A 1305 (OTTO) Acetyl acetone, 99% Cas no 123-54-6 - used in the synthesis of pharmacy and intermediates. A 1305 (OTTO) Acetyl acetone, 98% Cas no 123-54-6 - used as the solvents for cellulose acetate, the drying agent for paints and varnishes, etc., and are also important analytical reagents.