Philippe Bisel

Identification of the cannabimimetic AM-1220 and its azepane isomer (N-methylazepan-3-yl)-3-(1-naphthoyl)indole in a research chemical and several herbal mixtures

Recently, a large number of synthetic cannabinoids have been identified in herbal mixtures. Moreover, an even higher number of cannabimimetic compounds are currently distributed as research chemicals on a gram to kilogram scale via several online trading platforms. As this situation leads to a large number of new cannabimimetics and the occurrence of isobaric substances, the analysis of such compounds using mass spectroscopy (MS) involves the risk of incorrect assignments of mass spectra. In certain cases, this leads to considerable analytical challenges. In the majority of cases, these challenges can only be mastered by combining multiple analytical techniques. We purchased a so-called research chemical advertised as the cannabimimetic compound [(N-methylpiperidin-2-yl)methyl]-3-(1-naphthoyl)indole (AM-1220) via an Internet platform. Analysis of the microcrystalline substance using gas chromatography (GC)–MS indicated the presence of pure AM-1220. However, after further purity testing utilizing thin-layer chromatography we were surprised to see an additional spot indicating a mixture of two substances with highly similar physicochemical properties. After isolation, high-resolution mass spectroscopy (HR-MS) revealed an elemental composition of C26H26N2O for both substances, proving the presence of two isobaric substances. Moreover, GC–MS and LC-HR-MS/MS experiments indicated two naphthoylindoles featuring different heterocyclic substituents at the indole nitrogen. Nuclear magnetic resonance spectroscopy verified the presence of the highly potent cannabimimetic AM-1220 and its azepane isomer. Interestingly, only a few weeks after purchasing the powder we also detected both substances in a similar proportion in several herbal mixtures for the first time.

Characterization of the four designer benzodiazepines clonazolam, deschloroetizolam, flubromazolam, and meclonazepam, and identification of their in vitro metabolites

In 2012, the first designer benzodiazepines were offered in Internet shops as an alternative to prescription-only benzodiazepines. Soon after these compounds were scheduled in different countries, new substances such as clonazolam, deschloroetizolam, flubromazolam, and meclonazepam started to emerge. This article presents the characterization of these four designer benzodiazepines using nuclear magnetic resonance spectroscopy, gas chromatography–electron ionization-mass spectrometry, liquid chromatography–tandem mass spectrometry, liquid chromatography–quadrupole time-of-flight-mass spectrometry, and infrared spectroscopy. The major in vitro phase I metabolites of the substances were investigated using human liver microsomes. At least one monohydroxylated metabolite was identified for each compound. Dihydroxylated metabolites were found for deschloroetizolam and flubromazolam. For clonazolam and meclonazepam, signals at mass-to-charge ratios corresponding to the reduction of the nitro group to an amine were observed. Desalkylations, dehalogenations, or carboxylations were not observed for any of the compounds investigated. Furthermore, for clonazolam and meclonazepam, no metabolites formed by a combination of reduction and mono-/dihydroxylation were detected. This knowledge will help to analyze these drugs in biological samples.

Carbocyclic α,β-diamino acids: asymmetric Strecker synthesis of stereomeric 1,2-diaminocyclohexanecarboxylic acids

Abstract Asymmetric syntheses of trans- ( R , R )- and ( S , S )-1,2-diaminocyclohexanecarboxylic acids have been achieved with ee >99% while the respective cis -( R , S )- and ( S , R )-stereoisomers were obtained as 1-amino-2-benzoylaminocyclohexanecarboxylic acids. The underlying second generation asymmetric synthesis proceeds via Strecker reaction with commercially available ( R )- and ( S )-1-phenylethylamine (1-PEA) as chiral auxiliaries, TMSCN as cyanide source and racemic 2-benzoylaminocyclohexanone. The key stereodifferentiating step of the cyanide addition to the chiral ketimine intermediates has been studied under the influence of protic and aprotic solvents. Hydrolysis of the nitriles to the carboxamides with conc. H 2 SO 4 yielded dramatic changes in the product composition as a function of temperature and time. Hydrolysis of both the attendant amido groups are concomitant processes in case of the trans -configured carboxamides while the cis -stereoisomers undergo selective carboxamide hydrolysis, with the benzoyl protecting group remaining intact, leading to orthogonally protected α,β-diamino acids. The absolute configurations of the amino acids and their intermediates have been assigned based on detailed NMR spectroscopic analysis and X-ray data.

