Absolute Stereochemistry and CD Spectra of Resolved Enantiomers of the Colored Form of a Photochromic Dithienylethene

1998 ◽  
Vol 27 (11) ◽  
pp. 1093-1094 ◽  
Author(s):  
Yasushi Yokoyama ◽  
Naoya Hosoda ◽  
Yasuko T. Osano ◽  
Chizuko Sasaki
Keyword(s):  
Colored Form ◽  
Cd Spectra ◽  
Absolute Stereochemistry

Sterically Crowded Heterocycles. XIII. An Insight Into the Absolute Stereochemistry of Atropisomeric (Z)-3-(Imidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ones

2000 ◽  
Vol 65 (10) ◽  
pp. 1643-1652
Author(s):  
Radek Pohl ◽  
Jan Sýkora ◽  
Petr Maloň ◽  
Stanislav Böhm ◽  
Bohumil Kratochvíl ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Heats Of Formation ◽  
Cd Spectra ◽  
X Ray ◽  
Space Analysis ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Insight Into

The absolute configuration of the atropisomeric (Z)-3-(5-methyl-2-phenylimidazo[1,2-a]pyridin-3-yl)-1,3-diphenylprop-2-en-1-one was evaluated to be R for the dextrorotatory and S for the laevorotatory enantiomers. The assignment is based on their two-step syntheses via atropodiastereoisomeric carbamates prepared from the corresponding atropodiastereoisomeric alcohols with (R)-(+)-α-phenylethyl isocyanate and by a complete X-ray space analysis of the quaternary triiodide obtained from the (R)-(+)-enantiomer. CD spectra and PM3 calculated heats of formation for selected compounds are discussed in relation to the found molecular configurations.

scholarly journals Antimicrobial and Antiparasitic Abietane Diterpenoids from the Roots of Clerodendrum eriophyllum

2010 ◽  
Vol 5 (6) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Francis Machumi ◽  
Volodymyr Samoylenko ◽  
Abiy Yenesew ◽  
Solomon Derese ◽  
Jacob O. Midiwo ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Antimalarial Activity ◽  
Antibacterial Activities ◽  
Cd Spectra ◽  
Normal Series ◽  
Abietane Diterpenoids ◽  
Abietane Diterpenes ◽  
First Time ◽  
Absolute Stereochemistry

Chromatographic separation of the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum, led to the isolation of ten abietane diterpenoids (1-10), one of which (1) was isolated for the first time from a natural source. Using spectroscopic data, the structure of 1 was determined to be 12-hydroxy-8,12-abietadiene-3,11,14-trione. Circular dichroism (CD) spectra showed that the stereochemistry of compounds 1, 3, and 6-8 belongs to the normal series of abietane diterpenes, which confirmed the absolute stereochemistry of the isolated compounds. Compounds 1-10 were evaluated for their in vitro antiplasmodial, antileishmanial, antifungal and antibacterial activities. Compounds 3 and 7 exhibited potent antifungal activity (IC50/MIC 0.58/1.25 and 0.96/2.5 μg/mL, respectively) against C. neoformans, whereas 3, 6 and 7 showed strong antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus with IC50/MIC values between 1.33-1.75/2.5-5 and 0.96-1.56/2.5 μg/mL, respectively. In addition, compounds 3 and 9 exhibited potent antileishmanial activity (IC50 0.08 and 0.20 μg/mL, respectively) against L. donovani, while 3 and 7 displayed weak antimalarial activity against Plasmodium falciparum, but 9 was inactive.

Sign in / Sign up

Export Citation Format

Share Document