Process for the preparation of triarylmethane compounds

Process for the preparation of a triarylmethane compound of the formula (I):

• ##STR41## wherein A is a benzene compound as defined by formula (II) below or a naphthalene compound as defined by formula (III) below and Q--R is a benzene compound as defined by formula (IV) below or a naphthalene compound as defined by formula (V) below, which comprises:
• reacting a benzene compound of formula (II):
• ##STR42## or a naphthalene compound of formula (III):
• ##STR43## wherein X is a lower alkoxy group, an --NR.sub.1 R.sub.2 group, in which R.sub.1 and R.sub.2 are each a lower alkyl group, phenyl group or benzyl group, a morpholino group or a pyrrolidinyl group, R is a hydrogen atom, a halogen atom or a cyclohexyl group, and n is an integer of 1 to 3, with a formamide or formanilide compound in the presence of an acid catalyst selected from the group consisting of phosphorus oxychloride, phosphorus oxybromide, phosgene and thionyl chloride, to form an aromatic aldehyde;
• adding water to the reaction mixture containing the aromatic aldehyde and thereby hydrolyzing the acid catalyst;
• and uninterruptedly reacting, in the resultant mixture, the aromatic aldehyde with a benzene compound of formula (IV):
• ##STR44## or a naphthalene compound of the general formula:
• ##STR45## wherein X is an --NR.sub.1 R.sub.2 group, in which R.sub.1 and R.sub.2 are each a lower alkyl group, phenyl group or benzyl group, a morpholino group or a pyrrolidinyl group, R is a hydrogen atom, a halogen atom, a lower alkyl group or a cyclohexyl group, and n is an integer of 1 to 3, thereby forming the triarylmethane compound at a high yield and in a high purity.