Results 291 to 300 of about 839,062 (317)

Absolute Configuration of Scyphostatin

Organic Letters, 2000
[reaction: see text] The absolute configuration of the side chain of scyphostatin (1) has been established. The chemical degradation of 1 gave 4 and 9, which correspond to the C7'-C12' and C13'-C16' fragments of the natural products, respectively. The spectroscopic data and [alpha]D values of both compounds were compared to those of authentic samples ...
, Saito, , Tanaka, , Fujimoto, , Kogen
openaire   +2 more sources

The absolute configuration of glucosamine

Biochimica et Biophysica Acta (BBA) - General Subjects, 1967
Abstract The absolute configuration of α- D -glucosamine hydrochloride has been determined by X-ray diffraction. The calculated Bijvoet differences in the intensity of the inverse reflections, arising out of the anomalous dispersion effect of the chlorine atom, agree well with those experimentally measured.
G N, Ramachandran, R, Chandrasekaran, K S, Chandrasekaran   +2 more
openaire   +2 more sources

Absolute Configuration of the Prostaglandins

Nature, 1966
A stereochemical diagram depicts the absolute configuration of the prostaglandins and of its parent molecule prostanoic acid. The systematic name of prostaglandin E1 is (-) 11 alpha 15(S)-dihydroxy-9-oxo-13trans-prostanoic acid.
D H, Nugteren, D A, Van Dorp, S, Bergström, M, Hamberg, B, Samuelsson   +4 more
openaire   +2 more sources

Absolute configuration of strictosidinic acid

Acta Crystallographica Section C Crystal Structure Communications, 2012
The absolute configuration of strictosidinic acid, (2S,3R,4S)-3-ethenyl-2-(β-D-glucopyranosyloxy)-4-{[(1S)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl]methyl}-3,4-dihydro-2H-pyran-5-carboxylate, was determined from its sodium chloride trihydrate, poly[[diaqua((2S,3R,4S)-3-ethenyl-2-(β-D-glucopyranosyloxy)-4-{[(1S)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b ...
Rosane de P, Castro, Carolina da S, Matos, Cláudia A, do Nascimento, Cecília M A, Oliveira, Lucília, Kato, Luciano M, Lião, José R, Sabino   +6 more
openaire   +2 more sources

Absolute Configuration of Amphidinin A

Journal of Natural Products, 2014
The absolute configurations at six stereogenic centers in amphidinin A (1), a cytotoxic linear polyketide isolated from a symbiotic marine dinoflagellate, Amphidinium sp., were elucidated to be 2R, 4R, 6S, 9R 11R, and 12S by the combination of J-based configuration analysis, modified Mosher's method, and density-functional theory calculations.
Takahiro, Iwai, Takaaki, Kubota, Jun'ichi, Kobayashi   +2 more
openaire   +2 more sources

The absolute configuration of (−)-corbasil

Tetrahedron, 1968
Abstract The absolute configuration of (−)-corbasil (III) [3-(3′,4′-dihydroxyphenyl)-3-hydroxy-2-amino-propane] is established by relating it stereochemically at the α-carbon atom to (+)-2-(3,4-dimethoxyphenyl)-isopropylamine (V) of known configuration,5 by a series of reactions not involving this asymmetric centre.
M T, Farrugia, G, Kirk
openaire   +2 more sources

The absolute configuration of physostigmine

Tetrahedron, 1969
Abstract Physostigmine, the toxic alkaloid of the Calabar bean, has been degraded systematically to (+)-1,3-dimethyl-3-ethyloxindole (Chart 1), which contains only one of the original asymmetric centers. The enantiomorph of this oxindole was then synthesized from (R)-(−)-2-methyl-2-phenylbutyric add, a substance of known configuration, allowing the ...
R K, Hill, G R, Newkome
openaire   +2 more sources

The absolute configuration of (−)-Aspidospermine

Experientia, 1968
Die absolute Konfiguration von (−)-Aspidospermin-N(b)-jodemthylat wurde rontgenographisch unter Anwendung der anomalen Streuung bestimmt. Dadurch ist die absolute Konfiguration von (−)-Aspidospermin festgelegt.
B M, Craven, D E, Zacharias
openaire   +2 more sources

Absolute Stereochemical Configuration of Morphine

Nature, 1952
THE morphine molecule contains five asymmetric carbon atoms and five interlocking ring systems, and constitutes a complicated three-dimensional structure the stereochemistry of which has recently attracted considerable interest. The initial suggestions of Schopf1 concerning the relative orientations at the asymmetric carbons 5, 9, 13 and 14 were ...
openaire   +2 more sources

Absolute configuration of fucoxanthin

Tetrahedron Letters, 1976
Abstract The common natural isomer of the allenic carotenoid fucoxanthin has the 3S,5R,6S,3′S,5′R,6′R configuration.
K. Bernard, G.P. Moss, Gy. Tóth, B.C.L. Weedon   +3 more
openaire   +1 more source