A mild and general route for preparing pyridines from nitriles and diynes is described. Ni/imidazolyidene complexes were used to mediate cyclization alkynes and both aryl and alkyl nitriles at ambient temperature. In addition, the efficacy of this protocol allows for the preparation of a fused seven-membered pyridone and for intermolecular cyclizations. When an asymmetrical diyne was employed, cyclization afforded a single pyridine regioisomer.

The bleomycins (BLMs) are structurally related glycopeptide antibiotics isolated from Streptomyces verticillus that mediate the sequence-selective oxidative damage of DNA and RNA. Deglycobleomycin, which lacks the carbohydrate moiety, cleaves DNA analogously to bleomycin itself, albeit less potently, and has been used successfully for analyzing the functional domains of bleomycin. Although structural modifications to bleomycin and deglycobleomycin have been reported, no bleomycin or deglycobleomycin analogue having enhanced DNA cleavage activity has yet been described. The successful synthesis of a deglycobleomycin on a solid support has permitted the facile solid-phase synthesis of 108 unique deglycobleomycin analogues through parallel solid-phase synthesis. Each of the deglycobleomycin analogues was synthesized efficiently; the purity of each crude product was greater than 60%, as determined by HPLC integration. The solid-phase synthesis of the deglycobleomycin library provided near-milligram to milligram quantities of each deglycobleomycin, thereby permitting characterization by (1)H NMR and high-resolution mass spectrometry. Each analogue demonstrated supercoiled plasmid DNA relaxation above background cleavage; the library included two analogues that mediated plasmid relaxation to a greater extent than the parent deglycobleomycin molecule.

In many jurisdictions, public safety and public health entities are working together to enhance the timeliness and accuracy of the analytical characterization and toxicology testing of novel synthetic opioids. The improved sharing and early detection of these analytical data are intended to inform surveillance, interdiction efforts, patient intervention and treatment, all of which are critical to curbing the opioid epidemic. Forensic practitioners working to identify novel synthetic opioids struggle to provide timely results when encountering new or unknown substances, such as the fentanyl analogs. These compounds, which mimic heroin in pharmacologic effect but can be far more potent, are inconsistently present in chemical identification libraries, and are currently largely unavailable as reference materials for analytical comparison. Additionally, federal, state and local governments as well as nongovernmental organizations require potency, toxicity and potential-for-abuse data to evaluate the potential health risks of emerging drug threats. Subsequent scheduling efforts and criminal prosecutions also require these thorough drug characterization studies. Pilot programs have demonstrated that early communication of real-time drug toxicity and analytical data significantly impacts the successful response to emerging opioids. High-quality, real-time, national-level data on chemical composition, toxicological test data, drug toxicity and overdoses, and analysis of seized materials by law enforcement are needed to track drug trends. However, the USA still lacks a national system to coordinate and communicate toxicology, medical and medical examiner and coroner data with the broader medical and law enforcement communities. Opportunities to address these gaps as well as recent advancements collected through interagency efforts and technical workshops in the toxicology and analytical chemistry communities are presented here. Opportunities for partnership, increased communication and expanding best practices to move toward an integrated, holistic analytical response are also explored.

Chromatography has been a fundamental technique used for chemical separation that dates back to the 1850s. Specifically, column chromatography, typically taught in introductory organic chemistry laboratories, traditionally involves the use of halogenated or harmful solvents, which novice students often overuse. This situation runs contrary to the principles of responsible chemical and waste management emphasized by the green chemistry movement. Since this movement began, conventional means of separation using harmful solvents have been modified to emphasize the need for safer, less hazardous materials and the generation of such waste. The current experiment emphasizes the green chemical principles of renewable feedstocks and recycling to minimize waste, while simultaneously introducing or reinforcing common organic techniques, including solvent extraction, column chromatography, and thinlayer chromatography for the isolation and identification of photosynthetic pigments from spinach leaves. Students gain practical experience processing plant material to isolate and identify the pigments, β-carotene, xanthophylls, and chlorophyll a, using the solvents hexane and acetone. This experiment was designed for use as a standalone single-session lab or, alternatively, it can be coupled with an experiment to recycle waste acetone to further emphasize sustainable practices.

The bleomycin (BLM) group of antitumor antibiotics effects DNA cleavage in a sequence-selective manner. Previous studies have indicated that the metal-binding and bithiazole moieties of BLM are both involved in the binding of BLM to DNA. The metal-binding domain is normally the predominant structural element in determining the sequence selectivity of DNA binding, but it has been shown that replacement of the bithiazole moiety with a strong DNA binder can alter the sequence selectivity of DNA binding and cleavage. To further explore the mechanism by which BLM and DNA interact, a trithiazole-containing deglycoBLM analogue was synthesized and tested for its ability to relax supercoiled DNA and cleave linear duplex DNA in a sequence-selective fashion. Also studied was cleavage of a novel RNA substrate. Solid-phase synthesis of the trithiazole deglycoBLM A(5) analogue was achieved using a TentaGel resin containing a Dde linker and elaborated from five key intermediates. The ability of the resulting BLM analogue to relax supercoiled DNA was largely unaffected by introduction of the additional thiazole moiety. Remarkably, while no new sites of DNA cleavage were observed for this analogue, there was a strong preference for cleavage at two 5'-GT-3' sites when a 5'-(32)P end-labeled DNA duplex was used as a substrate. The alteration of sequence selectivity of cleavage was accompanied by some decrease in the potency of DNA cleavage, albeit without a dramatic diminution. In common with BLM, the trithiazole analogue of deglycoBLM A(5) effected both hydrolytic cleavage of RNA in the absence of added metal ion and oxidative cleavage in the presence of Fe(2+) and O(2). In comparison with BLM A(5), the relative efficiencies of hydrolytic cleavage at individual sites were altered.