Two new-type cannabimimetic quinolinyl carboxylates, QUPIC and QUCHIC, two new cannabimimetic carboxamide derivatives, ADB-FUBINACA and ADBICA, and five synthetic cannabinoids detected with a thiophene derivative α-PVT and an opioid receptor agonist AH-7921 identified in illegal products

We identified two new-type cannabimimetic quinolinyl carboxylates, quinolin-8-yl 1-pentyl-(1H-indole)-3-carboxylate (QUPIC, 1) and quinolin-8-yl 1-(cyclohexylmethyl)-1H-indole-3-carboxylate (QUCHIC, 2); and two new cannabimimetic carboxamide derivatives, N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (ADB-FUBINACA, 3) and N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-pentyl-1H-indole-3-carboxamide (ADBICA, 4), as designer drugs in illegal products. Compound 3 was reported to have a potent affinity for cannabinoid CB₁ receptor by Pfizer in 2009, but this is the first report of its detection in illegal products. No chemical or pharmacological data for compounds 1, 2, and 4 have appeared until now, making this the first report on these compounds. We also detected synthetic cannabinoids, APICA N-(5-fluoropentyl) analog (5), APINACA N-(5-fluoropentyl) analog (6), UR-144 N-(5-chloropentyl) analog (7), JWH-122 N-(5-chloropentyl) analog (8), and AM-2201 4-methoxynaphthyl analog (4-MeO-AM-2201, 9) herein as newly distributed designer drugs in Japan. It is of interest that compounds 1 and 2 were detected with their synthetic component, 8-quinolinol (10). A stimulant thiophene analog, α-pyrrolidinovalerothiophenone (α-PVT, 11), and an opioid receptor agonist, 3,4-dichloro-N-([1-(dimethylamino)cyclohexyl]methyl)benzamide (AH-7921, 12), were also detected as new types of designer drugs coexisting with several synthetic cannabinoids and cathinone derivatives in illegal products.     

Identification of new synthetic cannabinoid analogue APINAC (adamantan-1-yl 1-pentyl-1H-indazole-3-carboxylate) with other synthetic cannabinoid MDMB(N)-Bz-F in illegal products

Two synthetic cannabinoid analogues were detected using high-performance liquid chromatography (HPLC)–diode array detector, and gas chromatography–time-of-flight-mass spectrometry during the inspection of illegal products in an airmail package. The analogues were separated by semi-preparative HPLC, and their structures were determined by performing liquid chromatography–high-resolution-mass spectrometry, infrared analysis, and nuclear magnetic resonance spectroscopy. Compound 1 was MDMB(N)-Bz-F, which has been reported previously. Compound 2 was elucidated as adamantan-1-yl 1-pentyl-1H-indazole-3-carboxylate (APINAC), in which the amide group of APINACA was replaced with an ester group. Because there has been no chemical or pharmacological data about this compound until now, this is the first report of its detection in illegal products.     

Sensitive identification and quantitation of parent forms of six synthetic cannabinoids in urine samples of human cadavers by liquid chromatography–tandem mass spectrometry

Human urine samples are easier to obtain than human blood samples due to noninvasiveness. The urine levels of synthetic cannabinoids (SCs) in unchanged forms, however, are usually much lower than their blood and tissue levels and cannot be detected in most cases. Therefore, in the present work a sensitive analytical method was devised for the determination of urine levels of six SCs in unchanged forms such as N-(1-amino-3-methy-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA), N-(1-amino-3-methy-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA), N-[(1S)-1-(1-aminocarbonyl)-2-methyl-propyl]-1-(cyclohexylmethyl)-1H-indazole-3-carboxamide (AB-CHMINACA), N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(cyclohexylmethyl)-1H-indazole-3-carboxamide (MAB-CHMINACA), methyl-2-[1-(5-fluoropentyl)-1H-indazole-3-carboxamido]-3-methylbutanoate (5F-AMB) and methyl-2-[1-(5-fluoropentyl)-1H-indazole-3-carboxamido]-3,3-dimethylbutanoate (5F-ADB). These SCs were extracted from urine via liquid–liquid extraction. The identification and quantitation were performed by a relatively new type of an instrument for liquid chromatography–tandem mass spectrometry. The limits of detection were as low as 3–8 pg/mL, and the quantitation range was 10–1000 pg/mL using 400 μL of urine. The urine levels of AB-PINACA and AB-FUBINACA of victim 1 were 23 and 10 pg/mL, those of AB-CHMINACA and 5F-AMB of victim 2 were 239 and 19 pg/mL, and those of MAB-CHMINACA and 5F-ADB of victim 3 were 229 and 19 pg/mL, respectively. To our knowledge, this is the first report dealing with successful analysis of low levels of parent synthetic cannabinoids in authentic human urine specimens.     

