Abstract Oxidation with ozone of 3, 7-dimethyloctyl acetate (7) adsorbed on silica gel, alumina or barium sulphate proceeds in good yield and affords mainly the 7-hydroxy compound (8) and the 7-nor-ketone (9). Minor products include the 3-alcohol (10) and the 3, 7-diol (11). The reaction involves interaction of gaseous ozone with the adsorbed organic substrate. The relative yields of the various products are related to the substrate loading. ...