51373-14-9Relevant academic research and scientific papers
Optically Active Amines. 36. Application of the Benzene Chirality Rule to Ring-Substituted Mandelic Acids
Colon, Diana F.,Pickard, Simeon T.,Smith, Howard E.
, p. 2322 - 2326 (1991)
The positive sign of the 1Lb Cotton effects (CEs) from about 250 to 270 nm in the circular dichroism (CD) spectrum of (R)-mandelic acid and its sodium salt is determined by vibronic borrowing from allowed transitions at shorter wavelength.On ring substitution, transition moments are induced in the benzene ring bonds adjacent to the attachment bond of the chiral group, resulting in enhanced coupling of the 1Lb transition with the chiral group.The sign of the 1Lb CEs for a ring-substituted (R)-mandelic acid may be the same or opposite to that of (R)-mandelic acid, but the sign of its 1Lb CEs can often be correlated wit h its absolute configuration provided the ring position of the substituent and its spectroscopic moment is taken into account.
Hydrogen-bonding sheets in crystals for chirality recognition: synthesis and application of (2S,3S)-2,3-dihydroxy- and (2S,3S)-2,3-dibenzyloxy-1,4-bis(hydroxyamino)butanes
Kobayashi, Yuka,Kokubo, Yasushi,Aisaka, Takamitsu,Saigo, Kazuhiko
scheme or table, p. 2536 - 2541 (2009/04/11)
Two enantiopure bis(hydroxyamino) compounds were successfully prepared from dialkyl tartrate by a chiral-pool method and applied as basic resolving agents in the enantioseparation of 2-arylpropanoic acids and arylglycolic acids. (2S,3S)-2,3-Dihydroxy-1,4-bis(hydroxyamino)butane (2S,3S)-1a could moderately recognize the chirality of the 2-arylpropanoic acids, while (2S,3S)-2,3-dibenzyloxy-1,4-bis(hydroxyamino)butane (2S,3S)-1b could not due to the low crystallinity of both the corresponding diastereomeric salts. On the other hand, (2S,3S)-1b showed a similar chirality-recognition ability for the arylglycolic acids. The ability of (2S,3S)-1b was different from those generally observed for widely used primary amine-type resolving agents with regard to the relationship between the resolution efficiency and the similarity in the relative molecular length of a resolving agent and a target racemate. The X-ray crystallographic analyses of the less-soluble diastereomeric salts revealed that in the salts (2S,3S)-1a formed a supramolecular sheet, of which the distance was variable to make the resultant dissymmetric space fit to the shape of the target acids, and that (2S,3S)-1b was constructed from a robust supramolecular sheet, consisting of hydrogen-bonding 21 columns, with the participation of the hydroxy group of the arylglycolic acids. These X-ray crystallographic analyses also suggested that for the formation of a supramolecular sheet, the coexistence of two hydroxyamino groups is essential.
