Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... An efficient, versatile, and scalable route for the synthesis of 7-aza-α-carboline compounds is described. The tricyclic system has been prepared from modified pyrazinones using a key intramolecular [4+2] Diels–Alder transformation. ... 7-Aza-α-carboline core. 7-Aza-α-carboline core.