The title compound, C(15)H(20)O(4), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The seven-membered ring has a chair conformation, while the five-membered rings display twisted conformations. The dihedral angle between the seven-membered ring and the lactone ring is 21.69 (10)°. In the crystal, mol-ecules are linked into chains propagating along the c axis by inter-molecular O-H⋯O hydrogen bonds; an intra-molecular O-H⋯O link also occurs.
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http://dx.doi.org/10.1107/S160053681102352X | DOI Listing |
J Exp Pharmacol
January 2025
University Center of Excellence for Nutraceuticals, Bioscience and Biotechnology Research Center, Bandung Institute of Technology, Bandung, West Java, Indonesia.
Purpose: A promising feature of marine sponges is the potential anticancer efficacy of their secondary metabolites. The objective of this study was to explore the anticancer activities of compounds from the fungal symbiont of on breast cancer cells.
Methods: In the present research, , an endophytic fungal strain derived from the marine sponge was successfully isolated and characterized.
Org Lett
January 2025
Key Laboratory of Chemical Biology and Traditional Chinese Medicine (Ministry of Educational of China), Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, China.
We disclose herein a chiral phosphoric-acid-catalyzed enantioselective addition reaction of alcohols to fluoroalkylated biaryl 1,3-oxoazepines, which furnished a wide range of bridged biaryls bearing a fluoroalkylated quaternary carbon stereocenter on the seven-membered ring in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). Our method can be used for the modification of several natural products and bioactive molecules. Preliminary studies revealed that the products obtained in this reaction exhibit good in vitro bioactivities against two plant pathogens.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Chiral medium-sized rings, albeit displaying attractive properties for drug development, suffer from numerous synthetic challenges due to difficult cyclization steps that must take place to form these unusually strained, atropisomeric rings from sterically crowded precursors. In fact, catalytic enantioselective cyclization methods for the formation of chiral seven-membered rings are unknown, and the corresponding eight-membered variants are also sparse. In this work, we present a substrate preorganization-based, enantioselective, organocatalytic strategy to construct seven- and eight-membered rings featuring chirality that is intrinsic to the ring in the absence of singular stereogenic atoms or single bond axes of chirality.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Hydrazides are known to catalyze reactions of α,β-unsaturated aldehydes via transient iminium formation. The iminium intermediate displays enhanced electrophilicity, which facilitates conjugate additions and cycloadditions. We observed that a hydrazide embedded in a seven-membered ring catalyzes homoaldol condensation of a simple aldehyde in a process that displays an approximate second-order dependence on the hydrazide.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Rice University, Houston, Texas 77005, United States.
Concise total syntheses of several 5/7/6 norcembranoids, including ineleganolide, scabrolide B, sinuscalide C, and fragilolide A have been achieved through a fragment coupling/ring closure approach. The central seven-membered ring was forged through sequential Mukaiyama-Michael/aldol reactions using norcarvone and a decorated bicyclic lactone incorporating a latent electrophile. Subsequent manipulations installed the reactive enedione motif and delivered scabrolide B in 11 steps from a chiral pool-derived enone.
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