PURPOSE: To readily obtain the titled compound useful as a phytohormone, by reacting a specific novel steroid with a peracid in an inert solvent.

CONSTITUTION: 1mol novel steroid expressed by formula I [R1 and R2 are H or OH-protecting group; R5 and R6 are H, lower alkyl, cycloalkyl or (substituted) phenyl; R5 and R6, together with the carbon atom to which they are linked, may form a cycloalkyl ring] is reacted with preferably 1W5mol peracid, preferably trifluoroperacetic acid in an inert solvent at -20W+50°C to afford the aimed compound expressed by formula II. The starting raw material novel steroid can be produced by reacting a steroid compound expressed by formula III (R7 and R8 are H or OH-protecting group; R3 and R4, together with the carbon atom of the ring to which they are linked, may form carbonyl or ketal) with a compound expressed by formula IV.