Tricrilactones A–H, Potent Antiosteoporosis Macrolides with Distinctive Ring Skeletons fromTrichocladium crispatum, an Alpine Moss‐Associated Fungus

Abstract

Tricrilactones A–H (1–8), a new family of oligomeric 10‐membered macrolides featuring collectively five unique ring skeletons, were isolated from a hitherto unexplored fungus, Trichocladium crispatum. Compounds 1 and 7 contain two unconventional bridged (aza)tricyclic core skeletons, 2, 3, 5, and 6 share an undescribed tetracyclic 9/5/6/6 ring system, 4 bears an uncommon 9/5/6/10/3‐fused pentacyclic architecture, and 8 is a dimer bridged by an unexpected C−C linkage. Their structures, including absolute configurations, were elucidated by spectroscopic analysis, quantum chemical calculations, and X‐ray diffraction analysis. Importantly, the absolute configuration of the highly flexible side chain of 1 was resolved by the asymmetric synthesis of its four stereoisomers. The intermediate‐trapping and isotope labeling experiments facilitated the proposal of the biosynthetic pathway for these macrolides. In addition, their antiosteoporosis effects were evaluated in vivo (zebrafish).

Bufadienolide-Fatty Acid Conjugates from the Fertilized Eggs of Toad Bufo gargarizans: Isolation, Characterization, Toxicity, and Antiproliferative Evaluation

“…Parameters for molecular network generation were set as follows: precursor ion mass tolerance m / z 0.02 Da, MS 2 fragment ion tolerance m / z 0.2 Da, minimum cosine scores 0.65, and minimum matched fragment ions 6. The result of the molecular network was visualized using Cytoscape 3.9.1. , The specific molecular networking information can be accessed as followed:…”

“…The result of the molecular network was visualized using Cytoscape 3.9.1. 20,21 The specific molecular networking information can be accessed as followed: h t t p s : / / g n p s . u c s d .…”

Polyketides with α-glucosidase inhibitory and neuroprotective activities from Aspergillus versicolor associated with Pedicularis sylvatica

“…19 However, endophytic fungi associated with Pedicularis sylvatica L. have rarely been investigated. In continuing research into endophytic fungi, [20][21][22] a fungus associated with Pedicularis sylvatica produced four undescribed metabolites, aspeversins A-D (1, 2, 5 and 6), and four known compounds (3, 4, 7 and 8) (Fig. 1), which showed α-glucosidase inhibitory and neuroprotective activities.…”

Polyarylisocyanides Derived from an Alkyne-Pd(II) Catalyst as Robust Alignment Media with Excellent Enantiodiscimination

“…Over the past two decades, anisotropic NMR spectroscopy, including residual dipolar coupling (RDC), residual chemical shift anisotropy (RCSA), and residual quadrupolar coupling (RQC), has made significant advancements in the structural determination of organic molecules. − These anisotropic parameters provide precise spatial information at the atomic level, enabling the determination of the constitution, relative configuration, and three-dimensional conformation of novel and complex natural products and other chemical systems with increasing accuracy. − Recent approaches, such as Bayesian inference-based floating chirality distance geometry or model-free analysis, have further enhanced the accuracy of interpreting RDC data for flexible molecules. , However, despite its immense potential, the determination of absolute configuration using anisotropic NMR has not yet experienced a major breakthrough …”