Reaction ofN‐benzyl‐1,1′‐iminobis‐2‐butanols with 70% w/w sulfuric acid

Abstract

Treatment of (S:R)‐N‐benzyl‐1,1′‐iminobis‐2‐butanol with 70% w/w sulfuric acid gives cis‐ and trans‐N‐benzyl‐2,6‐diethylmorpholines (15 and 74%, respectively) and N‐alkenyl‐4‐ethyl‐1,2,3,4‐tetrahydroisoquinolines (5%). Hydrogenation of the reaction mixture gives cis‐ and trans‐2,6‐diethylmorpholines and N‐butyl‐4‐ethyl‐1,2,3,4‐tetrahydroisoquinoline. Neither N‐benzyl‐N‐crotyl‐(2‐hydroxy‐1‐butyl)amine (4) nor N‐benzyldicrotylamine (5) are intermediates in the reaction. (S:S)‐N‐Benzyl‐1,1′‐iminobis‐2‐butanol gives 95% of cis‐N‐benzyl‐2,6‐diethylmorpholine and 1% of the trans isomer.