RECOGNITION BY NEW SYMMETRICALLY SUBSTITUTED CHIRAL DIPHENYL-BUTYLPYRIDINO-18-CROWN-6 AND DI-TERT-BUTYLPYRIDINO-18-CROWN-6 AND ASYMMETRICALLY SUBSTITUTED CHIRAL DIMETHYLPYRIDINO-18-CROWN-6 LIGANDS OF THE ENANTIOMERS OF VARIOUS ORGANIC AMMONIUM PERCHLORATES

被引:111
作者
HUSZTHY, P
BRADSHAW, JS
ZHU, CY
IZATT, RM
LIFSON, S
机构
[1] BRIGHAM YOUNG UNIV,DEPT CHEM,PROVO,UT 84602
[2] WEIZMANN INST SCI,DEPT CHEM PHYS,IL-76100 REHOVOT,ISRAEL
[3] TECH UNIV BUDAPEST,INST ORGAN CHEM,H-1521 BUDAPEST,HUNGARY
关键词
D O I
10.1021/jo00010a028
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Three new chiral pyridino-18-crown-6 ligands have been prepared. These ligands contain either two phenyl, two tert-butyl, or two methyl substituents on chiral macroring carbon atoms. The chiral di-tert-butyl-substituted diester crown analogue was also prepared. The starting chiral di-tert-butyl-substituted tetraethylene glycol needed to prepare the two di-tert-butyl-substituted crowns was obtained from chiral tert-butyl-1,2-ethanediol, which was resolved from its bis(hydrogen phthalate) brucine salt. A high degree of chiral recognition in CD2Cl2 of the enantiomers of [alpha-(1-naphthyl)ethyl]ammonium perchlorate (NapEt) was shown by the diphenyl- and di-tert-butyl-substituted crowns as measured by differences in the free energy of activation (DELTA-G(c) double-ended-dagger) values determined by temperature-dependent H-1 NMR spectroscopy. The diphenyl- and di-tert-butyl-substituted crowns also exhibited high chiral recognition for the enantiomers of NapEt and other chiral organic ammonium salts in methanol and methanol-chloroform mixtures as shown by a large difference in the log K values determined by a direct H-1 NMR technique.
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页码:3330 / 3336
页数:7
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