Purification of a Water-Sensitive Natural Product with an Aprotic CPC Solvent System

Abstract
The partition coefficients of arachidonic acid (AA), prostaglandin (PG) H2 and PGE2 in the binary acetonitrile-hexane two-phase solvent system can be favorably modified by addition of diethyl ether. In the ternary two-phase solvent system acetonitrile-hexane-diethyl ether the partition coefficients of AA and the prostaglandins diverge as the ratio of ether to acetonitrile-hexane (1:1) is increased from 0.00 to 0.15 while the partition coefficients of PGH2 and PGE2 diverge as the ratio of ether to acetonitrile-hexane (1:1) is increased from 0.15 to 0.30. Isolation by CPC of PGH2 from the AA bioconversion reaction mixture is described.