A steroid having the formula ##STR1## or the 1,2-dehydro derivative thereof, can be prepared by reacting the corresponding steroid having the formula ##STR2## or the 1,2-dehydro derivative thereof, with ozone and an alkanol having the formula R.sub.3 --OH and then treating the reaction mixture with a reducing agent; wherein R'.sub.1 is hydrogen, acyloxy or halogen; R.sub.3 is alkyl; R.sub.4 is carbonyl, .beta.-hydroxymethylene, .beta.-chloromethylene or .beta.-bromomethylene; R.sub.5 is hydrogen, fluorine, chlorine or bromine; R.sub.6 is hydrogen, fluorine or methyl; and R.sub.7 is hydrogen, chlorine or bromine.
