In chemistry, a thioketal is the sulfur analogue of a ketal, with one of the oxygen replaced by sulfur. A dithioketal has both oxygens replaced by sulfur. In chemistry, a thioketal is the sulfur analogue of a ketal, with one of the oxygen replaced by sulfur. A dithioketal has both oxygens replaced by sulfur. Thioketals can be obtained by reacting ketones or aldehydes with thiols. Ketones can be reduced at neutral pH using the thioketal method. The thioketal prepared from the ketone can be easily reduced by catalytic hydrogenation using Raney nickel in a reaction known as the Mozingo reduction.