Gypmacrophin A, a Rare Pentacyclic Sesterterpenoid, Together with Three Depsides, Functioned as New Chemical Evidence for Gypsoplaca macrophylla (Zahlbr.) Timdal Identification

Abstract

The phytochemical investigation on 1 g of materials from Gypsoplaca macrophylla (Zahlbr.) Timdal resulted in the discovery of gypmacrophin A, a rare pentacyclic sesterterpenoid; brialmontin III, a new polysubstituted depside and two known ones, brialmontins I and II. The structure and absolute configurations of gypmacrophin A were elucidated by spectroscopic analyses and computational methods. Gypmacrophin A showed weak inhibition of AchE with an IC50 value of 32.03 μM. The four compounds provided new chemical evidence for G. macrophylla identification.

3-Hydroxy-4-methyldecanoic Acid-Containing Cyclotetradepsipeptides from an Endolichenic Beauveria sp.

“…was isolated from Gypsoplaca macrophylla (Zahlbr.) Timdal, a lichen reported as the source of a rare pentacyclic sesterterpenoid, gypmacrophin A . An investigation on the cultures of this fungus led to the discovery of seven new cyclotetradepsipeptides, beauveamides A–G ( 2 – 8 ), along with the known beauverolide Ka ( 1 ), all containing an HMDA moiety.…”

Asymmetric Total Synthesis of Bufospirostenin A

“…Notably, the synthetically challenging [5–7–6–5] tetracyclic ring system, such as in 1 , is also found in other natural products (such as compounds 2 – 5 ; the ring system is highlighted in red in Figure ). Therefore, the development of a general strategy for efficiently synthesizing these fascinating targets to explore their medicinal potential is highly desirable. However, to the best of our knowledge, there are few approaches reported regarding the synthesis of such a [5–7–6–5] tetracyclic ring system .…”