A Novel Two-Step Synthesis of Hexahydropyrazino[1,2-α]-quinolines

All articles of this category The hexahydropyrazino[1,2- a ]quinolines 2 were prepared in good yields by reaction of 2-(4-substituted 1-piperazinyl)benzaldehydes 5 with malononitrile and subsequent thermal cyclization of the condensation products 6 ; the latter reaction takes place via a concerted [1,5] hydrogen transfer and subsequent ring closure by addition of a carbanion to the iminium double bond.