Abstract: The inner salt 2-acetamido-5-bromophenyl tellurium trichloride was synthesizedfrom p-bromoaniline by mercuration,acetylation and electrophilic substitution of tellurium tetrachloride successively.Reduction of the above salt with sodium borohydride followed by cyclization with concentrated hydrochloride and neutralization with sodium bicarbonate gave the key intermediate 2-methyl-6-bromobenzotellurazole. The latter was alkylated with methyl or ethyl iodide and then condensed with ethyl orthoformate to give two symmetric telluracarbocyanine dyes. The visible absorption of the dyes was also measured.

Key words: Benzotellurazole, Cyanine dye, Telluracarbocyanine dyes, Spectral sensitizer, Synthesis