Diastereo‐ and Enantioselective Synthesis of (+)‐ and (−)‐cis‐2‐Aminocyclobutanols

The hitherto unknown (+)- and (−)-cis-2-aminocyclobutanols 6a,b and 7a,b, as well as the corresponding benzyloxycyclobutanamines 8a,b, have been synthesized by means of asymmetric reductive amination, with de values of 100% and ee values ranging from 96.9 to 99.8%. The relative cis configuration has been established by NO experiments, whereas the absolute stereochemistry has been deduced from the CD spectra of the corresponding salicylidene derivatives and confirms the like induction at C-1.

Functions of Genes and Enzymes Involved in Phenalinolactone Biosynthesis

Phenalinolactones are novel terpene glycoside antibiotics produced by Streptomyces sp. Tü6071. Inactivation of three oxygenase genes (plaO2, plaO3 and plaO5), two dehydrogenase genes (plaU, plaZ) and one putative acetyltransferase gene (plaV) led to the production of novel phenalinolactone derivatives (PL HS6, PL HS7, PL HS2 and PL X1). Furthermore, the exact biosynthetic functions of two enzymes were determined, and their in vitro activities were demonstrated. PlaO1, an FeII/α‐ketoglutarate‐dependent dioxygenase, is responsible for the key step in γ‐butyrolactone formation, whereas PlaO5, a cytochrome P450‐dependent monooxygenase, catalyses the 1‐C‐hydroxylation of phenalinolactone D. In addition, stable isotope feeding experiments with biosynthetic precursors shed light on the origin of the carbons in the γ‐butyrolactone moiety.

Diastereoselective α-iminoamine rearrangement: asymmetric synthesis of (R)-(−)- and (S)-(+)-2-benzyl-2-hydroxycyclohexanone

Abstract A convenient asymmetric synthesis of both (R)-(−)- and (S)-(+)-2-benzyl-2-hydroxycyclohexanones starting from racemic 2-benzyloxycyclohexanone and the chiral auxiliary 1-phenylethylamine is reported. The route involves a [1,3]-sigmatropic shift and a new diastereoselective α-iminoamine rearrangement of a 2-benzyl-2-iminocyclohexanamine substrate.

Expeditious synthesis and chromatographic resolution of (+)- and (-)-trans-1-benzylcyclohexan-1,2-diamine hydrochlorides.

The hitherto unknown (-)- and (+)-1-benzylcyclohexan-1,2-diamine hydrochlorides 4a. HCl and 4b. HCl were synthesized by means of diastereoselective alpha-iminoamine rearrangement with subsequent imine reduction and hydrogenolysis. The relative trans-configuration as well as the absolute (1S,2R) and (1R,2S) configurations of 4a and 4b, respectively, were elucidated on the basis of an X-ray analysis of 3b. HCl. The enantiomeric excess (ee) values of the title compounds (>99%) were determined by chiral HPLC on a Chirex (D) Penicillamine column.

Wide Distribution of Foxicin Biosynthetic Gene Clusters in Streptomyces Strains – An Unusual Secondary Metabolite with Various Properties

Streptomyces diastatochromogenes Tü6028 is known to produce the polyketide antibiotic polyketomycin. The deletion of the pokOIV oxygenase gene led to a non-polyketomycin-producing mutant. Instead, novel compounds were produced by the mutant, which have not been detected before in the wild type strain. Four different compounds were identified and named foxicins A–D. Foxicin A was isolated and its structure was elucidated as an unusual nitrogen-containing quinone derivative using various spectroscopic methods. Through genome mining, the foxicin biosynthetic gene cluster was identified in the draft genome sequence of S. diastatochromogenes. The cluster spans 57 kb and encodes three PKS type I modules, one NRPS module and 41 additional enzymes. A foxBII gene-inactivated mutant of S. diastatochromogenes Tü6028 ΔpokOIV is unable to produce foxicins. Homologous fox biosynthetic gene clusters were found in more than 20 additional Streptomyces strains, overall in about 2.6% of all sequenced Streptomyces genomes. However, the production of foxicin-like compounds in these strains has never been described indicating that the clusters are expressed at a very low level or are silent under fermentation conditions. Foxicin A acts as a siderophore through interacting with ferric ions. Furthermore, it is a weak inhibitor of the Escherichia coli aerobic respiratory chain and shows moderate antibiotic activity. The wide distribution of the cluster and the various properties of the compound indicate a major role of foxicins in Streptomyces strains.

A Novel Approach to the Rare 4- and 5-Alkylindan-2-ols

The rare 4- and 5-alkylindan-2-ols have been synthesized in 62–72% yields by formal 1,6- and 1,4-nucleophilic ring opening of the 2-hydroxyindan 3a,7a-oxide, respectively.