Nine sesquiterpenoid dimers with four unprecedented types of carbon skeletons from Chloranthus henryi var. hupehensis

2021 ◽  
Author(s):  
Danyang Zhang ◽  
Xiao-Xia Wang ◽  
Ya-Nan Wang ◽  
Min Wang ◽  
Peng-Yu Zhuang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Circular Dichroism ◽  
Magnetic Resonance ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Electronic Circular Dichroism ◽  
X Ray ◽  
Circular Dichroïsm ◽  
Nuclear Magnetic

Chlorahupetones A-I (1−9), nine sesquiterpenoid dimers, were isolated from Chloranthus henryi var. hupehensis. Their structures were characterized by nuclear magnetic resonance (NMR), electronic circular dichroism (ECD), and X-ray diffraction analysis....

Tautomerism of bis(2-benzothiazolyl)methanes

1988 ◽  
Vol 66 (6) ◽  
pp. 1467-1473 ◽  
Author(s):  
Carmen Avendaño ◽  
María Teresa Ramos ◽  
José Elguero ◽  
María Luisa Jimeno ◽  
Juana Bellanato ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Methyl Derivative ◽  
Model Compounds ◽  
X Ray ◽  
Nuclear Magnetic

Tautomerism of dibenzothiazolylmethane (1) and its C-methyl derivative (2) has been studied by 1H nuclear magnetic resonance, ultraviolet, and infrared spectroscopy using C,C-dimethyl (3) and N-methyl (4) derivatives as model compounds of the "CH" and "NH" forms, respectively. X-ray diffraction analysis of the "fixed" N-methyl derivative 4 shows that it corresponds to the Z-sE isomer 4b2. The CH tautomers are unstable in solution and they slowly isomerize into a mixture of NH tautomers that depends on the solvent and on the C-substituent (H or CH3).

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