To obtain a new derivative having an oxetane ring on a side chain, and having excellent pharmacological activity as an osteogenesis stimulating agent, a bone resorption suppressing agent or the like.
A derivative of formula I [R1 and R2 are each H or a protective group for OH; R3 is H, F, Cl or a (substituted) 1-2C alkyl; R4 is H, F, Cl or a (substituted)methyl; X1 is F or Cl; X2 is H, F or Cl; and n=1-3] or its prodrug, for example, (5Z,5E)-23S,25-epoxy-26,26,26,27,27,27-hexafluoro-9,10- secocholesta-5,7,10(19)-triene-1α,3β-diol. Further, the compound is obtained by reacting a compound of formula II with a halide of a corresponding sulfonyl compound in an aprotic solvent such as dichloromethane at a temperature from 0°C to the boiling point of the solvent in the presence of a base such as pyridine, and treating the obtained compound with an alkali.
TANAKA TOMOYUKI
NOGUCHI TOSHIHIRO
MATSUMURA HARUKI
