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A novel oxadiazolone-based method for the synthesis of 3-aminobenzisoxazoles by N-O bond formation and of 2-aminobenzoxazoles through a Tiemann-type rearrangement has been developed. The synthesis of these two pharmaceutically relevant heterocycles was realized by an unexplored retrosynthetic disconnection using a cyclic nitrenoid precursor-based strategy. The selective formation of the two isomers was significantly influenced by steric and electronic effects of substituents. However, tetrabutylammonium chloride (TBACl) efficiently promoted the Tiemann-type rearrangement over N-O bond formation. Control experiments indicate that deprotonation of the phenol induces both rearrangements., (© 2022 The Authors. Published by Wiley-VCH GmbH.)

The biosynthesis gene cluster for the production of xenocyloins was identified in the entomopathogenic bacterium Xenorhabdus bovienii SS-2004, and their biosynthesis was elucidated by heterologous expression and in vitro characterization of the enzymes. XclA is an S-selective ThDP-dependent acyloin-like condensation enzyme, and XclB and XclC are examples of the still-rare acylating ketosynthases that catalyze the acylation of the XclA-derived initial xenocyloins with acetyl-, propionyl-, or malonyl-CoA, thereby resulting in the formation of further xenocyloin derivatives. All xenocyloins were produced mainly by the more virulent primary variant of X. bovienii and showed activity against insect hemocytes thus contributing to the overall virulence of X. bovienii against insects., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Pharmacophores describe the spatial arrangement of essential interactions in a receptor-ligand complex. Although highly established in ligand-based virtual screening, the application of pharmacophores for in absence of a ligand is more sophisticated. This article summarizes the recent approaches to derive and evaluate pharmacophore models using only limited information (e.g. a homology model of the binding site). A range of different methodologies including geometrical and/or potential-based methods and successes in the application to virtual screening problems are described. Advantages and current limitations of the state-of-the-art methods and future perspectives for development are discussed in this publication., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)