene (CTV) was covalently bonded via click chemistry to 1, 2, 3, and 6 zinc(II) porphyrin units to various host for C-60. The binding constants, Ka, were measured from the quenching of the porphyrin fluorescence by C-60. These constants vary between 400 and 4000 M-1 and are considered weak. Computer modeling demonstrated that the zinc(II) porphyrin units, [Zn], exhibit a strong tendency to occupy the CTV cavity, hence blocking the access for C-60 to land on this site. Instead, the pincer of the type [Zn]-[Zn] and in one case [Zn]-CTV, were found to be the most probable geometry to promote host-guest associations in these systems.
CCDC 1524058: Experimental Crystal Structure Determination
2017
UDAKUI : 6,12,18,24-tetramethoxy-2,8,14,20-tetrapropyl-4,10,16,22-tetrahydroxycalix[4]arene acetone solvate Space Group: P21/n, Cell: a 11.7707(4)Å b 17.4447(6)Å c 21.7775(7)Å, α 90.00° β 105.261(2)° γ 90.00° Work published 2017 via Cambridge Crystallographic Data Centre.
Low-generation dendrimers with a calixarene core and based on a chiral C2-symmetric pyrrolidine as iminosugar mimics
2012
The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C2-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supramolecular properties of calixarenes with the advantage of a dend…
The Structural Diversity of Benzofuran Resorcinarene Leads to Enhanced Fluorescence
2014
An unexpected and previously unknown resorcinarene mono-crown with a fused benzofuran moiety in its macrocyclic core was obtained as a byproduct from a bridging reaction of tetramethoxy resorcinarene with tetraethylene glycol ditosylate. The formation of the fused benzofuran moiety in the resorcinarene macrocycle resulted in a unique rigid and puckered boat conformation, as shown by XRD studies in the solid state. Modification of the macrocycle was also observed to affect the photophysical properties in solution by enhancing the fluorescence brightness compared with a conventional resorcinarene macrocycle. The fluorescent properties enabled unique detection of structural features, that is, …