Reactions of Anils with Active Methyl Group. (1)

Abstract

Anils obtained by the reaction of aromatic aldehydes and aniline or ammonia, e.g. Schiff's base, hydrobenzamide, etc., react with cyclic ammonium base possessing active methylene radical and form styryl dyes. This method has the advantage over the use of free aldehydes in that, formation of by-product isocyanines could be prevented by the elimination of condensation reagent, and that anils are more stable compared to free aldehydes. Trimethincyanine is formed by the reaction of cyclic ammonium salt possessing active methylene instead of formaldehyde on trimer-methylene-aniline and methylene-dianiline.