Collect. Czech. Chem. Commun. 1990, 55, 2502-2509

An unusual tert-butylamine mediated conversion of 6-aryl-7-formyl-2,4,5,8-tetrahydro-1,3-dioxa-5-azocines to 1,2,3,6-tetrahydropyrimidine derivatives

Ladislav Štibrányi, Lubor Fišera, Rastislav Káčer, Vladimír Oremus and Martina Mihulová

Department of Organic Chemistry, Slovak Institute of Technology, 812 37 Bratislava


An unexpected contraction of the 8-membered ring to a 6-membered one occurring when 6-aryl-7-formyl-2,4,5,8-tetrahydro-1,3-dioxa-5-azocines II were treated with tert-butylamine afforded 4-aryl-5-formyl-1-(1,1-dimethylethyl)-1,2,3,6-tetrahydropyrimidines III. Reaction conditions for the photorearrangement of chlorophenyl-substituted condensed isoxazolines I to II were worked out. The reaction sequence: 1,3-dipolar cycloaddition, photochemical rearrangement, treatment with tert-butylamine constitutes a new route to pyrimidine derivatives from 2H,4H,7H-1,3-dioxepine.