ISSN:
0899-0042
Keywords:
helicity
;
steric shielding
;
polychlorinated
;
ChiralPak OT(+)
;
poly(triphenylmethyl methacrylate)
;
enantiomerization barrier
;
racemization kinetics
;
circular dichroism
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The perchlorotriphenylmethyl radical (PTM) shows enantiomerism due to restricted internal rotations. Several chiral stationary phases have been tested in different conditions for the resolution of PTM by HPLC. Only poly(triphenylmethyl methacrylate) provided sufficient resolution for carrying out a micropreparative scale separation. Racemization of (+)- and (-)-PTM was monitored polarimetrically as a function of time. The process was found to follow strict first-order kinetics. The value of ΔG#303.8 = 23.6 Kcal · mol-1 agrees with that determined previously by HPLC with the stopped flux technique (Crespo, Doctoral Thesis, CETS Institut Químic de Sarrià, 1991). Following the helicity rules in the circular dichroism spectrum, (+)-PTM can be assumed to have (P) configuration and (-)-PTM (M) configuration. © 1995 Wiley-Liss, Inc.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chir.530070308
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