Stable azomethine imines having a 3,4-dihydroisoquinoline fragment and their cycloaddition to N-arylmaleimides

Article abstract of DOI:10.1134/S1070428011040129

Aroylation of 5,6,8,8a,13,14,16,16a-octahydro[1,2,4,5]tetrazino[6,1-a : 3,4-a']diisoquinoline or 1,3,4,8b-tetrahydro[1,2]diazireno[3,1-a]isoquinoline, as well as reactions of 2-(2-bromoethyl)benzaldehyde with aroylhydrazines followed by treatment with triethylamine, led to the formation of stable azomethine imines, aroyl(3,4-dihydroisoquinolinium-2-yl)azanides. 1,3-Dipolar cycloaddition of the latter to N-mesitylmaleimide was stereoselective: the ratio of the trans- and cis-adducts was (3-7) : 1, the former prevailing. The reactions with N-arylmaleimides having no ortho-substituents in the aryl group gave the corresponding cisadducts as the major products [trans/cis ratio 1 : (2.5-10)]. Pleiades Publishing, Ltd., 2011.