PURPOSE: To readily obtain a compound useful as a synthetic intermediate for coloring matter in pressure-sensitive recording paper or heat-sensitive recording paper under mild condition without requiring a special device, by oxidizing a diphenylalkanoic acid derivative.
CONSTITUTION: A compound expressed by formula I (R1 and R2 are H, alkyl, cycloalkyl, aralkyl or aryl or together may link or with the adjacent benzene ring form a heterocyclic ring; R3WR11 are H, halogen, alkyl, hydroxyl or amino; R12 and R13 are H or alkyl; X is carboxyl or amide thereof, ester or halide) is oxidized to afford a compound expressed by formula II. The reaction is carried out by using an oxidizing agent, e.g. lead dioxide, etc., free of or in an organic solvent, e.g. acetone, at -5W+150°C.
OMURA HARUO
ABE YUKIHIRO
KONDO MITSURU
Next Patent: 4,4'-BIS(3-(4-AMINOPHENOXY)BENZOYL)DIPHENYL ETHER AND PRODUCTION THEREOF