Two new synthetic cannabinoids, AM-2201 benzimidazole analog (FUBIMINA) and (4-methylpiperazin-1-yl)(1-pentyl-1H-indol-3-yl)methanone (MEPIRAPIM), and three phenethylamine derivatives, 25H-NBOMe 3,4,5-trimethoxybenzyl analog, 25B-NBOMe, and 2C-N-NBOMe, identified in illegal products

Two new types of synthetic cannabinoids, an AM-2201 benzimidazole analog (FUBIMINA, 1) and (4-methylpiperazin-1-yl)(1-pentyl-1H-indol-3-yl)methanone (MEPIRAPIM, 2), and three newly emerged phenethylamine derivatives, 25B-NBOMe (3), 2C-N-NBOMe (4), and a 25H-NBOMe 3,4,5-trimethoxybenzyl analog (5), were detected in illegal products distributed in Japan. The identification was based on liquid chromatography–mass spectrometry (LC–MS) and gas chromatography–mass spectrometry (GC–MS), high-resolution MS, and nuclear magnetic resonance analyses. Different from the representative synthetic cannabinoids, such as JWH-018, which have a naphthoylindole moiety, compounds 1 and 2 were completely new types of synthetic cannabinoids; compound 1 had a benzimidazole group in place of an indole group, and compound 2 had a 4-methylpiperazine group in place of the naphthyl group. Compounds 3 and 4 were N-o-methoxybenzyl derivatives of 2,5-dimethoxyphenethylamines (25-NBOMe series), which had been previously detected in European countries, but have newly emerged in Japan. Compound 5 had an N-trimethoxybenzyl group in place of an N-o-methoxybenzyl group. Data on the chemistry and pharmacology of compounds 1, 2, and 5 have never been reported to our knowledge.     

Evaluation of carboxamide-type synthetic cannabinoids as CB<Subscript>1</Subscript>/CB<Subscript>2</Subscript> receptor agonists: difference between the enantiomers

Recently, carboxamide-type synthetic cannabinoids have been distributed globally as new psychoactive substances (NPS). Some of these compounds possess asymmetric carbon, which is derived from an amide moiety composed of amino acid derivatives (i.e., amides or esters of amino acids). In this study, we synthesized both enantiomers of synthetic cannabinoids, N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(2-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA 2-fluorobenzyl isomer), N-(1-amino-1-oxo-3-phenylpropan-2-yl)-1-(cyclohexylmethyl)-1H-indazole-3-carboxamide (APP-CHMINACA), ethyl [1-(5-fluoropentyl)-1H-indazole-3-carbonyl]valinate (5F-EMB-PINACA), ethyl [1-(4-fluorobenzyl)-1H-indazole-3-carbonyl]valinate (EMB-FUBINACA), and methyl 2-[1-(4-fluorobenzyl)-1H-indole-3-carboxamido]-3,3-dimethylbutanoate (MDMB-FUBICA), which were reported as NPS found in Europe from 2014 to 2015, to evaluate their activities as CB₁/CB₂ receptor agonists. With the exception of (R) MDMB-FUBICA, all of the tested enantiomers were assumed to be agonists of both CB₁ and CB₂ receptors, and the EC₅₀ values of the (S)-enantiomers for the CB₁ receptors were about five times lower than those of (R)-enantiomers. (R) MDMB-FUBICA was shown to function as an agonist of the CB₂ receptor, but lacks CB₁ receptor activity. To the best of our knowledge, this is the first report to show that the (R)-enantiomers of the carboxamide-type synthetic cannabinoids have the potency to activate CB₁ and CB₂ receptors. The findings presented here shed light on the pharmacological properties of these carboxamide-type synthetic cannabinoids in forensic cases.     

