Two spirolactones and a naphthoquinone of Sinningia reitzii from Paraná state, Brazil

Two novel spirolactones, reitziiolide A (1) and reitziiolide B (2), and a new naphthoquinone, 6,7-dimethoxystreptocarpone (3), were isolated from the tubers of Sinningia reitzii (Hoehne) L. E. Skog (Gesneriaceae) from Paraná State, Brazil. In addition, six known compounds were also identified: 6-hydroxy-7-methoxy-α-dunnione (4), 2,4′-dihydroxy-4,6-dimethoxydihydrochalcone (5), loureirin B (6), 8-hydroxy-7-metoxy-2-O-methylstreptocarpone (7), 6,7-dimethoxydunnione (8), and 5-hydroxy-6,7-dimethoxydunnione (9). All compounds were analyzed by NMR 1D and 2D. Additionally, 1 and 2 were analyzed by X-ray diffraction. Compounds 4-5 are being reported for the first time in S. reitzii.