Addition von Maleinimiden an Azine

Abstract

Aromatic aldazines add 2 moles of N-Alkylated maleinimides in the same manner as they add maleic anhydride in 1,3-2,4-position (criss-cross addition). The configuration of the 3 stereo-isomeres is discussed which are formed by addition of N-n-butylmaleinimide to benzaldazine with a yield of at least 65%. Only 3% of an 1:1-addition product could be isolated.
The addition of N-alkylated maleinimides to cycloaliphatic aldazines occurs, at least in certain instances, with deplacement of hydrogen as a Michael-addition. With cycloaliphatic ketazines this type of addition prevails or happens exclusively.
A third type, described only recently, is the addition of one mol of a β-lactone to one mol of a benzaldazine in 1,3-position, with loss of CO₂, forming 1-benzyl-3-phenyl-2-pyrazolines.