Rivularin 2′-O-glucuronide (5-Hydroxy-7,8,6′-trimethoxyflavone-2′-O-β-D-glucuronapyranoside)

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Taxonomy: Physicochemical and Pharmacological Properties of Flavonoids – Flavons and Flavon-3-ols

Biological sources: Scutellaria rivularis [1]

C₂₄H₂₄O₁₃: 520.4482

Mp: 186–188°C (dec.) (MeOH)

[α]_D³⁰ + 32.7° (c 0.2, pyridine)

UV: 266 (4.28), 310 sh (3.69), 340 (3.61); +CH₃ONa: 270 (4.25), 376 (3.79); +AlCl₃: 277 (4.39), 320 sh (3.84), 400 (3.67); +AlCl₃/HCl, 270 (4.38), 320 sh (3.83), 400 (3.68); +CH₃COONa: 265 (4.39), 310 sh (3.83), 340 (3.71); +H₃BO₃/CH₃COONa: 265 (4.38), 310 sh (3.81), 340 (3.71) [1]

IR: 3456 (OH), 1735 (COOH), 1660 (C = O γ-pyrone), 1618, 1588 (C = C aromatic)[1]

FAB-MS: 521 [M + 1]⁺ (22) [1]

EI-MS: 344 [C₁₈H₁₆O₇ (aglycone)] (54), 329 [aglycone-CH₃] (100), 181 [C₉H₈O₅-CH₃] (26), 153 [C₉H₈O₅-CH₃-CO] (31) [1]

¹H NMR (DMSO-d₆): 3.70, 3.78, 3.91 (each 3H, s, OCH₃), 6.32 (1H, s, H-6), 6.61 (1H, s, H-3), 6.88 (1H, d, J = 8.4, H-3′ or H-5′), 6.92 (1H, d, J = 8.4, H-3′ or H-5′), 7.50 (1H, d, J = 8.4, H-4′), 3.06–3.86 (3H, m, H-2″,3″,4″), 3.84 (1H,...