A fast and inexpensive procedure for the isolation of synthetic cannabinoids from 'Spice' products using a flash chromatography system.

In the age of the Internet, the variety of drugs offered online is constantly increasing, and new drugs emerge every month. One group of drugs showing such an enormous increase is that of synthetic cannabinoids. Since their first identification in 'herbal mixtures', new structural modifications continue to appear on the market. In order to keep up with this process, toxicological screening methods need to be up to date. This can become extremely difficult if no reference material is available. In this article, a fast and effective way to extract and purify synthetic cannabinoids from 'herbal mixtures' is presented. This method opens a new opportunity for a timely reaction by obtaining reference material straight out of the 'herbal mixtures' ordered via the Internet. Isolation was carried out on a flash chromatography system with gradient elution on a C18 column using methanol and 0.55 % formic acid as mobile phases. The obtained purity of all compounds exceeded 99 %. In addition to the isolation of single compounds, the method proved to be suitable for the separation of various synthetic cannabinoids in one mixture, including the diastereomers cis- and trans-CP-47,497-C8. This approach for obtaining pure standards of new drugs proved to be effective, inexpensive and much quicker than waiting for the substances to be commercially available as reference material.

α-Hydroxy-ß-keto acid rearrangement-decarboxylation: impact on thiamine diphosphate-dependent enzymatic transformations.

The thiamine diphosphate (ThDP) dependent MenD catalyzes the reaction of α-ketoglutarate with pyruvate to selectively form 4-hydroxy-5-oxohexanoic acid 2, which seems to be inconsistent with the assumed acyl donor role of the physiological substrate α-KG. In contrast the reaction of α-ketoglutarate with acetaldehyde gives exclusively the expected 5-hydroxy-4-oxo regioisomer 1. These reactions were studied by NMR and CD spectroscopy, which revealed that with pyruvate the observed regioselectivity is due to the rearrangement-decarboxylation of the initially formed α-hydroxy-ß-keto acid rather than a donor-acceptor substrate role variation. Further experiments with other ThDP-dependent enzymes, YerE, SucA, and CDH, verified that this degenerate decarboxylation can be linked to the reduced enantioselectivity of acyloins often observed in ThDP-dependent enzymatic transformations.

Identification and structural characterization of the synthetic cannabinoid 3-(1-adamantoyl)-1-pentylindole as an additive in 'herbal incense'.

Since the end of 2010, more than 20 synthetic cannabimimetics have been identified in 'Spice' products, demonstrating the enormous dynamic in this field. In an effort to cope with the problem, many countries have already undertaken legal measures by putting some of these compounds under control. Nevertheless, once a number of compounds were scheduled, they were soon replaced by other synthetic cannabinoids. In this article, we report the identification of a new--and due to its substitution pattern rather uncommon--cannabimimetic found in several 'herbal incense' products. The GC-EI mass spectrum first led to misidentification as the alpha-methyl-derivative of JWH-250. However, since both substances show different retention indices, thin-layer chromatography was used to isolate the unknown compound. After application of nuclear magnetic resonance spectroscopy, high-resolution MS and GC-MS/MS techniques, the compound was identified as 3-(1-adamantoyl)-1-pentylindole, a derivative of JWH-018 carrying an adamantoyl moiety instead of a naphthoyl group. This finding supports that the listing of synthetic cannabinoids as prohibited substances triggers the appearance of compounds with uncommon substituents. Moreover, it emphasizes the necessity of being aware of the risk of misidentification when using techniques sometimes providing only limited structural information like GC-MS.

Separation and structural characterization of the synthetic cannabinoids JWH-412 and 1-[(5-fluoropentyl)-1H-indol-3yl]-(4-methylnaphthalen-1-yl)methanone using GC-MS, NMR analysis and a flash chromatography system.

The 'herbal highs' market continues to boom. The added synthetic cannabinoids are often exchanged for another one with a high frequency to stay at least one step ahead of legal restrictions. While most of these substances were synthesized for pharmaceutical purposes and have been described in the scientific literature before, others originate from clandestine laboratories supplying this lucrative market. In this paper, the identification and structure elucidation of two synthetic cannabinoids is reported. The first compound, 1-[(5-fluoropentyl)-1H-indol-3yl]-(4-methylnaphthalen-1-yl)methanone, was found along with AM-2201 in a 'herbal mixture' obtained via the Internet. For isolation of the substance from the mixture, a newly developed flash chromatography method was used providing an inexpensive and fast way to gain pure reference substances from 'Spice' products for the timely development or enhancement of analytical methods in the forensic field. The second substance, 4-fluoronaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-412) was seized by German authorities as microcrystalline powder, making it very likely that it will be found in 'herbal mixtures' soon.

Chirality and diastereoselection of Δ/Λ-configured tetrahedral zinc complexes through enantiopure Schiff base complexes: combined vibrational circular dichroism, density functional theory, 1H NMR, and X-ray structural studies.

