Figure_2.tif (388.37 kB)
General scheme used for preparation of pyran naphthoquinones.
figure
posted on 2013-12-20, 03:35 authored by Emmerson C. B. da Costa, Raquel Amorim, Fernando C. da Silva, David R. Rocha, Michelle P. Papa, Luciana B. de Arruda, Ronaldo Mohana-Borges, Vitor F. Ferreira, Amilcar Tanuri, Luciana J. da Costa, Sabrina B. FerreiraThe o-QM intermediate is generated in situ by Knoevenagel condensation of 2-hydroxy-1,4-naphthoquinone (7) with formaldehyde and arylaldehydes. The subsequent hetero Diels-Alder reaction with substituted dienophiles in aqueous ethanol media yields high amounts of α- and β-lapachone derivatives.