Identification of two new-type synthetic cannabinoids, N-(1-adamantyl)-1-pentyl-1H-indole-3-carboxamide (APICA) and N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA), and detection of five synthetic cannabinoids, AM-1220, AM-2233, AM-1241, CB-13 (CRA-13), and AM-1248, as designer drugs in illegal products

Two new-type synthetic cannabinoids, N-(1-adamantyl)-1-pentyl-1H-indole-3-carboxamide (APICA, 1) and N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA, 2), have been identified as designer drugs in illegal products being sold in Japan. The identification was based on liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), high-resolution MS and nuclear magnetic resonance (NMR) analyses. Both mass and NMR spectrometric data revealed that 1 was 1-pentyl-N-tricyclo[3.3.1.1^3,7]dec-1-yl-1H-indole-3-carboxamide, and 2 was 1-pentyl-N-tricyclo[3.3.3.1.^3,7]dec-1-yl)-1H-indazole-3-carboxamide. Although many of the synthetic cannabinoids detected in illegal products, such as JWH-018, have a 3-carbonyl indole moiety, compounds 1 and 2 are a new type of synthetic cannabinoid having an amide and an adamantyl group, and 2 also has an indazole group in place of an indole group. There has been no synthetic, chemical, or biological information about 1 or 2 until now, making this the first report of these cannabimimetic compounds (1 and 2) as designer drugs. In addition, five synthetic cannabinoids, AM-1220, AM-2233, AM-1241, CB-13 (CRA-13), and AM-1248, are also described herein as newly distributed designer drugs in Japan.     

Identification of the synthetic cannabinoid <Emphasis Type="Italic">N</Emphasis>-(2-phenyl-propan-2-yl)-1-(4-cyanobutyl)-1<Emphasis Type="Italic">H</Emphasis>-indazole-3-carboxamide (CUMYL-4CN-BINACA) in a herbal mixture product

We were the first to detect N-(2-phenylpropan-2-yl)-1-(4-cyanobutyl)-1H-indazole-3-carboxamide (common name CUMYL-4CN-BINACA) as a new synthetic cannabinoid, on the illegal market in Bursa, Turkey. To elucidate the chemical structure, the dried herbal mixture was extracted with methanol. The extract was purified by column chromatography. Pure compound was analyzed by gas chromatography–mass spectrometry (GC–MS), attenuated total reflection Fourier-transform infrared spectroscopy (FT-IR), and one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. The GC–MS, FT-IR and ¹H and ¹³C NMR spectra of the compound coincided well with the reference data. All protons and carbons were assigned by their couplings and correlations observed in ¹H-¹H correlation spectroscopy, ¹H-¹³C heteronuclear multiple bond correlation, and ¹H-¹³C heteronuclear single quantum coherence spectra. On the basis of the spectral data, the compound was identified as CUMYL-4CN-BINACA. Herewith, we report analytical characteristics of CUMYL-4CN-BINACA enabling its (and possible analogues thereof) determination in criminal seizures.     

Identification of a new synthetic cannabinoid in a herbal mixture: 1-butyl-3-(2-methoxybenzoyl)indole

Two unknown cannabimimetic compounds were detected in a seized herbal mixture after gas chromatography–mass spectrometry (GC–MS) screening. To elucidate the chemical structures, 0.3 g of the dried plant material was extracted with methanol and concentrated under reduced pressure. The extract was purified by silica gel column chromatography with methylene chloride and methanol. Pure compounds were isolated by preparative high-performance liquid chromatography (HPLC) and then analyzed by electrospray ionization (ESI) mass spectrometry (MS) with direct flow injection, high-resolution ESI-time-of-flight (TOF)–MS and one-dimensional and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. GC–MS spectra showed that the base ion at m/z 321 for compound 1 was the same as that of 1-pentyl-3-(4-methoxybenzoyl)indole (RCS-4), and the fragment ions were almost the same as those of RCS-4. The GC–MS spectrum of compound 2 was very similar to that of compound 1 except that the mass numbers of the fragment ions at m/z 290, 200, 186, and 173 of compound 2 were equally smaller than those of compound 1 by 14 amu. From these GC–MS results, compound 1 was assumed to be the 2- or 3-methoxy isomer of RCS-4, and compound 2 was assumed to be a 1-butylindole homologue of compound 1. The ESI mass spectra showed a single peak at m/z 322.33 for compound 1 and a single peak at m/z 308.25 for compound 2, which showed the masses of the protonated ions. High-resolution TOF–MS spectra showed the accurate mass numbers of protonated molecular ions at m/z 322.180512 for compound 1 and at m/z 308.164895 for compound 2, suggesting the molecular formulas of C₂₁H₂₃NO₂ and C₂₀H₂₁NO₂, respectively. The ¹H NMR spectra showed signals that suggested 23 and 21 protons for compounds 1 and 2, respectively, while the respective ¹³C NMR spectra showed 21 and 20 carbon signals. All protons and carbons were assigned by their couplings and correlations observed in ¹H–¹H correlation spectroscopy (COSY), ¹H–¹³C heteronuclear multiple bond correlation (HMBC), and ¹H–¹³C heteronuclear single quantum coherence (HSQC) spectra. On the basis of the spectral data, compound 1 was identified as the 2-methoxy isomer of RCS-4; compound 2 was identified for the first time as 1-butyl-3-(2-methoxybenzoyl)indole. Phenazepam and 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) were also identified as coexisting drugs in the herbal mixture. The contents of compounds 1 and 2 in the mixture were calculated to be 22.4 and 3.45 mg/g, respectively.     

