Search results for "hydroquinone"
showing 10 items of 49 documents
ESR, ENDOR and TRIPLE resonance studies on radical reactions of 1,4-benzoquinone and 1,4-hydroquinone in alkaline methanol and liquid ammonia
1990
The relative signs and absolute values of the hyperfine coupling constants of different methoxy-1,4-benzoquinones were measured by ESR, ENDOR and TRIPLE resonance spectroscopy. Reactions of 1,4-benzoquinone and 1,4-hydroquinone with methanol took place in alkaline methanol, giving rise to methoxy-substituted 1,4-benzoquinones. The same substitution reaction occurred in a mixture of ammonia and methanol. The reactions depended on temperature and the alkali concentration. Coupling constants were assigned by the modified additivity relationship method. An extremely small line width of 0.014 G was measured in the ESR spectrum of deuterated 2,5-dimethoxy-1,4-benzoquinone.
CCDC 1994294: Experimental Crystal Structure Determination
2021
Related Article: Ali Sanda Bawa, Rita Meunier-Prest, Yoann Rousselin, Jean-Pierre Couvercelle, Christine Stern, Bernard Malézieux, Marcel Bouvet|2021|CrystEngComm|23|6418|doi:10.1039/D1CE00929J
CCDC 2063384: Experimental Crystal Structure Determination
2021
Related Article: Ali Sanda Bawa, Rita Meunier-Prest, Yoann Rousselin, Jean-Pierre Couvercelle, Christine Stern, Bernard Malézieux, Marcel Bouvet|2021|CrystEngComm|23|6418|doi:10.1039/D1CE00929J
Hydroxylation and conjugation of phenol by the frog Rana temporaria.
1985
1. Frogs injected with phenol excrete 67–95% of dose in 15h; 32–87% of dose are metabolites.2. Metabolites identified were phenyl sulphate (15–44% of dose), phenyl glucuronide (10–25% of dose), catechol sulphate (up to 7% of dose), quinol sulphate (1–25% of dose), resorcinol and catechol (traces).
In vivoInvestigation of Plant-Cell Metabolism by means of natural-abundance13C-NMR spectroscopy
1994
Based on the natural abundance of 13C, in vivo13C-NMR was used for the first time to monitor the metabolism of sucrose and hydroquinone (1) in cell suspensions of the plant Rauwolfia serpentina (L.) BENTH. ex KURZ. Cells converted sucrose extracellularly into α-D- and β -D-glucose as well as into β -D-fructofuranose and β -D-fructopyranose, respectively. The sugar mixture was completely taken up by the cells after 4 days. Hydroquinone fed at that time resulted in optimum conversion into its β -D-glucoside arbutin (2) within 10 h. A further metabolite, the primeveroside (3) of hydroquinone, appeared as a trace compound after 10 h. The formation of this diglycoside can be increased by further…
Strukturuntersuchung von Polyestern durch direkten Abbau im massenspektrometer, 5. Polyester aus Terephthalsäure und/oder Bernsteinsäure und Hydrochi…
1978
The structure and thermal degradation behaviour of polyesters from terephthalic and/or succinic acid and hydroquinone were investigated by pyrolysis mass spectrometry. Poly(oxysuccinyloxy-1,4-phenylene) (2) undergoes cleavage of the ester bond (Eq. (vii)) as a very selective pyrolysis mechanism at 310°C, whereas the thermally more stable poly(oxyterephthaloyloxy-1,4-phenylene) (1) starts to degrade above 400°C and yields pyrolysis products with phenyl (Eq. (iv)), p-hydroxyphenyl (Eq. (iii)), benzoyl (Eq. (iiv)) and carboxylic end groups. A calibration curve of the intensities of monomer specific fragments, obtained from pyrolysis mass spectra of polyesters from terephthalic acid, succinic a…
CCDC 1994293: Experimental Crystal Structure Determination
2021
Related Article: Ali Sanda Bawa, Rita Meunier-Prest, Yoann Rousselin, Jean-Pierre Couvercelle, Christine Stern, Bernard Malézieux, Marcel Bouvet|2021|CrystEngComm|23|6418|doi:10.1039/D1CE00929J
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…
High-Yield Formation of Arbutin from Hydroquinone by Cell-Suspension Cultures ofRauwolfia serpentina
1992
High-density cell-suspension cultures of Rauwolfia serpentina cultivated in a nutrition medium optimized for the production of the glucoalkaloid raucaffricine synthesize hydroquinone glycosides from continuously added hydroquinone with a total yield of 23.87 g/1 (18 g/1 of arbutin and 5.87 g/1 of a hydroquinone diglycoside) in 7 days. This arbutin production is by far the highest formation of a natural product by plant-cell-culture systems reported to date.
Pentadecamer 2,5-Dipropoxy-1,4-phenylenevinylene
2002
The conjugated, all-(E)-configured pentadecamer 2,5-dipropoxy-1,4-phenylenevinylene 1j was prepared by a multistep synthesis on the basis of hydroquinone. The procedure consists of a general method for the repetitive extension of oligo(phenylenvinylene) chains by two styryl units (7a ⇄ 10 ⇄ 12 ⇄ 14). The relatively rigid oligomer 1j represents a molecular wire of about 100 A. The absorption of 1j provides a proof for the convergence theory for electronic properties of conjugated oligomers with increasing number of repeat units. The corresponding conjugated polymer 1p with the same substitution matches the values which were extrapolated from the oligomer series 1a−1j. (© Wiley-VCH Verlag Gmb…