Synthesis and enantiomeric recognition studies of dialkyl-substituted 18-crown-6 ethers containing an acridine fluorophore unit

Selectivity of the reported dimethyl-substituted (R,R)-1, the diisobutyl-substituted (R,R)-2 acridino-18-crown-6 ethers and the newly synthesized acridino-crown ether (S,S)-3 containing the methyl groups one carbon–carbon bond further away from the acridine unit was studied towards the enantiomers of the hydrogen perchlorate salts of α-phenylethylamine, α-(1-naphthyl)ethylamine, phenylglycine methyl ester and phenylalanine methyl ester using fluorescence.

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(8S,16S)-8,16-Dimethyl-6,9,12,15,18-pentaoxa-25-azatetracyclo[21.3.1.05,26.019,24]heptacosa-1(26),2,4,19,21,23(27),24-heptaeneC23H27NO5Ee >97%[α]D25=+7.7 (c 0.36, CH2Cl2)Source of chirality: ethyl (2S)-(−)-2-hydroxypropanoateAbsolute configuration: (8S,16S)

(2S,2′S)-2,2′-Oxybis[(ethane-2,1-diyloxy)propane-2,1-diyl] bis(4-methylbenzenesulfonate)C24H34O9S2Ee >97%[α]D23=-6.7 (c 1.2, CH2Cl2)Source of chirality: ethyl (2S)-(−)-2-hydroxypropanoateAbsolute configuration: (2S,2′S)

(8S,16S)-8,16-Dimethyl-6,9,12,15,18-pentaoxa-25-azatetracyclo[21.3.1.05,26.019,24]heptacosa-1(26),2,4,19,21,23-hexaene-27-oneC23H27NO6Ee >97%[α]D19=+54.2 (c 0.25, CH2Cl2)Source of chirality: ethyl (2S)-(−)-2-hydroxypropanoateAbsolute configuration: (8S,16S)