Analysis of azepane isomers of AM-2233 and AM-1220, and detection of an inhibitor of fatty acid amide hydrolase [3′-(aminocarbonyl)(1,1′-biphenyl)-3-yl]-cyclohexylcarbamate (URB597) obtained as designer drugs in the Tokyo area

During our careful survey of unregulated drugs from November 2011 to January 2012 in the Tokyo area, we found two new compounds in commercial products. The first was identified as the benzoylindole (2-iodophenyl)[1-(1-methylazepan-3-yl)-1H-indol-3-yl]methanone (2), which is the azepane isomer of AM-2233 (1). Compound 2 was isolated by silica gel column chromatography, and was identified through a combination of liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, accurate mass spectrometry, and nuclear magnetic resonance spectroscopy. The second compound was identified as [3′-(aminocarbonyl)(1,1′-biphenyl)-3-yl]-cyclohexylcarbamate (URB597, 5) by comparing analytical data with that of the authentic compound. For quantitation of these three compounds, each commercial product was extracted with methanol under ultrasonication to prepare the solution for analysis by liquid chromatography with ultraviolet detection. The occurrence of compounds 1 and 2, and AM-1220 (3) and its azepane isomer (4) in 29 commercial products found in the Tokyo area are also shown in this report.     

Identification and quantitation of a benzoylindole (2-methoxyphenyl)(1-pentyl-1H-indol-3-yl)methanone and a naphthoylindole 1-(5-fluoropentyl-1H-indol-3-yl)-(naphthalene-1-yl)methanone (AM-2201) found in illegal products obtained via the Internet and their cannabimimetic effects evaluated by in vitro [35S]GTP��S binding assays

During our careful surveillance of unregulated drugs in January to February 2011, we found two new compounds used as adulterants in herbal products obtained via the Internet. These compounds were identified by liquid chromatography?Cmass spectrometry, gas chromatography-mass spectrometry, accurate mass spectrometry, and nuclear magnetic resonance spectroscopy. The first compound identified was a benzoylindole (2-methoxyphenyl)(1-pentyl-1H-indol-3-yl)methanone (1), which is a positional isomer of (4-methoxyphenyl)(1-pentyl-1H-indol-3-yl)methanone (RCS-4, 4). The second compound was 1-(5-fluoropentyl-1H-indol-3-yl)-(naphthalene-1-yl)methanone (AM-2201, 2). The compound 2 has been reported to be a cannabinoid receptor agonist. Because the cannabimimetic effects of compounds 1 and 4 have not been reported to date, their biological activities were evaluated by measuring the activation of [³⁵S] guanosine-5??-O-(3-thio)-triphosphate binding to guanine nucleotide-binding proteins, together with those of other synthetic cannabimimetic compounds. For quantitation of the above two compounds (1 and 2) and previously identified compounds (AM-694, 3; JWH-122, 5; RCS-4, 4), each product was extracted with methanol under ultrasonication to prepare a sample solution for analysis by liquid chromatography with ultraviolet detection. Each of four commercial products contained some of cannabimimetic indoles 1?C5; their contents ranged from 14.8 to 185 mg per pack.     

Differentiation of AB-FUBINACA and its five positional isomers using liquid chromatography–electrospray ionization-linear ion trap mass spectrometry and triple quadrupole mass spectrometry

Purpose

Positional isomer differentiation is crucial for forensic analysis. The aim of this study was to differentiate AB-FUBINACA positional isomers using liquid chromatography (LC)–electrospray ionization (ESI)-linear ion trap mass spectrometry (LIT-MS) and LC–ESI-triple quadrupole mass spectrometry (QqQ-MS).

