The synthesis of 4,7-dimethoxy 5- and 6-azaindoles, a structural unit that is present in recently developed anti-HIV-1 agents, was achieved in a regioselective manner. The developed strategy is based on the appropriate choice of a protecting group during a lithium-mediated formylation step, followed by thermal cyclization of azidoacrylates.
towards BBr3-mediated selective monodemethylation and oxidative demethylation reactions were also investigated. The regioselectivity of the deprotection was confirmed using a chemical approach. Oxidation reactions were then carried out on either dimethoxy- or hydroxymethoxyazaindoles, in different solvents, using [bis(trifluoroacetoxy)iodo]benzene. In acetonitrile-water, trioxopyrrolopyridines 12 were obtained