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As of October 2022, the United Nations Office on Drugs and Crime (UNODC) Early Warning Advisory (EWA) has monitored over 1 150 new psychoactive substances (NPS) that had appeared in 137 countries and territories, including 76 substances that were notified for the first time in 2022. The increasing popularity of NPS has become a policy challenge and a major international concern, and poses potential risks for public health. Ketamine and ketamine analogues belong to β-keto-arylcyclohexylamines, which are classified into dissociative NPS due to their “dissociative anesthetic” effect. According to the monitoring data of the National Narcotics Laboratory, as of August 2022, ten ketamine structural analogues have been detected in China, including 2-(2-chlorophenyl)-2-(ethylamino) cyclohexan-1-one (NENK), 2-(3-methoxyphenyl)-2-(ethylamino) cyclohexan-1-one (MXE), 2-phenyl-2-(methylamino) cyclohexan-1-one (DCK), and 2-(2-fluorophenyl)-2-(methylamino)cyclohexan-1-one (2-FDCK), 2-(ethylamino)-2-phenylcyclohexan-1-one (2-oxo-PCE), 2-(methylamino)-2-(2-methylphenyl)cyclohexan-1-one (2-MDCK), 2-(ethylamino)-2-(2-fluorophenyl)cyclohexan-1-one (2-FXE), 2-(2-bromophenyl)-2-(methylamino)cyclohexan-1-one (2-BDCK), and 2-(ethylamino)-2-(thiophen-2-yl)cyclohexan-1-one (tiletamine), and 2-(ethylamino)-2-(2-methylphenyl)cyclohexan-1-one (deoxymethoxetamine). According to the structures, these compounds can be seen as structural analogues of ketamine with benzene ring replaced by fluorine, bromine, methyl and methoxy groups, or with methyl group on the nitrogen atom replaced by ethyl group, or with benzene ring replaced by furan group. NENK, MXE, DCK and 2-FDCK have already been included in the annexes of the law in China, while 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine have not been listed in the regulation. In order to evade the supervision of the law, new types of ketamine analogues have been continuously produced and offered for sale on the NPS market. These emerging new compounds have posed a great challenge to the testing and identification ability of forensic science laboratories around the world. The knowledge of MS fragmentation pathway characteristics of known structure NPS is essential for the structure elucidation of new types of NPS. In order to investigate the mass fragmentation characteristics of ketamine analogues, NENK, MXE, DCK, 2-FDCK, 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine were analyzed using gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap-MS) and ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-QTOF-MS). High-resolution mass spectra were obtained by electron impact (EI) and electrospray ionization collision-induced dissociation (ESI-CID), the structures and fragmentation pathways of main ions were deduced. The product ions of ketamine analogues were mainly formed by the loss of CO, C2H5·, C3H7·, C4H9·, C5H11·/C6H13· in EI mode, and were mainly formed by the loss of H2O, CH3NH2/C2H5NH2, CO, C4H6, C2H4O in ESI-CID mode. The ketamine analogues distinguishing features were summarized by investigating the high-resolution mass spectrometric characteristics, which can provide a reference for the identification of new ketamine analogues with similar chemical structures. [ABSTRACT FROM AUTHOR]

In the present study, the occurrence and distribution of methylsiloxanes (D4-D6, L5-L16) in the surface water and sediment collected from the Daqing oilfield were explored. For wastewater samples from an oilfield combination station, the concentrations of total cyclic methylsiloxanes (∑CMS, D4-D6) and total linear methylsiloxanes (∑LMS, L5-L16) ranged from 137–1911 ng/L to 49.4–190 ng/L, respectively. Cyclic methylsiloxanes were the predominant methylsiloxanes in the analyzed wastewater samples from the oilfield combination station. In addition, methylsiloxanes were detected in the surface water from three sampling areas, and the total concentrations varied from