The metal-centered Δ/Λ-chirality of four-coordinated, nonplanar Zn(A(^)B)(2) complexes is correlated to the chirality of the bidentate enantiopure (R)-A(^)B or (S)-A(^)B Schiff base building blocks [A(^)B = (R)- or (S)-N-(1-(4-X-phenyl)ethyl)salicylaldiminato-κ(2)N,O with X = OCH(3), Cl, Br]. In the solid-state the (R) ligand chirality induces a Λ-M configuration and the (S) ligand chirality quantitatively gives the Δ-M configuration upon crystallization as deduced from X-ray single crystal studies. The diastereoselections of the pseudotetrahedral zinc-Schiff base complexes in CDCl(3) solution were investigated by (1)H NMR and by vibrational circular dichroism (VCD) spectroscopy. The appearance of two signals for the Schiff-base -CH═N- imine proton in (1)H NMR indicates an equilibrium of both Δ- and Λ-diastereomers with a diastereomeric ratio of roughly 20:80% for all three ligands. VCD proved to be very sensitive to the metal-centered Δ/Λ-chirality because of a characteristic band representing coupled vibrations of the two ligand's C═N stretch modes. The absolute configuration was assigned on the basis of agreement in sign with theoretical VCD spectra from Density Functional Theory calculations.

Catechin derivatives from Parapiptadenia rigida with in vitro wound-healing properties.

Analysis of the ethanolic extract of the bark from Parapiptadenia rigida resulted in the isolation of the new catechin derivatives 4',3''-di-O-methylapocynin-D (10), 4',3''-di-O-methylapocynin-B (11), epigallocatechin-3-O-ferulate (8), and 4'-O-methylepigallocatechin-3-O-ferulate (9) and the catechins 4'-O-methylepigallocatechin-3-O-gallate (6) and 4'-O-methylepicatechin-3-O-gallate (7). These compounds, isolated for the first time from a natural source, are accompanied by the five known catechins 4'-O-methylgallocatechin (1), 4'-O-methylepigallocatechin (2), 3'-O-methylepicatechin (3), epigallocatechin-3-O-gallate (4), and epicatechin-3-O-gallate (5). Compounds 5 and 7 displayed promising wound-healing effects in a scratch assay. Some of the catechin derivatives showed inhibitory effects on NF-κB DNA binding and p38α MAPK activity.

Identifying the missing steps of the autotrophic 3-hydroxypropionate CO2 fixation cycle in Chloroflexus aurantiacus.

The phototrophic bacterium Chloroflexus aurantiacus uses a yet unsolved 3-hydroxypropionate cycle for autotrophic CO(2) fixation. It starts from acetyl-CoA, with acetyl-CoA and propionyl-CoA carboxylases acting as carboxylating enzymes. In a first cycle, (S)-malyl-CoA is formed from acetyl-CoA and 2 molecules of bicarbonate. (S)-Malyl-CoA cleavage releases the CO(2) fixation product glyoxylate and regenerates the starting molecule acetyl-CoA. Here we complete the missing steps devoted to glyoxylate assimilation. In a second cycle, glyoxylate is combined with propionyl-CoA, an intermediate of the first cycle, to form beta-methylmalyl-CoA. This condensation is followed by dehydration to mesaconyl-C1-CoA. An unprecedented CoA transferase catalyzes the intramolecular transfer of the CoA moiety to the C4 carboxyl group of mesaconate. Mesaconyl-C4-CoA then is hydrated by an enoyl-CoA hydratase to (S)-citramalyl-CoA. (S)-Citramalyl-CoA is cleaved into acetyl-CoA and pyruvate by a tri-functional lyase, which previously cleaved (S)-malyl-CoA and formed beta-methylmalyl-CoA. Thus, the enigmatic disproportionation of glyoxylate and propionyl-CoA into acetyl-CoA and pyruvate is solved in an elegant and economic way requiring only 3 additional enzymes. The whole bicyclic pathway results in pyruvate formation from 3 molecules of bicarbonate and involves 19 steps but only 13 enzymes. Elements of the 3-hydroxypropionate cycle may be used for the assimilation of small organic molecules. The 3-hydroxypropionate cycle is compared with the Calvin-Benson-Bassham cycle and other autotrophic pathways.

Carboxylation mechanism and stereochemistry of crotonyl-CoA carboxylase/reductase, a carboxylating enoyl-thioester reductase.

