SYNTHESIS FROM ARACHIDONIC-ACID OF POTENTIAL PROSTAGLANDIN PRECURSORS

Arachidonic acid has been converted by aerobic oxidation with lipoxygenase (ex soybean) as catalyst and in the presence of sodium borohydride in a one-pot procedure (1 g scale) into (5Z,8Z,11Z,13E)(15S)-15-hydroxyeicosa-5,8,11,13- tetraenoic acid. The methyl (15S)-15-hydroxyeicosatetraenoate or its p-nitrobenzoate derivative may be epoxidised with m-chloroperbenzoic acid to afford mixtures of the 5,6-, 8,9-, 11,12-, and 13,14-monoepoxides together with a mixture of bisepoxides. The methyl (15S)-15-(p-nitrobenzoyloxy) eicosatetraenoate epoxides can be separated by preparative t.l.c. The methyl (15S)-15-(mercaptoacetoxy)eicosatetraenoate has been prepared from the chloroacetate derivative of the methyl (15S)-15-hydroxyeicosatetraenoate by reaction with potassium thioacetate followed by selective hydrolysis of the thioester function.