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Abstract: Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3), were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473), one of important cancer drugs target. [ABSTRACT FROM AUTHOR]

S-Glycosides are considerably more stable toward chemical degradation and enzymatic hydrolysis than O-glycosides, and thioglyco-peptides/proteins also demonstrate critical bioactivities in the living system. However, the general and stereoselective synthetic strategies are still challenging. Herein, a versatile S-glycosylation approach was developed by palladium-catalyzed allylic substitution to form a- and ß-thioglycosides respectively under mild conditions. A wide range of substrates were tolerated to afford thioglycosides in a stereospecific manner with 70%-86% yields. This protocol also created the quick access to various S-linked disaccharides and glycopeptides. [ABSTRACT FROM AUTHOR]

The special electronic configuration of phosphorus atoms endows organophosphorus reagents with unique chemical properties, which enable them to be used to catalyze various organic reactions, such as the Wittig reaction, Staudinger reaction, Appel reaction and Mitsunobu reaction. However, the catalytic process will be accompanied by the generation of large amounts of phosphine oxide waste, resulting in the reduction of atom utilization of the reaction, and it is difficult to separate the product. Therefore, it is essential to explore a greener and more sustainable organic synthesis route based on the catalytic cycle of phosphine oxide as a model. This paper summarizes the catalytic cycle and recycling of phosphorus with or without reducing agents and reviews the related developments in recent decades: from the addition of stoichiometric strong reducing agents, to the design of ring phosphines with specific structures, to the development of new energy inputs (electrochemistry), to the addition of a series of compounds to activate the P(V)- - O double bond, driving the catalytic cycle of phosphine oxide through chemical transformation. This review also points out the development potential of this field in the future, which will promote its development and progress in a greener direction. [ABSTRACT FROM AUTHOR]

Seeking a strategy for triggering the cryptic natural product biosynthesis to yield novel compounds in the plant-associated fungus Xylaria sp., the effect of culture conditions on metabolite production was investigated. A shift in the production of five known cytochalasin-type analogues 1-5 to six new α-pyrone derivatives, xylapyrones A-F (compounds 6-11), from a solid to a liquid medium was observed. These compounds were identified by analysis of 1D and 2D NMR and HRMS data. Compounds 1-3 showed moderate cytotoxicity against HepG2 and Caski cancer cell lines with IC50 values ranging from 25 to 63 μM and compounds 4-11 were found to be inactive, with ICY50 values >100 μM. [ABSTRACT FROM AUTHOR]