Biodegradation usually masks or even radically alters the original characteristics of molecular biomarkers, restricting the oil sources identification and the exploration of ultra-heavy oils (also known as oil sands, tar sands, asphalt or bitumen). The oils from the Lower Neogene Shawan Formation (N 1 s), Lower Cretaceous Tugulu Group (K 1 tg), and Upper Carboniferous Xibeikulasi Formation (C 2 x) in the Chepaizi Uplift, Junggar Basin (NW China) were biodegraded to different extent, consequently, many commonly used biomarker parameters became less powerful for the evaluation of the extent of biodegradation. To address this problem, the resistance of many adamantane and diamantane homologs and carboxylic acids to biodegradation was analyzed, and those with high bioresistance were selected to yield a more precise and extensive characterization of biodegradation from light to extreme. In contrast, oils from the eastern Chepaizi Uplift were generated from Permian sources, and have been subjected to heavy to extreme levels of biodegradation. In this study, fifteen oil samples obtained from the Chepaizi Uplift were analyzed by a set of mass spectrometric techniques. The results were applied to investigate the variations of commonly used biomarkers in the saturates and aromatics, to qualitatively rank oil biodegradation levels based on the PM scale and to provide a detailed assessment of the variation in carboxylic acids and adamantane and diamantane homologs in heavy oils from varying degrees of biodegradation. The results demonstrate that adamantane and diamantane homologs with various methyl groups, and carboxylic acids with various double bond equivalents (DBEs), exhibit an intact homolog series distribution and certain hypermethylation trend as biodegradation levels progress from light to extreme, which confirmed their reliability in refining the evaluation scale and characterizing the extent of biodegradation. In addition, the full-range biodegradation index (FRBI) presented here consists of the ratios of adamantane/diamantane homologs with different numbers of methyl substituents and the ratios of carboxylic acids with different DBE values, instead of the five Manco scores of 0–4 used previously, which can effectively improve the ranking precision of biodegradation of oils between subtle alteration changes, and universally unraveling to the full range of biodegradation, beginning from light to extreme. • Adamantane homologs and carboxylic acids are detected in lightly-extremely biodegraded oils. • Biodegradation proxies of adamantane homologs and carboxylic acids were proposed. • Ratios were used to refine the biodegradation evaluation score instead of the five Manco scores of 0–4. [ABSTRACT FROM AUTHOR]

Studies have shown that some cyclic methyl siloxanes were identified as characterized of persistent, bioaccumulated, toxic, and potential to ecological harm. In this study, we determined methyl siloxanes in seawater, sediment and bottom fish samples collected from marine environment in Northeast China. The mean concentrations of total methyl siloxanes were 46.1 ± 27.2 ng/L, 12.4 ± 5.39 ng/g dry weight (dw) and 5.10 ± 1.34 wet weight (ww) in seawater, sediment and fish, respectively. Very strong and significant correlations (r = 0.94, p < 0.0001) were found in compositions of methyl siloxanes between seawater and sewage, indicating that sewage was the main source of methyl siloxanes in the marine area studied. It was found that the mean value of biota-sediment accumulation factor (BSAF) was.0.716 ± 0.456 for D4, 0.103 ± 0.0771 for D5, 1.06 ± 0.528 for D6 and 0.877 ± 0.530 for D7. [Copyright &y& Elsevier]

A partial syntheses of the biologically active 23-hydroxybetulonic acid and 23-hydroxybetulinic acid starting from the naturally abundant betulinic acid has been developed in which the key step was the Baldwin's cyclopalladation of the 23-methyl group from a 3-one oxime of betulinic acid, an important drug in Chinese medicine. [ABSTRACT FROM AUTHOR]

Physalins, including physalins and neophysalins, are a class of highly oxygenated ergostane-type steroids. They are commonly known by the name of 16,24- cyclo -13,14- seco steroids, in which the disconnection of C-13 and C-14 produces an eight or nine-membered ring and the carbocyclization of C-16 and C-24 generates a new six-membered ring. Meanwhile, the oxidation of C-18 methyl to carboxyl group forms a 18,20-lactone, and the oxidation of C-14 and C-17 gets a heterocyclic oxygen acrossing rings C and D. Additionly, physalins frequently form an oxygen bridge to connect C-14 to C-27. Physalins are a kind of characteristic constituents from the species of the genus Physalis (Solanaceae), which are reported with a wide array of pharmacological activities, including anticancer, anti-inflammatory, immunoregulatory, antimicrobial, trypanocidal and leishmanicidal, antinociceptive, antidiabetic and some other activities. Herein,the research progress of physalins from the genus Physalis during the decade from 1970 to 2021 on phytochemistry, pharmacology, pharmacokinetics and application in China are systematically presented and discussed for the first time. [Display omitted] • Physalins act as the primary chemical constituents of the genus Physalis. • A total of 78 physalins with extensive pharmacological activities have been isolated from genus Physalis until now. • The research progress of physalins from the genus Physalis during the decade from 1970 to 2021 are summarized. [ABSTRACT FROM AUTHOR]

A new cucurbitacin, endecaphyllacin C, was isolated from the tubers of Hemsleya endecaphylla. The structure was elucidated as 2β,16α,20β,25-tetrahydroxy-24-acetylaminocucurbita-5-en-3,11,22-trione ( 1) on the basis of extensive 1D and 2D NMR techniques, including COSY, HMBC, HMQC, and NOESY correlations, as well as HR-FAB-MS analysis. [ABSTRACT FROM AUTHOR]

The article provides information on the evolution of the distinctive scent of Chinese roses. Unlike their European counterparts, the main scent component of Chinese roses and their descendants is dimethoxytoluene. In the final steps of its formation, two methyl groups are sequentially added to a precursor molecule in reactions catalysed by enzymes called OOMT1 and OOMT2. These enzymes are almost identical in amino-acid sequence, yet they target different substrates. The authors' further phylogenetic analysis strongly hints that, in Chinese species, the second OOMT gene arose through a duplication event.