Synthesis of new chiral crown ethers containing a (p-methoxyphenoxy)methyl moiety and their chiral recognition ability towards amino acid esters

Novel crown ethers 9–13 containing a chiral subunit derived from 3-(p-methoxyphenoxy)propane-1,2-diol 7 were prepared in enantiomerically pure forms. Chiral recognition properties of these receptors towards l- and d-amino acid derivatives were examined by the UV–vis titration method. These receptors exhibit good chiral recognition towards the isomers (up to KL/KD = 5.81, ΔΔG0 = 4.30 kJ mol−1) in CHCl3 at 25 °C.

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(S)-3-(p-Methoxyphenoxy)propane-1,2-diolC10H14O4[α]D20=+10.5 (c 0.5, MeOH)Source of chirality: (S)-glycidolAbsolute configuration: S

(S)-4-(p-Methoxyphenoxy)methyl-3,6-dioxa-1,8-octanediolC14H22O6[α]D24=+9.5 (c 0.25, MeOH)Source of chirality: (S)-3-(p-methoxyphenoxy)propane-1,2-diolAbsolute configuration: S

(S)-2-[(p-Methoxyphenoxy)methyl]-12-crown-4C16H24O6[α]D30=-9.5 (c 5, CHCl3)Source of chirality: (S)-3-(p-methoxyphenoxy)propane-1,2-diolAbsolute configuration: S

(S)-2-[(p-Methoxyphenoxy)methyl]-15-crown-5C18H28O7[α]D30=-14.5 (c 7, CHCl3)Source of chirality: (S)-3-(p-methoxyphenoxy)propane-1,2-diolAbsolute configuration: S

(S)-2-[(p-Methoxyphenoxy)methyl]-18-crown-6C20H32O8[α]D30=-8.8 (c 4.66, CHCl3)Source of chirality: (S)-4-(p-methoxyphenoxy)methyl-3,6-dioxa-1,8-octanediolAbsolute configuration: S

(S)-12-[(4-Methoxyphenoxy)methyl]-2,3-benzo-18-crown-6C24H32O8[α]D30=−2.70 (c 2, CHCl3)Source of chirality: (S)-4-(p-methoxyphenoxy)methyl-3,6-dioxa-1,8-octanediolAbsolute configuration: S

(S)-12-[(4-Methoxyphenoxy)methyl]-2,3-naphtho-18-crown-6C28H34O8[α]D30=-8.6 (c 3.76, CHCl3)Source of chirality: (S)-4-(p-methoxyphenoxy)methyl-3,6-dioxa-1,8-octanediolAbsolute configuration: S