Methods

AB-FUBINACA, its two fluorine positional isomers on the phenyl ring, and three methyl positional isomers in the carboxamide side chain were analyzed by LC–ESI-LIT-MS and LC–ESI-QqQ-MS.

Results

Four of the positional isomers, excluding AB-FUBINACA and its 3-fluorobenzyl isomer, were chromatographically separated on an ODS column in isocratic mode. ESI-LIT-MS could discriminate only three isomers, i.e., the 2-fluorobenzyl isomer, the N-(1-amino-2-methyl-1-oxobutan-2-yl) isomer, and the N-(1-amino-1-oxobutan-2-yl)-N-methyl isomer, based on their characteristic product ions observed at the MS³ stage in negative mode. ESI-QqQ-MS differentiated all six isomers in terms of the relative abundances of the product ions that contained the isomeric moieties involved in collision-induced dissociation reactions. The six isomers were more clearly and significantly differentiated upon comparison of the logarithmic values of the product ion abundance ratios as a function of collision energy.

Conclusions

The present LC–MS methodologies were useful for the differentiation of a series of AB-FUBINACA positional isomers.

     

Chemical analysis of a benzofuran derivative, 2-(2-ethylaminopropyl)benzofuran (2-EAPB), eight synthetic cannabinoids,five cathinone derivatives,and five other designer drugs newly detected in illegal products

From November 2013 to May 2014, 19 newly distributed designer drugs were identified in 104 products in our ongoing survey of illegal products in Japan. The identified compounds included 8 synthetic cannabinoids, FUB-PB-22 (1), 5-fluoro-NNEI indazole analog (5-fluoro-MN-18, 2), AM-2201 indazole analog (THJ-2201, 3), XLR-12 (4), 5-fluoro-AB-PINACA (5), 5-chloro-AB-PINACA (6), AB-CHMINACA (7), and 5-fluoro-AMB (8); 5 cathinone derivatives, DL-4662 (9), α-PHP (10), 4-methoxy-α-POP (11), 4-methoxy-α-PHPP (12), and 4-fluoro-α-PHPP (13); and 6 other substances, namely, the benzofuran derivative 2-(2-ethylaminopropyl)benzofuran (2-EAPB, 14), nitracaine (15), diclofensine (16), diphenidine (17), 1-benzylpiperidine (18), and acetylfentanyl (19). To our knowledge, this is the first report on the chemical properties of compounds 9–11 and 14. A total of 33 designer drugs, including compounds 1–19, were detected in the 104 illegal products, in 60 different combination patterns. The numbers of detected compounds per product ranged from 1 to 7. In addition, several products contained three different types of compounds, such as synthetic cannabinoids, cathinone derivatives, and phenethylamine derivatives per product. It is apparent that the types of compounds emerging as illegal products are becoming more diverse, as are their combinations.     

Chemical constituents and DNA sequence analysis of a psychotropic herbal product

In recent years, the distribution of a variety of psychotropic products, especially “spice” and “herbal blends,” which are advertised to have narcotic-like effects, has become more widespread in the Japanese illegal drug market. We recently found two synthetic annabinoids, cannabicyclohexanol and JWH-018, that serve as adulterants in herbal products purchased via the Internet. In this study, we focused on a herbal product being sold as incense, which showed unknown components by liquid chromatography-mass spectrometry (LC-MS). The product did not show any peak corresponding to the above synthetic cannabinoids, but seven other peaks were identified by high-performance liquid chromatography and LC-MS. We identified them as N-methyltyramine (1), (R)-normacromerine (2), (R)-macromerine (3), (S)-vasicine (4), mescaline (5), harmaline (6), and harmine (7) by polarimetry, LC-MS, gas chromatography-mass spectrometry, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. We also used DNA sequence analyses to identify the plant species of the product. As a result of the sequencing of trnL-F, internal transcribed spacer (ITS), and rpl16 intron regions, three sequences derived from Coryphantha macromeris (Cactaceae), Peganum harmala (Zygophyllaceae), and Turnera diffusa (Turneraceae) were observed. Compounds 2 and 3, both phenethylamines, were reported to cause hallucinogenic effects and are frequently found in Coryphantha genus (Cactaceae). Therefore, the plant source of these compounds was considered to be C. macromeris. Compound 5 is known to be a psychoactive phenethylamine found in peyote (Lophophora williamsii) and San Pedro cactus (Trichocereus pachanoi). The β-carboline alkaloids 6 and 7 are known to be found in the seeds of P. harmala. Therefore, there seems to be no contradiction between the chemical constituents and the plant species estimated by DNA analyses, except for compound 5. This is the first report dealing with identification of the psychoactive cactus C. macromeris and its constituent compounds in a herbal product distributed in the illegal drug market.     

