Unveiling geometrical isomers and tautomers of isatin-hydrazones by NMR spectroscopy

MICHAELIS-ARBUSOV reaction of diastereoisomeric 2-methoxy-4-methyl-1,3,2-dioxaphosphorinans with benzyl halides is non-stereospecific. Cis- and trans-2-benzyl-2-oxo-4-methyl-1,3,2-dioxaphosphorinans were separated and analysed by means of IR, 31P and 13C NMR spectroscopy. 2-Benzyl-2-seleno-4-methyl-1,3,2-dioxaphosphorinans were synthesized and stereospecifically converted to 2-oxo-analogues. Stereochemistries are assigned to the geometrical isomers of all new compounds described in this paper. Application of direct spin-spin coupling constant values for structural elucidation is emphasized.

Download Full-text

Isolation and Structural Elucidation of Different Geometrical Isomers of Lycopene

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.77.6.369 ◽

2007 ◽

Vol 77 (6) ◽

pp. 369-375 ◽

Cited By ~ 53

Author(s):

Fröhlich ◽

Conrad ◽

Schmid ◽

Breithaupt ◽

Böhm

Keyword(s):

Nuclear Magnetic Resonance ◽

Double Bond ◽

Nmr Spectroscopy ◽

Physiological Role ◽

2D Nmr ◽

Biological Tissues ◽

Geometrical Isomers ◽

H Nmr ◽

Structure Activity ◽

Vis Spectroscopy

Five geometrical isomers of lycopene were isolated from a photoisomerized mixture on a semi-preparative C30 column and characterized by UV-vis spectroscopy, mass spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. 1H NMR and 2D NMR measurements were used to unambiguously assign the double bond configuration of five isomers: (5Z,9’Z)-, (9Z)-, (5Z,9Z)-, (all-E)-, and (5Z)-lycopene. This will allow other laboratories to use the results for their C30 HPLC. In addition, it is possible to investigate structure-activity relationships for these lycopene isomers which will improve the understanding of their physiological role in biological tissues.

Download Full-text

Synthesis of [RuCl2(dppb)(PPh3)] and Identification of the cis- and trans-[RuCl2(dppb)(phen)] Geometrical Isomers via 31P{1H} NMR Spectroscopy. An Undergraduate Experiment for Inorganic Chemistry

Journal of Chemical Education ◽

10.1021/ed078p87 ◽

2001 ◽

Vol 78 (1) ◽

pp. 87 ◽

Cited By ~ 13

Author(s):

Salete L. Queiroz ◽

Márcio P. de Araujo ◽

Alzir A. Batista ◽

Kenneth S. MacFarlane ◽

Brian R. James

Keyword(s):

Inorganic Chemistry ◽

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Geometrical Isomers ◽

Cis And Trans

Download Full-text

Synthesis and Conformational Assignment of N-(E)-Stilbenyloxymethylenecarbonyl-Substituted Hydrazones of Acetone ando-(m- andp-) Chloro- (nitro-) benzaldehydes by Means of and NMR Spectroscopy

Journal of Spectroscopy ◽

10.1155/2013/197475 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Przemysław Patorski ◽

Elżbieta Wyrzykiewicz ◽

Grażyna Bartkowiak

Keyword(s):

Nmr Spectroscopy ◽

Spectral Data ◽

Energy Barriers ◽

Geometrical Isomers ◽

Nmr Techniques ◽

Supporting Material ◽

Amide Conformers

Eighteen new N-(E)-stilbenyloxyalkylcarbonyl-substituted hydrazones ofortho- (meta- andpara-) chloro- (nitro-) benzaldehydes1–18and two analogous hydrazones of acetone19-20were prepared. The stereochemical behavior of1–18in dimethyl-d6sulfoxide solution has been studied by NMR and NMR techniques, using spectral data of19and20as supporting material. The E-geometrical isomers and cis-/trans-amide conformers have been found for these hydrazones. Energy barriers of isomers are reported.

Download Full-text