Three New Benzoic Acid Derivatives from the Glandular Excretion of Eriodictyon sessilifolium (Hydrophyllaceae)

Abstract

Eriodictyon sessilifolium, an endemic Hydrophyllaceae of Baja California (Mexico), has been studied for the natural products exuded by glandular trichomes covering its leaves and stems. Major components of this exudate were isolated and identified by spectroscopic methods to be 4-hydroxy-3-(2,3-dihydroxy-3-methylbutyl)-benzoic acid methyl ester (1), the natural methyl ester of anodendroic acid (2), and 2,2-dimethyl-3-hydroxychroman-6-carboxylic acid methyl ester (3). Possible biosynthetic relations between these new natural products are considered. In addition, 9 known flavonoid aglycones were identified as exudate constituents.

New Polyketides and New Benzoic Acid Derivatives from the Marine Sponge-Associated Fungus Neosartorya quadricincta KUFA 0081

“…Anodendroic acid was later synthesized by Yamaguchi et al [ 16 ]; however, its 1 H NMR data (DMSO- d 6 ) were slightly different from those reported by Shima et al [ 15 ]. Anodendroic acid was also obtained by basic hydrolysis of its methyl ester, a constituent of Eriodictyon sessilifolium [ 17 ], and also by biotransformation of 3-(γ,γ-dimethylallyl)- p -coumaric acid [ 18 ]. It is interesting to note that, in all of these reports, the identity of anodendroic acid was achieved by comparing its melting point, 1 H NMR and MS data with those reported by Shima et al [ 15 ], while no stereochemistry of C-2 was indicated.…”

Structure Revision of Four Classes of Prenylated Aromatic Natural Products Based on a Rule for Diagnostic 13C NMR Chemical Shifts

“…The combined organic phases were washed with brine (80 mL), dried over anhydrous Na 2 SO 4 , and filtered. After removal of the solvent under vacuum, the residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc = 40:1) to provide 4 (117 mg, 92% yield) as a white amorphous powder …”

“…The reaction mixture was stirred at r.t. for 20 min until completion (monitored by TLC analysis). The organic solvent was removed by rotary evaporation, and then, the residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc = 20:1) to provide 9 (121 mg, 96% yield) as a colorless oil Table .…”

“…The reaction mixture was stirred at 90 °C for 12 h. The reaction was quenched by saturated NH 4 Cl aqueous solution (20 mL), and the resulting aqueous layer was extracted with EtOAc (3 × 20 mL). After removal of the solvent under vacuum, the residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc = 20:1) to provide 10 (47 mg, 76% yield) as a colorless oil Table .…”

“…After removal of the solvent under vacuum, the residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc = 40:1) to provide 4 (117 mg, 92% yield) as a white amorphous powder. 28 1 H NMR (DMSO-d 6 , 400 MHz) δ H 10.17 (1H, br. s, OH-4), 7.79 (1H, d, J = 2.3 Hz, H-2), 7.65 (1H, dd, J = 8.4, 2.3 Hz, H-6), 6.84 (1H, d, J = 8.4 Hz, H-5), 4.60 (1H, s, OH-2′), 4.23 (1H, s, OH-3′), 3.77 (3H, s, H−COOCH 3 ), 3.40 (1H, dd, J = 10.3, 1.9 Hz, H-2′), 2.94 (1H, dd, J = 14.0, 1.9 Hz, H-1′a), 2.34 (1H, dd, J = 14.0, 10.3 Hz, H-1′b), 1.11 (3H, s, H-4′), 1.09 (3H, s, H-5′); 13 C{ 1 H} NMR data, see Table 1.…”