Enantiomerically pure chiral phenazino-crown ethers: synthesis, preliminary circular dichroism spectroscopic studies and complexes with the enantiomers of 1-arethyl ammonium salts
E. Samu et al., Enantiomerically pure chiral phenazino-crown ethers: synthesis, preliminary circular dichroism spectroscopic studies and complexes with the enantiomers of 1-arethyl ammonium salts, TETRAHEDR-A, 10(14), 1999, pp. 2775-2795
Enantiomerically pure chiral crown ethers containing the phenazine unit [(R
,R)-2(S,S)-8] were prepared by two types of cyclization reactions. Ligands
(R,R)-2, (R,R)-3, (S,S)-4, (R,R)-5, (R,R)-6 and (R,R)-7 were prepared from
phenazine-1,9-diol 9 and the appropriate ditosylates (S,S)-10-(S,S)-15 in w
eak basic conditions with complete inversion of configuration. Ligands (S,S
)-2, (S,S)-7 and (S,S)-8, however, were prepared from 1,9-dichlorophenazine
19 and the appropriate diols (S,S)-16(S,S)-18 in strong basic conditions w
ith retention of configuration. Enantiomeric recognition of most of the chi
ral ligands with alpha-(1-naphthyl)ethylammonium perchlorate (NEA) and alph
a-phenylethylammonium perchlorate (PEA) has been studied by CD spectroscopy
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