Abstract Reaction of 2, 4-di-tert-butylphenol with urotropin in conditions of Duff reaction takes an abnormal route and instead of the expected di-tert-butylsalicylaldehyde provides a mixture of N-substituted 3, 5-di-tert-butyl-2-hydroxybenzylamines and redox conjugate benzoxazines containing mostly 6, 8-di-tert-butyl-3-(3, 5-di-tert-butyl-2-hydroxybenzyl)-2 H- 3, 4-dihydrobenz [e][1, 3] oxazine. A solvolysis of an individual benzoxazine in the system ...