Chemo- and stereoselective reductions are important reactions in chemistry and biology, and reductases from biological sources are increasingly applied in organic synthesis. In contrast, carboxylases are used only sporadically. We recently described crotonyl-CoA carboxylase/reductase, which catalyzes the reduction of (E)-crotonyl-CoA to butyryl-CoA but also the reductive carboxylation of (E)-crotonyl-CoA to ethylmalonyl-CoA. In this study, the complete stereochemical course of both reactions was investigated in detail. The pro-(4R) hydrogen of NADPH is transferred in both reactions to the re face of the C3 position of crotonyl-CoA. In the course of the carboxylation reaction, carbon dioxide is incorporated in anti fashion at the C2 atom of crotonyl-CoA. For the reduction reaction that yields butyryl-CoA, a solvent proton is added in anti fashion instead of the CO(2). Amino acid sequence analysis showed that crotonyl-CoA carboxylase/reductase is a member of the medium-chain dehydrogenase/reductase superfamily and shares the same phylogenetic origin. The stereospecificity of the hydride transfer from NAD(P)H within this superfamily is highly conserved, although the substrates and reduction reactions catalyzed by its individual representatives differ quite considerably. Our findings led to a reassessment of the stereospecificity of enoyl(-thioester) reductases and related enzymes with respect to their amino acid sequence, revealing a general pattern of stereospecificity that allows the prediction of the stereochemistry of the hydride transfer for enoyl reductases of unknown specificity. Further considerations on the reaction mechanism indicated that crotonyl-CoA carboxylase/reductase may have evolved from enoyl-CoA reductases. This may be useful for protein engineering of enoyl reductases and their application in biocatalysis.

Synthesis of C5-dicarboxylic acids from C2-units involving crotonyl-CoA carboxylase/reductase: the ethylmalonyl-CoA pathway.

Fifty years ago, Kornberg and Krebs established the glyoxylate cycle as the pathway for the synthesis of cell constituents from C2-units. However, since then, many bacteria have been described that do not contain isocitrate lyase, the key enzyme of this pathway. Here, a pathway termed the ethylmalonyl-CoA pathway operating in such organisms is described. Isotopically labeled acetate and bicarbonate were transformed to ethylmalonyl-CoA by cell extracts of acetate-grown, isocitrate lyase-negative Rhodobacter sphaeroides as determined by NMR spectroscopy. Crotonyl-CoA carboxylase/reductase, catalyzing crotonyl-CoA + CO2 + NADPH --> ethylmalonyl-CoA- + NADP+ was identified as the key enzyme of the ethylmalonyl-CoA pathway. The reductive carboxylation of an enoyl-thioester is a unique biochemical reaction, unprecedented in biology. The enzyme from R. sphaeroides was heterologously produced in Escherichia coli and characterized. Crotonyl-CoA carboxylase/reductase (or its gene) can be used as a marker for the presence of the ethylmalonyl-CoA pathway, which functions not only in acetyl-CoA assimilation. In Streptomyces sp., it may also supply precursors (ethylmalonyl-CoA) for antibiotic biosynthesis. For methylotrophic bacteria such as Methylobacterium extorquens, extension of the serine cycle with reactions of the ethylmalonyl-CoA pathway leads to a simplified scheme for isocitrate lyase-independent C1 assimilation.

Conformational analysis of the biflavanoid GB2 and a polyhydroxylated flavanone-chromone of Cratoxylum neriifolium.

Three compounds, namely the interesting biflavanonol GB-2(naringenin 1-3, 11-8-dihydroquercetin, 1), 1-4',1-5,11-5,1-7,11-7-pentahydroxyflavanone(l-3,11-8)chromone [naringenin-(3 -8) 5,7-dihydroxychromone, 21 and stigmasterol, have been isolated from the leaves of Cratoxylum neriifolium Kurz. Compounds 1 and 2 show rotameric behavior due to the presence of a single bond between the highly substituted flavanone and flavanonol part and the flavanone and chromone part, respectively. Complete NMR spectral assignments of 1 and 2 have been done at 27 C and 90 C for the first time followed by a study of conformational behavior at room temperature by ROESY.

Sesquiterpene lactones from Montanoa hibiscifolia that inhibit the transcription factor NF-kappa B.

The reinvestigation of the aerial parts of Montanoa hibiscifolia afforded four new eudesmanolides (1-4), three of them with a rare endoperoxide structural element and the fourth with a rare carbonyl function. It also afforded three unusual montabibisciolides (5-7), two (5 and 7) of which are new natural compounds. Additionally, seven germacrolides (8-10 and 12-15) and one melampolide (11) could be isolated, including two new germacrolides (8 and 9). Their structures were elucidated using 1D and 2D NMR measurement as well as ESI, CIMS, and HRMS analyses. Low-energy conformations were obtained by molecular mechanics calculations. The (13)C NMR data of five compounds are reported for the first time. Six sesquiterpene lactones (4, 6, 10, 11, 12, and 14) were investigated for their inhibitory activity on DNA binding of the transcription factor NF-kappa B using Jurkat T cells as well as RAW 264.7 cells. Besides the alpha-methylene-gamma-butyrolactone moiety the epoxy group in the acyl residue might take part in the NF-kappa B inhibitory activity of sesquiterpene lactones.