PURPOSE: To obtain the titled compound useful as a plant growth promoting substance, by reacting specific steroids with a peracid in an inert solvent containing an acid.

CONSTITUTION: Steroids [e.g. (22R,23R,24R)-22,23-dihydroxy-2α,3α-isopropylide dioxy-5α-ergostan-6-one] expressed by formula I {R1 and R2 are lower alkyl, aryl or together (CH2)n (n is 4 or 5); X is carbonyl (CO) or protected carbonyl [C(OCH2)2-]; R3 is H, methyl or ethyl} are reacted with a peracid (e.g. peracetic acid) in an inert solvent (e.g. dichloromethane) containing an acid, preferably at -20W+50°C to provide the aimed compound expressed by formula II.