Synthesis of novel 1,2,3,4-tetrahydrobenzo[c]-1,5-naphthyridines from pyrrolo[1,2-b]isoquinolines

1,2,3,4-Tetrahydrobenzo[c]-1,5-naphthyridine ( 5a ) was prepared by a novel synthetic route involving the rearrangement of (±)-(Z)-1,10a-dihydropyrrolo[1,2-b]isoquinoline-3,10(2H,5H)-dione oxime to afford 1,4-dihydrobenzo[c]-1,5-naphthyridin-2(3H)-one, which was reduced to 5a. The cholinomimetic activity observed with 5a prompted the synthesis and biological evaluation of additional analogues.