10. Patented Literature 2616 10.1. Esterification 2616 10.2. Ether Formation 2619 10.2.1. Etherification without Cyclization 2619 10.2.2. Etherification with Cyclization 2624 10.3. N-Alkylation 2625 10.4. Other Reactions 2627 11. Summary and Outlook 2628 12. Note Added in Proof 2628 13. Abbreviations Used in This Review 2629 14. Acknowledgments 2629 15. Supporting Information Available 2630 16. References 2630

Mitsunobu and Related Reactions: Advances and Applications

Biology and chemistry of endophytes.

Summary: Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed.

Nitroaromatic Compounds, from Synthesis to Biodegradation

https://pubs.rsc.org/en/Content/ArticlePDF/2016/NP/C6NP00074F

Phytocannabinoids: a unified critical inventory.

The field of total synthesis has a rich history and a vibrant future. Landmark advances and revolutionary strides in the logic of synthesis have put the practicing chemist in the enviable position of being able to create nearly any molecule with enough time and effort. The stage is now set for organic chemists to aim for "ideality" in the way molecules are synthesized. This perspective presents a simple and informative definition of "ideality" and demonstrates its use during the self-evaluation of several syntheses from our laboratory.

Aiming for the Ideal Synthesis

Monorden (1) and the novel resorcylic acid lactones pochonins A (2), B (4), C (6), D (7), and E (8) as well as tetrahydromonorden (5) and pseurotin A (22) were isolated from cultures of the clavicipitaceous hyphomycete Pochonia chlamydosporia var. catenulata strain P 0297. Fermentation of P 0297 in bromide-containing culture media led to a shift in secondary metabolite production and yielded monocillins III (3) and II (9) as major metabolites besides monorden (1) as well as the novel compounds pochonin F (10) and a monocillin II glycoside (11) as minor metabolites. Most of these compounds showed moderate activities in a cellular replication assay against Herpes Simplex Virus 1 (HSV1) and against the parasitic protozoan Eimeria tenella. In contrast to the structurally related zearalenone derivatives none of the metabolites of strain P 0297 were found to be active in a fluorescence polarization assay for determination of modulatory activities on the human estrogenic receptor ERβ. β-Zearalenol (17), but not ...

Pochonins A-F, new antiviral and antiparasitic resorcylic acid lactones from Pochonia chlamydosporia var. catenulata.

A novel antibacterial antibiotic, for which the name altersetin is proposed, was isolated from the culture broth of two endophytic Alternaria species. The relative and absolute configuration were assigned by NOESY or CD data, respectively. Altersetin is chemically related to equisetin and showed potent MIC against several pathogenic Gram-positive bacteria, whereas Gram-negative bacteria and pathogenic yeast were not or much less susceptible. Moderate in vivo efficiacy was observed for altersetin in a murine sepsis model.

/pdf/altersetin-a-new-antibiotic-from-cultures-of-endophytic-35ju4i9t8w.pdf

Altersetin, a new antibiotic from cultures of endophytic Alternaria spp. Taxonomy, fermentation, isolation, structure elucidation and biological activities.

The Xylariaceae are among the best-investigated filamentous fungi with regard to the production of secondary metabolites. Numerous reports on biologically active compounds with potential for application in human and veterinary medicine or as crop protection agents revealed this family of ascomycetes to be one of the hotspots of molecular diversity. Moreover, the secondary metabolites themselves appear to be very useful for the taxonomic classification of their producers. Most morphological traits and even the results of recent studies on the molecular phylogeny of these fungi based on cladistic analyses of ribosomal gene DNA sequences basically agreed with the distribution of characteristic secondary metabolites. The review gives an overview on unique, bioactive, and taxonomically significant metabolites of Xylariaceae, summarises current knowledge on their chemotaxonomy and also deals with the bioactive compounds produced at other members of the order Xylariales. Hence, the advantage of combining taxonomic knowledge with state of the art analytical and microbiological methods to increase the chances for bioprospecting in modern drug discovery over a random approach is emphasised.

Chemotaxonomy of the Xylariaceae and remarkable bioactive compounds from Xylariales and their associated asexual stages

Cohaerins A and B, azaphilones from the fungus Hypoxylon cohaerens, and comparison of HPLC-based metabolite profiles in Hypoxylon sect. Annulata.

Natural products are an indispensable source for drug discovery The major challenge for exploiting this evolutionary optimized pool of potential lead structures is the fast and reliable recognition of known compounds, ie dereplication This task is essential for the discovery process in high-throughput screening scenarios, since it allows the focus to be placed on novel chemical structures at an early stage Furthermore, information on identified compounds will help to rationalize observed bioactivities This article describes an effective, library-supported strategy for the dereplication of crude extracts and pre-fractionated samples, using an HPLC-based multidetector platform and NMR techniques, respectively

Veronika Hellwig

Papers

Pochonins A-F, new antiviral and antiparasitic resorcylic acid lactones from Pochonia chlamydosporia var. catenulata.

Altersetin, a new antibiotic from cultures of endophytic Alternaria spp. Taxonomy, fermentation, isolation, structure elucidation and biological activities.

Chemotaxonomy of the Xylariaceae and remarkable bioactive compounds from Xylariales and their associated asexual stages

Cohaerins A and B, azaphilones from the fungus Hypoxylon cohaerens, and comparison of HPLC-based metabolite profiles in Hypoxylon sect. Annulata.

Accelerated dereplication of natural products, supported by reference libraries