Synthesis of 2[(4,6-diphenyl-2H-pyran-2-ylidene)methyl]-4,6-diphenylpyrylium perchlorate

The title compound was prepared by the condensation of 4,6-diphenyl-2H-pyran-2-one and acetophenone in phosphorus oxychloride. The absorption spectrum of this 2,2-methine dye is compared with those of the corresponding 2,4- and 4,4-methine dyes.