PURPOSE: To obtain the titled compound useful as a synthetic intermediate for reducing agents or antioxidants, etc. in high yield at a low cost, by subjecting the 5-position of a benzoxazole derivative to uncleophilic substitution reaction, and opening the oxazole ring.
CONSTITUTION: A benzoxazole derivative expressed by formula I [R1 is a group bonded through (substituted) carbon atom or a group bonded through N atom having no H; R2 and R3 are H or groups substitutive at the aromatic ring; X1 is Cl or Br] is subjected to the nucleophilic substitution reaction at the 5-position thereof, preferably reacted with X2- or X2H in a solvent, e.g. xylene, at 20W 120°C to give a compound expressed by formula II. The oxazole ring thereof is then opened by hydrolysis preferably under acidic conditions to afford the aimed compound expressed by formula III (R4 is H or -COR1; X2 is nucleophilic group).
ONO MITSUNORI
KOBAYASHI HIDETOSHI
YAMAKAWA KAZUYOSHI
