The condensation of 4.02 g. (0.01 mole) of 2-(2-anilinovinyl)-1-ethylquinolinium iodide (prepared as described in British Pat. No. 344,409 m.p. 263°-5° C. (dec.)) with 2-cyano-4-nitrotoluene (1.67 g., 0.01 mole) was effected in 15 ml. of dimethylformamide containing 2 ml. of acetic anhydride by heating the reaction mixture to reflux, adding 1.01 g. (0.01 mole) of triethylamine, heating at reflux for 1 to 2 minutes and cooling rapidly. The precipitate was collected, washed successively with dimethylformamide, water and ether and then dried to yield 47% of theory of blue dye base m.p. 250°-252° C.
