Increasing the versatility of the biphenyl-fused-dioxacyclodecyne class of strained alkynes.

Biphenyl-fused-dioxacyclodecynes are a promising class of strained alkyne for use in Cu-free 'click' reactions. In this paper, a series of functionalised derivatives of this class of reagent, containing fluorescent groups, are described. Studies aimed at understanding and increasing the reactivity of the alkynes are also presented, together with an investigation of the bioconjugation of the reagents with an azide-labelled protein.

Interference of the novel designer benzodiazepine 4'-chloro deschloroalprazolam with alprazolam analysis in toxicology and seized drug DUID casework.

In recent years, the emergence of the novel designer benzodiazepine 4'-chloro deschloroalprazolam has presented a new challenge for forensic laboratories by interfering with the identification and quantitation of alprazolam. As an isomer of alprazolam, 4'-chloro deschloroalprazolam has similar physicochemical properties and can be misidentified in casework samples as alprazolam without a specific method to differentiate the two analytes. Starting in late 2021, the Houston Forensic Science Center (HFSC) received toxicological and seized drug evidence indicating the presence of 4'-chloro deschloroalprazolam. An interference study was performed to supplement the laboratory's validated benzodiazepines method for toxicological samples to differentiate alprazolam from 4'-chloro deschloroalprazolam. This study showed that while the isomers could not be chromatographically resolved using the current method, they could be differentiated based on their retention times relative to the internal standard, alprazolam-d5. Based on these findings, the HFSC toxicology laboratory reports test results as "unsuitable for analysis due to an interference" if a suspected alprazolam peak elutes before the alprazolam-d5 peak, even if all identification and quantification criteria (e.g., retention time) were acceptable. Additionally, the seized drug and toxicology laboratories re-evaluated previously analyzed alprazolam-positive casework to determine if suspected 4'-chloro deschloroalprazolam had been misidentified as alprazolam. This report presents three cases: one case with toxicological evidence indicating the presence of both 4'-chloro deschloroalprazolam and alprazolam, and two cases with both seized drug material and toxicology evidence indicating the presence of 4'chloro deschloroalprazolam with no detected alprazolam.

An Enhanced LC-MS-MS Technique for Distinguishing Δ8- and Δ9-Tetrahydrocannabinol Isomers in Blood and Urine Specimens.

Among the abundance of cannabinoids identified in cannabis, the active parent drug, Δ9-tetrahydrocannabinol (Δ9-THC), and its oxidized metabolite, 11-nor-9-carboxy-Δ9-THC (Δ9-THCCOOH), are attractive analytical targets to detect cannabis use. More recently, confirmation of these analytes may be hindered by a related interfering compound. Forensic toxicology laboratories attribute this phenomenon to an increase in cases containing Δ8-tetrahydrocannabinol (Δ8-THC) and 11-nor-9-carboxy-Δ8-THC (Δ8-THCCOOH). It is technically challenging to chromatographically resolve and accurately quantify Δ8- and Δ9-THC and THCCOOH in toxicology specimens due to their structural resemblance. This study describes a validated method to resolve and quantify active Δ8-THC and Δ9-THC in blood while qualitatively confirming the inactive metabolites Δ8-THCCOOH and Δ9-THCCOOH in blood and urine. Analytes are extracted and concentrated by solid-phase extraction and analyzed by liquid chromatography--electrospray ionization tandem mass spectrometry, which is amenable to modern toxicology laboratory routine workflows. This procedure offers a clear solution to untangling mixtures of these isomers, particularly in cases where Δ8-THC and its metabolite are the sole or dominant form.

Screening and confirmation methods for the qualitative identification of nine phytocannabinoids in urine by LC-MS/MS.

Qualitative liquid chromatography tandem mass spectrometry (LC-MS/MS) methods were developed and validated to screen and confirm the presence of nine phytocannabinoids in urine. The nine phytocannabinoids targeted in the methods included Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC, cannabidiol, 7-carboxy cannabidiol, cannabinol, cannabigerol, Δ9-tetrahydrocannabivarin (THCV), and 11-nor-9-carboxy-THCV. The methods presented use a rapid, single-step enzymatic hydrolysis followed by solid-phase extraction and LC-MS/MS analysis. Limits of detection were established at 1 µg/L for non-carboxylated analytes and 5 µg/L for carboxylated analytes. The screening and confirmation methods were validated and implemented in the analysis of authentic case samples. These methods can assist forensic, medicolegal, or medical compliance investigations as the presence of phytocannabinoids, or lack there-of, may be used to help differentiate cannabis (hemp, marijuana) use from synthetic THC (dronabinol) exposure.

A strained alkyne-containing bipyridine reagent; synthesis, reactivity and fluorescence properties.

We report the synthesis of a bipyridyl reagent containing a strained alkyne, which significantly restricts its flexibility. Upon strain-promoted alkyne-azide cycloaddition (SPAAC) with an azide, which does not require a Cu catalyst, the structure becomes significantly more flexible and an increase in fluorescence is observed. Upon addition of Zn(ii), the fluorescence is enhanced further. The reagent has the potential to act as a fluorescent labelling agent with azide-containing substrates, including biological molecules.