A New Pyranocoumarin Diester from Polygala paniculata L

Abstract

A new coumarin diester has been isolated from Polygala paniculata L. (Polygalaceae) by a combination of flash chromatography on silica gel and preparative reversed‐phase chromatography. Its structure has been determined as 3′‐O‐acetyl‐4′‐O‐benzoylkhellactone (= 9‐acetoxy‐9,10‐dihydro‐8,8‐dimethyl‐2‐oxo‐2 H,8H‐benzo[1,2‐b:3,4‐b′]dipyranh‐10‐yl benzoate) by spectroscopic methods (UV, IR, 1H‐NMR, EI‐and CI‐MS) and by X‐ray analysis.

Coumarins

“…The first khellactone diester (1 58) with an aromatic acid moiety has been isolated from Polygala paniculata. 159 Two further khellactone derivatives have been found in Peucedanum praeruptorum roots, the diester Pd-I11 (159) and the keto ester Pd-Ib (163). 160 The first synthesis of (+)-praeruptorin A, also known as Pd-Ia (160), has been described.161 cis-Hydroxylation of seselin (168) was achieved by the catalytic osmium tetroxide hydroxylation procedure using a stoicheiometric amount of Nmethylmorpholine N-oxide.…”

Coumarins fromPolygala paniculata

“…Its IR spectrum showed absorptions at 3400, 1600, 1512, 1500 cm' (5), while its UV spectrum possessed maxima at 205, 232, 276 nm (6), suggesting the presence of a 4-aryltetralin skeleton. This was supported by an intense peak m/z 300 (M -56), due to RDA cleavage in the mass spectrum of 4-aryltetralin lignans (7). The 1H-NMR (Table I) The position of the hydroxyl group was determined by measurements of nuclear Overhauser effect (NOE as shown in Fig.…”

“…Recrystallization from n-heptane-AcOEt yielded compound 1 (10 mg). Fraction 5 contained a new pyranocoumarin diester, identified as 3 '-O-acetyl-4'-O-benzoylkhellactone by X-ray analysis (7). From fraction 7 (152 mg), after separation by centrifugal thin-layer chromatography with CHCI3-MeOH (99: 1) and recrystallization from n-heptane-AcOEt, 12 mg of compound 2 were obtained as colourless needles.…”

Molluscicidal Constituents ofCalophyllumfrom Madagascar: Activity of Some Natural and Synthetic Neoflavonoids and Khellactones

“…We prepared a series of analogs of khellactones in the hope of finding evidence for molluscicidal activity related to this chemical class. Khellactones have been isolated recently by Hostettmann et al (22,30) from Polygala paniculata L., which presented a molluscicidal activity on preliminary screening.…”