Synthesis of Enantiopure Chiral Perhydrobenzimidazole and Hexahydroquinoxaline Derivatives
作者:Barbara Zaleska、Robert Socha
DOI:10.1007/s007060070038
日期:2000.10.16
Starting from 2-anilino-2-ethoxy-3-oxothiobutyric acid anilides and (R,R)-or (S,S)-trans-1,2-diaminocyclohexane, chiral C2-disubstituted perhydrobenzimidazole and trans-4a,5,6,7,8,8a-hexahydroquinoxaline derivatives were obtained depending on the polarity of the solvent.
Barnikov, G.; Kunzek, H., Liebigs Annalen der Chemie, 1966, vol. 700, p. 36 - 45
作者:Barnikov, G.、Kunzek, H.
DOI:——
日期:——
Reaction of 3-oxo-3-R1-N-R2-propanethioamides with 2-amino-5-R-pyridines
作者:V. N. Britsun、A. N. Borisevich、V. B. Pirozhenko、M. O. Lozinskii
DOI:10.1134/s1070428007020200
日期:2007.2
Direction of a reaction between 3-oxo-3-R-1-N-R-2-propanethioamides and 2-amino-5-R-pyridines in acetic acid depends on the structure of initial thioamides: at R-1 = Me, R-2 =Ar, Et 2-methyl-7-R-4H-pyrido[1,2-a]-pyrimidine-4-thiones are obtained, and at R-1 = Ar, R-2 = Me form 1-methyl-5-(N-methylaminothiocarbonyl)-4,6diaryl- 1,2-dihydropyridine-2-thiones.
Spectroscopic Study of the Conformation of 2-Anilino-2-ethoxy-3-oxothiobutyric Acid Anilides
An NMR study of the equilibrium mixture of two conformers of 2-anilino-2-ethoxy-3-oxothiobutyric acid anilides 3 allows to estimate their population ratio in solvents of increasing polarity. X-Ray analysis as well as IR spectroscopy confirmed that the conformer present in the solid state is stabilized by two hydrogen bonds. The structural basis of the second conformer observed in solution is the 1,4-type S...O interaction between the sulfur of the thioanilide moiety and the oxygen of the ethoxy group with a distance of 2.878 Angstrom.