Norprzewalsone A, a Rearranged Polycyclic Polyprenylated Acylphloroglucinol with a Spiro[cyclopentane-1,3′-tricyclo[7.4.0.0^1,6]tridecane] Core from Hypericum przewalskii

Abstract

Norprzewalsone A (1), a rearranged polyprenylated polycyclic acylphloroglucinol (PPAP) with a new carbon skeleton, along with a new congener, norprzewalsone B (2), were isolated from Hypericum przewalskii. Compound 1 possessed a new 5/6/5/6/6 pentacyclic ring system based on a spiro­[cyclopentane-1,3′-tricyclo­[7.4.0.01,6]­tridecane] core, which might be derived from the common [3.3.1]-type bicyclic polyprenylated acylphloroglucinol (BPAP) via the key retro-Claisen, intramolecular cyclization, and Diels–Alder cyclization reactions. Their structures and absolute configurations were confirmed by spectroscopic data, calculated 1D NMR data with DP4+ probability analyses, and electronic circular dichroism calculations and comparison. More significantly, compound 1 exhibited a moderate inhibitory effect on NO production in lipopolysaccharide-stimulated RAW264.7 cells.

Hyperpatone A, a polycyclic polyprenylated acylphloroglucinol with a rare 8/6/5/6/5 pentacyclic skeleton from Hypericum patulum

“…30 As shown in Fig. 6, at a lower concentration of 5 or 1 μM, 33 compound 1 showed inhibitory potency with inhibition rates of 26.5 and 21.8%, respectively.…”

Spirohypertones A and B as potent antipsoriatics: Tumor necrosis factor-α inhibitors with unprecedented chemical architectures

“…S1 ). Considering the chemical shift of C-21 located at a field region at δ C 84.7 ( Supporting Information Table S1 ), and the characteristic absorption band at 1775 cm −1 in IR spectrum, resembling the known compounds possessing the similar five-membered lactone ring, we speculated that 1a should be more reasonable 18 , 20 , 21 , 22 . Therefore, the planar construction of 1 , possessing a highly rearranged carbon architecture, was finally defined.…”

“…Spirohypertones A ( 1 ) and B ( 2 ) were highly functionalized and rearranged PPAPs with unparalleled carbon skeletons, diverging from the known PPAPs 11 , 18 , 22 , 23 , 24 , 25 , 26 , 27 . Thus, a plausible biogenetic pathway was proposed.…”

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“…9) from Hypericum beanii and norprzewalsone A 12 from Hypericum przewalskii . 10 Biosynthetic pathways have been proposed for all three acylphloroglucinols. The structure of valeriaquinone A 13 , isolated from the roots of Knoxia valerianoides , was established by X-ray analysis.…”