Thioketal

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General chemical structure of a dithioketal

In

ketal (R2C(OR)2), with one of the oxygen replaced by sulfur (as implied by the thio-
prefix), giving the structure R2C(SR)OR. A dithioketal has both oxygens replaced by sulfur (R2C(SR)2).

Thioketals can be obtained by reacting

thiols
(−SH).

An oxidative cleavage mechanism has been proposed for dithioketals, which involves thioether oxidation, the formation of thionoiums, and hydrolysis, resulting in the formation of aldehyde and ketone products.[1]

Thioketal moieties are found to be responsive to reactive oxygen species (ROS).[1] In the presence of ROS, thioketals can be selectively cleaved.[2] ROS successfully cleave heterobifunctional thioketal linkers, which have been found to have therapeutic potential, as they can produce ROS-responsive agents with two different functionalities.[2]

Ketones can be reduced at neutral pH via conversion to thioketals; the thioketal prepared from the ketone can be easily reduced by catalytic hydrogenation using Raney nickel in a reaction known as the Mozingo reduction.

See also

References