Two isolated intermediates of the Tröger's base: synthesis and mechanism

Abstract By controlling the amount of catalyst 1-methyl-3-(2-(sulfooxy)ethyl)-1 H -imidazol-3-ium chloride, two new intermediates of Troger's bases ( 11 , 1,6-dimethyl-3-(4-methylphenyl)-1,4-dihydroquinazolin-3-ium tetrafluoroborate and 12 , 8-methyl-2,5-bis-(4-methylphenyl)-3,5,6,7-tetrahydropyrimido[5,6,1- ij ]quinazoline-2-ium tetrafluoroborate) were simply obtained from the one-pot reaction of aromatic amine and formaldehyde in ionic liquid at ambient temperature. These results support the mechanism for Troger's base formation supposed by Fernando Coelho and co-workers. However, the crystal structure of 12 and correlative quantum chemistry calculation results are not reconciled with their report.