Cyclodextrin derivatives in gas chromatographic separation of racemates with different volatility. Part XV: 6-O-t-butyldimethylsilyl- versus 6-O-t-hexyldimethylsilyl-beta and -gamma derivatives
C. Bicchi et al., Cyclodextrin derivatives in gas chromatographic separation of racemates with different volatility. Part XV: 6-O-t-butyldimethylsilyl- versus 6-O-t-hexyldimethylsilyl-beta and -gamma derivatives, J MICROCOL, 11(7), 1999, pp. 487-500
The 2,3-di-O-methyl-, 2,3-di-O-ethyl-, and 2,3-di-O-acetyl- derivatives of
6-t-hexyldimethylsilyl-beta- and -gamma-cyclodextrins (THDMS-beta- and -gam
ma-CDs) were synthesized. The performance of columns prepared with these CD
derivatives diluted in polysiloxanes with different polarity (PS-347.5, PS
-086, and OV-1701) was evaluated with several series of racemates having di
fferent structures and volatilities. The results obtained with THDMS-beta-
and -gamma-CDs were compared with those of the corresponding 6-O-t-butyldim
ethylsilyl-beta- and -gamma derivatives (TBDMS-beta- and -gamma-CDs) to eva
luate the influence on enantioselectivity of the substituent in position 6
of the sugar units of the two cyclodextrins. Columns prepared with both ser
ies of derivatives (THDMS- and TBDMS-beta- and -gamma-CDs) were evaluated b
y analyzing a series of high-to-medium volatility racemates and of medium-t
o-low volatility chiral pesticides. For high-to-medium volatility racemates
, the TBDMS-beta-CDs are the most enantioselective, while for medium-to-low
volatility racemates the THDMS-gamma-CDs have a better enantioselectivity
than the corresponding TBDMS-beta-CDs, (C) 1999 John Wiley & Sons, Inc.