摘要 |
<p>A process for the preparation of a compound of Formula (1): <CHEM> wherein: W<1> is aryl; X<1> and X<2> are each independently selected from -H, -CN, halogen, alkyl, aryl and -COOH; Y is -H; Z is -OH; or Y and Z together form a group of Formula (2): <CHEM> wherein: W<2> is aryl; which comprises reacting a compound of Formula (3): <CHEM> wherein: X<1>, X<2>, Y and Z are as hereinbefore defined with a compound of Formula (4): <CHEM> wherein: R is -H or -alkyl; A is selected from -H, -COOR, -OR and aryl in which R is as hereinbefore defined; and W<1> and W<2> are as hereinbefore defined, in the presence of an acid catalyst characterised in that the catalyst is a long chain alkyl- or long chain alkylaryl-sulphonic, disulphonic or phosphonic acid. The compounds of Formula (1) are polycyclic dyes or are intermediates used in the preparation of such dyes. The use of long-chain alkyl- or long-chain alkylaryl-sulphonic, disulphonic or phosphonic acids offers a number of advantages such as higher product yield, better physical form and hence better recovery by filtration and improved recovery of reaction solvents.</p> |