<p>Disclosed is a process for preparing an hydroxysulfone of formula (viii) comprising oxidation of a hydroxysulfonamide of formula (vii) in the presence of an oxidizing agent. Also disclosed is a process for preparing an acetoamidosulfone of formula (ix-a) comprising preparing a hydroxysulfone of formula (viii) and converting the hydroxysulfone of formula (viii) to the acetoamidosulfone of formula (ix-a) in the presence of acetonitrile and an acid. A process for preparing dorzolamide of formula (x) is also disclosed. The process comprises preparing an acetoamidosulfone of formula (ix-a) followed by reducing the acetoamidosulfone of formula (ix-a) using a suitable reducing agent.</p>
