Structural studies of organosulfur compounds. 2. Conformational analysis of 2-methoxy-trans-hexahydro-1,4-benzoxathianes

1977 ◽  
Vol 42 (3) ◽  
pp. 438-441 ◽  
Author(s):  
Slayton A. Evans ◽  
Barry Goldsmith ◽  
Robert L. Merrill ◽  
Robert E. Williams
Keyword(s):  
Conformational Analysis ◽  
Organosulfur Compounds ◽  
Structural Studies

13C-13C spin-spin coupling constants in structural studies: XL. Conformational analysis of N-vinylpyrroles

2007 ◽  
Vol 43 (6) ◽  
pp. 880-887 ◽  
Author(s):  
Yu. Yu. Rusakov ◽  
L. B. Krivdin ◽  
E. Yu. Shmidt ◽  
A. M. Vasil’tsov ◽  
A. I. Mikhaleva ◽  
...  
Keyword(s):  
Conformational Analysis ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Structural Studies ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Structural studies of organosulfur compounds. 3. Stereochemistry and conformational distortions in trans-hexahydro-1,4-benzoxathiane S-oxides

1977 ◽  
Vol 42 (13) ◽  
pp. 2206-2211 ◽  
Author(s):  
Donna M. Frieze ◽  
Philip F. Hughes ◽  
Robert L. Merrill ◽  
Slayton A. Evans
Keyword(s):  
Organosulfur Compounds ◽  
Structural Studies ◽  
In Trans

Multidimensional conformational analysis of allyl methyl disulfide: a key component of garlic

2000 ◽  
Vol 78 (3) ◽  
pp. 362-382 ◽  
Author(s):  
Alvin C Lin ◽  
Salvatore J Salpietro ◽  
Eugen Deretey ◽  
Imre G Csizmadia
Keyword(s):  
Potential Energy ◽  
Conformational Analysis ◽  
Ab Initio ◽  
Lipid Lowering ◽  
Torsional Angle ◽  
Organosulfur Compounds ◽  
Cholesterol Lowering ◽  
Torsional Angles ◽  
Activity Mechanism ◽  
Molecular Computations

Organosulfur compounds in garlic, like allyl methyl disulfide, have been found to be involved in antimutagenic, anticarcinogenic, antithrombotic, and lipid-lowering activities, and it has also been found to act as an antioxidant. Ab initio molecular computations were performed on dihydrogen disulfide (1) with respect to torsional angle τ1 = τ(H·S-S·H), hydrogen methyl disulfide (2) with respect to torsional angle τ1 = τ(H·S-S·CH3), and allyl methyl disulfide (3) with respect to torsional angles τ1 = τ(H3C2·CH2·S-S·CH3), τ2 = τ(H3C2·CH2-S·S·CH3), and τ3 = τ(H3C2-CH2·S·S·CH3). Potential energy curves (PEC) were obtained from 1 and 2, i.e., E = E(τ1), from which optimized structures were obtained at the HF/6-31G* level of theory. These optimized structures were used to investigate the potential energy hypersurface surface (PEHS) of 3, i.e., E = E(τ1,τ2,τ3). One-dimensional scans along τ2 and τ3 (where τ1 = ±90°; τ1 = 180°) were performed at the HF/3-21G* level of theory. From these scans, six lower energy pairs of enantiomeric minima (i.e., [g+g+g+| g-g-g-], [g+ag- | g-ag+], [g+g-g+ | g-g+g-], [g+g+g-| g-g-g+], [g+ag- | g-ag+], and [g+g-g-| g-g+g+]) as well as 3 higher energy minima (i.e., [g+g+s | g-g-s], [g+as | g-as], and [g+g-s | g-g+s]) were optimized at τ1 = ±90° at the HF/6-31G* and B3LYP/6-31G* levels of theory. The global minimum was determined to be the [g+g-g+ | g-g+g-] enantiomeric pair of conformers, and the fully symmetrical anti-anti-anti [a a a] structure was determined to be a second-order saddle point on the PEHS of 3. Although there are no stereocentres in 3, there is chirality in the conformational twist with respect to the [a a a] conformation through τ1 = τ2 = τ3 = 180°. Based on the energies and MO diagrams of the HUMO and LUMO +1 of 3, the anticarcinogenic and cholesterol lowering activity mechanism of 3 is presented.Key words: ab initio MO computations, allyl methyl disulfide, multidimensional conformational analysis (MDCA), anticarcinogenic, cholesterol lowering.

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