| abstract |
PURPOSE:The reaction of 3,4-dichloro-3-cyclobutene-1,2-dione with an aniline derivative is followed by hydrolysis of the product to give, in high selectivity, the titled compound of high purity which is an intermediate of squarylium compound used as a photoconductive material. CONSTITUTION:The reaction between a compound of formula I and another compound of formula II [X is H, alkyl which may be substituted, halogen, hydroxyl, phenyl which may be substituted, alkyl-bounded carbonamide or sulfonamide; R1, R2 are alkyl, phenyl or benzyl, respectively, which may be substituted] is carried out at 0-80 deg.C, preferably 0-40 deg.C to form chlorocyclobutenedione derivative of formula III. Then, the product is hydrolyzed to give the objective compound of formula I. The reaction proceeds satisfactorily without a catalyst to give the objective compound of higher purity than the product obtained in the presence of a Lewis acid catalyst of 0.1-1 equiv. |