Comprehensive analytical and structural characteristics of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA)

Purpose

The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB.

Methods

The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used.

Results

We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA.

Conclusions

To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.

     

Identification of two new-type designer drugs, piperazine derivative MT-45 (I-C6) and synthetic peptide Noopept (GVS-111), with synthetic cannabinoid A-834735, cathinone derivative 4-methoxy-α-PVP, and phenethylamine derivative 4-methylbuphedrine from illegal products

We identified two new-type designer drugs, piperazine derivative MT-45 [1-cyclohexyl-4-(1,2-diphenylethyl)piperazine, synonym: I-C6, 1] and synthetic peptide Noopept [ethyl 2-(1-(2-phenylacetyl)pyrrolidine-2-carboxamido)acetate, synonym: GVS-111, 2], in chemical and herbal products. MT-45 (1) was previously reported as an opiate-like analgesic substance, and Noopept (2) was reported to have nootropic (cognitive enhancer) activity. We also detected two synthetic cannabinoids, A-834735 (3) and QUPIC N-(5-fluoropentyl) analog (synonym: 5-fluoro-PB-22, 4), in the illegal products. A-834735 (3) was previously reported to act as an agonist at both cannabinoid CB₁ and CB₂ receptors. In addition, cathinone derivative 4-methoxy-α-pyrrolidinovalerophenone (4-methoxy-α-PVP, 5) and phenethylamine derivative 4-methylbuphedrine (6) were newly detected with known cathinone derivative 4-methylbuphedrone (7) in the products.     

Stereoselective synthesis, in vitro, and initial in vivo evaluation of 1-methylpiperidin-4-yl α-hydroxy-α-(1-iodo-1-propen-3-yl)-α-phenylacetate (IPIP): a novel radioiodinated molecular probe with high affinity for the muscarinic receptor

1-Methylpiperidin-4-yl α-hydroxy-α-(1-iodo-1-propen-3-yl)-α-phenylacetate (IPIP, Fig. 1) was investigated as a potential radioiodinated molecular probe targeted to the muscarinic receptor complex. The IPIP stereoisomers were synthesized via a chiral intermediate in >95% enantiomeric excess. The R-isomers demonstrated a M₁ to M₂ subtype selectivity of approximately 3 to 1 and the S-isomers demonstrated non-subtype selective binding in vitro. IPIP was radiolabeled with iodide-125 with an average radiochemical yield of 74.4% (±14.8, N = 5), specific activities >800 mCi/μmol, and radiochemical purities >97%. In vivo the Z-isomers demonstrated high uniform cerebral uptake suggesting non-subtype selective binding. In contrast, E-R-IPIP, after allowing a low uptake in M₂ rich areas to clear, demonstrated a retention of activity in M₁ and M₄ rich cerebral regions. In addition, the cerebral uptake of E-R-IPIP and Z-S-IPIP were inhibited by 70–90% via pretreatment with R-QNB, an established muscarinic antagonist. An ex vivo metabolism study demonstrated Z-S-IPIP was stable at the receptor site with an absence of radiolabeled metabolites.

Full-size image (6K)

Fig. 1. QNB and various radiolabeled mAChR antagonists.

Preclinical evaluation of BAY 1075553, a novel 18F-labelled inhibitor of prostate-specific membrane antigen for PET imaging of prostate cancer

Purpose

Prostate-specific membrane antigen (PSMA) is a transmembrane protein overexpressed in prostate cancer and is therefore being explored as a biomarker for diagnosing and staging of the disease. Here we report preclinical data on BAY 1075553 (a 9:1 mixture of (2S,4S)- and (2R,4S)-2-[¹⁸F]fluoro-4-phosphonomethyl-pentanedioic acid), a novel ¹⁸F-labelled small molecule inhibitor of PSMA enzymatic activity, which can be efficiently synthesized from a direct radiolabelling precursor.

