Synthesis of Various Substituted Benzo[c]-2,7-naphthyridines and an Approach towards the Skeleton of Meridine. Considerations about the Effect of Copper(II) Oxide

Abstract

Derivatives of benm[c]-2.7-naphthyridineshave been prepared in good yields and in one step through the use of the Pd(0)-catalyzed cross couplings of Cfonnyl-and bacetyl-3-pyridyluimethylstannanes with onho-bromoacetanilides.Perlolidine, an alkaloids present in perennial rye grass, was readily prepared in a few steps taking advantage of the cross coupling.An approach towards the pentacyclic ring skeleton of meridine has also been made, leading to several new derivatives of benza[c]-2.7-naphthyridine.All cross couplings are greatly promoted by the addition of staichiometric amounts of copper(I1) oxide and a comparison with the use of other catalytic systems in the Pd(0)-catalyzed cross couplings is made.