Circular Dichroism and Conformational Analysis of Diastereomeric Bicamphors

2000 ◽  
Vol 65 (4) ◽  
pp. 477-489 ◽  
Author(s):  
Stefan E. Boiadjiev ◽  
David A. Lightner
Keyword(s):  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Molecular Mechanics ◽  
Spectral Data ◽  
Relative Orientation ◽  
Nmr Analysis ◽  
Molecular Mechanics Calculations ◽  
H Nmr ◽  
The Third ◽  
Carbonyl Chromophores

Stereospecific syntheses afforded endo,endo- (1) and exo,exo- (2) bicamphors, while the third possible diastereomeric exo,endo-bicamphor (3) originated from nonselective camphor radical dimerization. The stereochemistry of bicamphor linkage was confirmed by 1H NMR analysis. Chiroptical and ultraviolet spectral data are presented for the three diastereomers 1-3 to show interchromophoric interaction. Conformational analysis to evaluate the relative orientation of each pair of carbonyl chromophores was accomplished by 1H NMR spectroscopy and molecular mechanics calculations.

Conformational analysis of [Cpp1, Sar7, Arg8] vasopressin by 1H-NMR spectroscopy and molecular mechanics calculations

2009 ◽  
Vol 38 (6) ◽  
pp. 528-538 ◽  
Author(s):  
MARK D. SHENDEROVICH ◽  
FRANCISZEK KASPRZYKOWSKI ◽  
ADAM LIWO ◽  
ILMARS SEKACIS ◽  
JURIS SAULITIS ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Molecular Mechanics ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Molecular Mechanics Calculations

Conformational Analysis of 2,4-Disubstituted 9-Oxobicyclo[3.3.1]nonane Derivatives

1995 ◽  
Vol 60 (2) ◽  
pp. 216-223
Author(s):  
Pelayo Camps ◽  
Joan Castañé ◽  
Carlos Jaime ◽  
Francesc Pérez ◽  
Santiago Vázquez
Keyword(s):  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Dicarboxylic Acid ◽  
Molecular Mechanics ◽  
Molecular Mechanics Calculations ◽  
C Nmr

The conformational analysis of several 2,4-disubstituted 9-oxobicyclo[3.3.1]nonane derivatives (diesters IIIb and IIIc, and dihalo compounds IV, Va, Vb and VI) derived from 9-oxobicyclo[3.3.1]nonane-exo-2, exo-4-dicarboxylic acid has been studied by 1H and 13C NMR spectroscopy with the aid of Molecular Mechanics Calculations (MM3 program).

Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives

1997 ◽  
Vol 62 (10) ◽  
pp. 1585-1598 ◽  
Author(s):  
Pelayo Camps ◽  
Diana Görbig ◽  
Victoria Muñoz-Torrero ◽  
Francesc Pérez
Keyword(s):  
Conformational Analysis ◽  
Molecular Mechanics ◽  
Related Compound ◽  
Methyl Derivative ◽  
Reaction Conditions ◽  
Molecular Mechanics Calculations ◽  
H Nmr ◽  
Nmr Data ◽  
Acid Catalyzed

(5α,9α,11β)-11-Hydroxy-6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulen-7-one ethylene ketal (6a) and its 11α-methyl derivative (6b) were prepared from monoketal 3. These compounds underwent acid-catalyzed transannular reactions leading to 6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulene derivatives 5a, 8a and 5b, 8b, respectively, depending on the reaction conditions. The compounds 6a and 6b were dehydrated to 6,7,8,9-tetrahydro-5H-5,9-prop[1]enobenzo[7]annulen-7-one (9a) and its 11-methyl derivative (9b), respectively. The conformational analysis of the 5,9-propanobenzo[7]annulene derivatives by molecular mechanics calculations (MM3 program) and the 1H NMR data show that hydroxyketal 6a and the related compound (5α,7β,9α)-6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulen-7-ol (4) exist mainly in the boat-chair conformation with the boat cycloheptenol ring, while for hydroxyketal 6b the chair-boat conformation (chair cycloheptenol ring) seems to be the preferred one.

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