A single‐step synthesis of 5,6‐dihydropyrrolo[2,1‐a]isoquinolines and evaluation of their anti‐leukemic activity.

While a pharmaceutically intriguing scaffold, 5,6‐dihydropyrrolo[2,1‐a]isoquinoline (DHPIQ), has precedently been prepared from diverse tetrahydroisoquinolines (THIQs) using elaborate conditions, convenient metal‐free methods were discovered from condensation of cyanomethylene‐THIQ (1) and α‐halo‐ketones or aldehydes (1a) to afford 15 DHPIQs (2–16) in moderate yields by employing unique reactivities of the secondary amine and α‐carbon to the nitrile of 1. Preliminary biological studies with chronic myelogenous leukemia K562 and adriamycin‐resistant K562 (K562/ADM) cells exhibited some of the DHPIQs tested were active in the both cell lines. In particular, cyclohexyl‐fused DHPIQ (10) showed GI50 values of 9.79 and 13.60 μM in K562 and K562/ADM cells, respectively. Based on the flow cytometry analysis of 10, the anti‐cancer activity could be from apoptosis‐related mechanisms. Overall, this DHPIQ scaffold may be further optimized to discover clinically meaningful anti‐leukemic agents overcoming adriamycin resistance. [ABSTRACT FROM AUTHOR]