A convenient and economical method for preparing infrared absorbing cyanine dyes useful in lithographic printing plate precursors is disclosed. The reaction is generally carried out by condensation of a heterocyclic base containing an activated methylene group and an unsaturated bisaldehyde or its equivalent in a solvent or solvent mixture at about 20-150° C. All the reactions necessary for production of the infrared absorbing cyanine dye may be carried out in one reaction vessel without isolating any intermediate products.
本发明公开了一种制备适用于制作印刷版前体的红外吸收青光菁
染料的方便经济方法。通常通过在溶剂或溶剂混合物中,在大约20-150℃的条件下,将含有活性亚甲基基团和不饱和双醛或其等效物的杂环碱缩合反应来完成。制备红外吸收青光菁
染料所需的所有反应都可以在一个反应容器中完成,而无需分离任何中间产物。