Reactions of biogenic amines with quinones

Abstract

Reactions of benzo-1,4-quinone with 2-phenylethylamine and p-tyramine produced the novel 2,5- diamino-derivatives (2b,c), analogous to 2,5-dianilinobenzo-1,4-quinone (2a). 2,5-Dihydroxybenzo- 1,4-quinone (3) reacts with aniline to form the tetrol (4a) and not 2,5-dianilinobenzo-1,4-quinone (2a) as previously reported. This tetrol (4a) may hydrolyse to form the monoimine (5a). Only in boiling aniline was the 2,5-dianilino derivative (2a) produced from the tetrol (4a). Novel tetrols were similarly isolated from 2-phenylethylamine, p-tyramine and histamine. Benzo-1,2-quinone reactions with aniline and the above amines were also studied. Implications of these reactions for the extraction of amines from foods are discussed.