Process for preparing 1,2-dehydro steroids

A process for preparing a 1,2-dehydro-.DELTA..sup.4 -3-keto steroid selected from the group consisting of ##STR5## R.sub.6 is a hydrogen or fluorine atom or methyl group. R.sub.6 ' is a hydrogen atom or methyl group.

• R.sub.9 is nothing, a hydrogen, fluorine or oxygen atom which makes the C ring
• (a) .DELTA..sup.9(11) when R.sub.9 is nothing and
• (b) 9.beta.,11.beta.-epoxide when R.sub.9 is an oxygen atom;
• R.sub.11 is a hydrogen or oxygen atom, two hydrogen atoms, or .alpha.- or .beta.-hydroxyl group which makes the C-ring
• (a) .DELTA..sup.9(11) when R.sub.11 is a hydrogen atom,
• (b) 9.beta.,11.beta.-epoxide when R.sub.11 is an oxygen atom and between C.sub.11 and R.sub.11 is a single bond, and
• (c) a ketone when R.sub.11 is an oxygen atom and between C.sub.11 and R.sub.11 is a double bond;
• indicates that the attached group can be in either the .alpha. or 62 configuration;
• is a single or double bond;
• R.sub.1l 40 is a .beta.-hydroxyl group, an oxygen atom (11-ketone), or hydrogen atom (.DELTA..sup.9(11));
• R.sub.16 is a hydrogen atom or methyl group;
• R.sub.16 ' is a hydrogen atom, methyl or hydroxyl group, when R.sub.16 ' is an .alpha.-hydroxyl group the 16.alpha. and 17.alpha.-hydroxyl groups can be in the form of an acetonide;
• R.sub.21 is a hydrogen atom or --OC--OR.sub.21 40;
• R.sub.21 ' is methyl, ethyl, or phenyl which comprises exposing the corresponding 1,2-saturated-.DELTA..sup.4 -3 keto steroid to air-dried or heat-dried cells of Arthrobacter simplex having a moisture content of about 1 to about 10% where the cells are dried in the absence of an organic solvent.