TETRAPHENYLBENZIDINE COMPOUND

PURPOSE:To provide the thermally and chemically stable new compound functioning effectively as a charge transport material, easily presenting vitreous state and maintaining the state stably, thus useful as a charge transport material in organic electroluminescent devices. CONSTITUTION:The compound of formula I(R1 and R2 are each H, lower alkyl or lower alkoxyl, and at least one of them is n-butyl, isobutyl, sec-butyl or t-butyl; R3 is H, lower alkyl, lower alkoxyl or Cl), e.g. N,N'-bis(p-n-butylphenyl)- N,N'diphenylbenzil can be obtained by the following processes: an aniline compound of formula II is N-acetylated into the corresponding anilide compound, which is, in turn, subjected to a haloaryl compound of formula III (X is Cl, Br or I) to conduct a condensation reaction, and the product is hydrolyzed to obtain a diphenylamine compound of formula IV, which is then condensed with a 4,4'-dihalobiphenyl of formula V.