A Simple Synthesis of the Debrominated Analogue of Veranamine

A facile synthesis of 4,5,5-trimethyl-5,6-dihydrobenzo[c][2,7]naphthyridine, the debrominated analogue of the marine alkaloid veranamine, has been achieved in three steps with a 38% overall yield. from the commercially available 2-bromoaniline. The key benzo[c][2,7]naphthyridine moiety was constructed using a Sonogashira coupling, a tandem Rupe rearrangement–Donnelly–Farrell cyclisation and a Diels–Alder reaction as the key steps. The synthetic strategy allows rapid access to various analogues of veranamine.