Comparative Conformational Study of a New Terpenoid-like Chalcone

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.

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Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851899 ◽

1985 ◽

Vol 50 (8) ◽

pp. 1899-1905 ◽

Cited By ~ 4

Author(s):

Milena Masojídková ◽

Jaroslav Zajíček ◽

Miloš Buděšínský ◽

Ivan Rosenberg ◽

Antonín Holý

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Conformational Study ◽

H Nmr ◽

Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

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Synthesis and conformational investigation of β-turn forming tetra- and hexapeptides

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19821884 ◽

1982 ◽

Vol 47 (7) ◽

pp. 1884-1892

Author(s):

A. N. Abdel Rahman ◽

S. Abdel Rahman

Keyword(s):

Energy Transfer ◽

Phase Method ◽

Conformational Study ◽

Poly Ethylene Glycol ◽

High Solubility ◽

Liquid Phase Method ◽

Conformational Investigation ◽

Transfer Method ◽

Poly Ethylene ◽

Good Agreement

Tetra- and hexapeptides containing Pro-Gly or Gly-Pro or Aib-Pro in their sequences were synthesized using the liquid-phase method. The high solubility of the poly(ethylene glycol) bound peptides in water and in organic solvents enables the application of the singlet-singlet energy transfer method for conformational investigation of these peptides. The conformational study in solid state by IR and in solution by CD were carried out in parallel to the energy transfer method. The qualitative results generated by IR and CD were found to be in good agreement with the quantitative end-to-end distances given by the energy transfer method.

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Configurational Assignment and Conformational Study of Methylglyoxal Bisdimethylhydrazones Derived from the 2-Ethoxypropenal Precursor

Australian Journal of Chemistry ◽

10.1071/ch05309 ◽

2006 ◽

Vol 59 (3) ◽

pp. 211 ◽

Cited By ~ 14

Author(s):

Leonid B. Krivdin ◽

Lyudmila I. Larina ◽

Kirill A. Chernyshev ◽

Natalia A. Keiko

Keyword(s):

Ab Initio Calculations ◽

Ab Initio ◽

Experimental Measurements ◽

Conformational Study ◽

Lone Pairs ◽

Configurational Assignment ◽

Out Of Plane ◽

High Level

A configurational assignment of the isomeric methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor has been performed based on experimental measurements and high-level ab initio calculations of 1J(C,C) and 1J(C,H) couplings. The results reveal the marked stereochemical dependence upon the orientation of the lone pairs of both nitrogen atoms in different isomers. Methylglyoxal bisdimethylhydrazone is shown to exist in a mixture of the EE and ZE isomers (ca. 75:25), both of which adopt predominant s-trans conformations with minor (up to 8°) out-of-plane deviations.

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