| 摘要 |
An improved process for the preparation in high yields of a compound of the formula <IMAGE> I wherein R is an optionally substituted phenyl group, Y is selected from the group consisting of Me and a hydrocarbon, Me is a metal cation and E is selected from the group consisting of hydrogen and a metal cation comprising reacting a compound of the formula <IMAGE> II wherein Q is selected from the group consisting of hydrogen and a silyl protecting group, Rz is an optionally substituted phenyl with the proviso that any hydroxy group present on the phenyl are replaced by -OQz, wherein Qz is a silyl protecting group and Ez is a carboxyl protecting group, with a compound of the formula <IMAGE> III wherein Z is a halogen and X is selected from the group consisting of OY and Z at low temperatures under anhydrous conditions and carefully hydrolyzing the resulting product either with just enough water to remove protecting groups and hydrolyze the Z groups to hydroxy groups and, still under anhydrous conditions, reacting the compound obtained with an organic metal salt carrying a metal cation Me or, in the case wherein the organic solvent is water-insoluble, with an excess of water, followed by washing the mixture with water acidified to a pH of 0 to 3, extracting the organic phase with neutral water and forming a salt with a hydroxide or a salt carrying a salt-forming cation Me.
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