A solution of sodium metaperiodate (0.026 g.) in water (2 ml.) was added to a stirred solution of (1RS, 2RS)-1-(9-n-heptylthiononyl)-2-p-hydroxyphenyl-1,2,3,4-tetrahydronaphth-6-ol (Example 7; 0.052 g.) in methanol (20 ml.) and the mixture was stirred for 16 hours. The methanol was removed by evaporation, the residue was extracted three times with ethyl acetate (10 ml. each time) and the combined extracts were washed with water, dried and evaporated to dryness. The residue was purified by chromatography on a silica gel column using a 2:1 v/v mixture of toluene and ethyl acetate as eluant, and there was thus obtained as an oil (1RS, 2RS)-1-(9-n-heptylsulphinylnonyl)-2-p-hydroxyphenyl-1,2,3,4-tetrahydronaphth-6-ol, the structure of which was confirmed by proton magnetic resonance and mass spectroscopy.
