Studies on the Ultraviolet Absorption Spectra of Coumarins and Chromones. II. Hydroxy Derivatives¹

Altechromones A and B, New Plant Growth Regulators Produced by the Fungus,Alternariasp.

“…(No.1) and succeeded in isolating two new metabolites designated a1techromones A (1) and B (2). This paper deals with the isolation, structural elucidation and biological activity of these two compounds.…”

Secondary Metabolites From Peperomia Sui

“…1) , m/z 426) and HREIMS. The IR spectrum displayed strong absorptions at 3400 cm -1 (hydroxyl group) and 1652 cm -1 (carbonyl group), which were characteristic of 5-hydroxy-2-alkylchromone moiety 10,11 and supported by the UV spectrum (λ max at 231 and 327 nm). The structure of 5-hydroxy-2-alkyl-chromone moiety was confirmed by the 1 H NMR spectrum of 2, which contained three mutually coupling protons belong an ABC-type system at δ 6.77 (1H, d, J = 8.2 Hz), 6.86 (1H, dd, J = 8.2, 0.4 Hz) and 7.50 (1H, t, J = 8.2 Hz) corresponding to H-8, 6 and 7, one deshielding olefinic proton at δ 6.11 (1H, s) and a singlet at δ 12.59 (1H, s) ascribable to a chelated hydroxyl group at C-5.…”

Structure and Biological Activity of Plant Growth Regulators Produced byPenicilliumsp. No. 31f

“…the UV spectrum of 1 was very similar to that of 7-hydroxy-2-methylchromone 4 ) [UV A max EtOH nm (log e): 215 (4.33), 244 (4.24), 249 (4.32), 290 (4.04)]. The NMR data of 1 are shown in Table I.…”