PURPOSE: To separate the pure cis-syn-cis isomer of a crown ether in high yield, by dissolving a mixture of the isomers of the crown ether in an organic solvent, adding uranyl nitrate to the solution and separating the formed precipitate remaining in the solution.
CONSTITUTION: A mixture of the isomers of a compound of the formula [(n) is 0-3; R1 and R2 are each an alkyl, a alkoxyalkyl or a poly(alkoxyalkyl), or together form a cycloalkyl ring] containing cis-syn-cis isomer (A) and cis-anti-cis isomer (B) is dissolved in an organic solvent, preferably a saturated aliphatic or aromatic hydrocarbon, especially heptane. Uranyl nitrate is added to the solution to precipitate the isomers in the form of complexes with the uranyl nitrate except the isomer (A). After removal of the precipitate, the isomer (A) is recovered from the solution. Also, the isomer (B) is recovered in the pure form from the precipitate. Prior to the separation, it is preferred to crystallize the isomer (B) from the solution and separate the crystalline isomer (B), thereby to make a concentrated mixture of the isomer (A).
GIYU AREN
FUOO JIYATSUKU
GIYUON BUANSAN
SHIYOMERU RODORUFU
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