Chiral isothiocyanates – An approach to determination of the absolute configuration using circular dichroism measurement
Oskar Michalski , Dariusz Cież
AbstractChiral alkyl 2-isothiocyanates have been obtained from enantiopure, aliphatic amines. ECD measurements allowed us to correlate an absolute configuration at C-2 with a sign of the Cotton effect (CE) observed for n–π* transition at the longer-wavelength range of the spectrum. Chirooptical data calculated for all enantiomers were consistent with the measured CE values and indicated that the weak absorption band at 240 nm could give an important information concerning the stereochemistry of simple, chiral isothiocyanates. Optically active esters of 2-isothiocyanatocarboxylic acids, prepared from α-amino acids, showed two absorption bands located over 195 nm. The more intensive band near 200 nm and the weak absorption located at 250 nm were related to n–π* transitions in NCS group. TD DFT calculations carried out for methyl esters of 2-isothiocyanatocarboxylic acids showed the correlation between signs of CE determined for both absorption bands, and the absolute configuration on C-2.
|Journal series||Journal of Molecular Structure, ISSN 0022-2860, (A 20 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||Isothiocyanates, Absolute configuration, Cotton effect, CD spectroscopy, TD DFT calculations|
|ASJC Classification||; ; ;|
|Publication indicators||= 3; : 2013 = 0.843; : 2013 = 1.599 (2) - 2013=1.585 (5)|
|Finansowanie||MNiSW - grant nr N N204 310037|
|Finansowanie||Program Operacyjny Innowacyjna Gospodarka (POIG) - kontrakt nr POIG.02.01.00-12-023/08|
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