Methods

The ¹⁸F-radiolabelled stereoisomers of 2-[¹⁸F]fluoro-4-(phosphonomethyl)-pentanedioic acid were synthesized from their respective isomerically pure precursors dimethyl 2-{[bis(benzyloxy)phosphoryl]methyl}-4-(tosyloxy)pentanedioate. In vivo positron emission tomography (PET) imaging and biodistribution studies were conducted in mice bearing LNCaP, 22Rv1 and PC-3 tumours. Pharmacokinetic parameters and dosimetry estimates were calculated based on biodistribution studies in rodents. For non-clinical safety assessment (safety pharmacology, toxicology) to support a single-dose human microdose study, off-target effects in vitro, effects on vital organ functions (cardiovascular in dogs, nervous system in rats), mutagenicity screens and an extended single-dose study in rats were conducted with the non-radioactive racemic analogue of BAY 1075553.

Results

BAY 1075553 showed high tumour accumulation specific to PSMA-positive tumour-bearing mice and was superior to other stereoisomers tested. Fast clearance of BAY 1075553 resulted overall in low background signals in other organs except for high uptake into kidney and bladder which was mainly caused by renal elimination of BAY 1075553. A modest uptake into bone was observed which decreased over time indicating organ-specific uptake as opposed to defluorination of BAY 1075553 in vivo. Biodistribution studies found highest organ doses for kidneys and the urinary bladder wall resulting in a projected effective dose (ED) in humans of 0.0219 mSv/MBq. Non-clinical safety studies did not show off-target activity, effects on vital organs function or dose-dependent adverse effects.

Conclusion

BAY 1075553 was identified as a promising PET tracer for PSMA-positive prostate tumours in preclinical studies. BAY 1075553 can be produced using a robust, direct radiosynthesis procedure. Pharmacokinetic, toxicology and safety pharmacology studies support the application of BAY 1075553 in a first-in-man microdose study with single i.v. administration.     

Syntheses and biological evaluation of (18)F-labeled 3-(1-benzyl-piperidin-4-yl)-1-(1-methyl-1H-indol-3-yl)propan-1-ones for in vivo mapping of acetylcholinesterase

We synthesized novel (18)F-labeled acetylcholinesterase (AChE) inhibitors, 3-[1-(3- and 4-[(18)F]fluoromethylbenzyl)piperidin-4-yl]-1-(1-methyl-1H-i ndol-3-yl )propan-1-ones ([(18)F]1 and [(18)F]2) and 3-[1-(4-[(18)F]fluorobenzyl)piperidin-4-yl]-1-(1-methyl-1H-i ndol-3-yl )propan-1-one ([(18)F]3) in high yields (decay-corrected, 25%-40%) and with high effective specific activities (>37 GBq/micromol). Tissue distribution studies of the [(18)F]1 and the [(18)F]3 in mice showed the nonspecific bindings in brain regions, with metabolic defluorination of the [(18)F]1. The result suggests that these radioligands may not be suitable agents for in vivo mapping of AChE, despite their potent in vitro anti-AChE activities.     

Facile synthesis of carbon-11-labeled arylpiperazinylthioalkyl derivatives as new PET radioligands for imaging of 5-HT1AR

Carbon-11-labeled arylpiperazinylthioalkyl derivatives, 2-((4-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)butyl)thio)benzo[d]oxazole ([¹¹C]5a), 2-((4-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)butyl)thio)-5,7-dimethylbenzo[d]oxazole ([¹¹C]5c), 2-((4-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)butyl)thio)benzo[d]thiazole ([¹¹C]5e), 2-((6-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)hexyl)thio)benzo[d]oxazole ([¹¹C]5g), 2-((6-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)hexyl)thio)-5,7-dimethylbenzo[d]oxazole ([¹¹C]5i), and 2-((6-(4-(2-[¹¹C]methoxyphenyl)piperazin-1-yl)hexyl)thio)benzo[d]thiazole ([¹¹C]5k), were prepared from their corresponding phenol precursors with [¹¹C]CH₃OTf through O-[¹¹C]methylation and isolated by a simplified solid-phase extraction (SPE) method using a Sep-Pak Plus C18 cartridge in 50-60% (n=5) radiochemical yields based on [¹¹C]CO₂ and decay corrected to end of bombardment (EOB). The overall synthesis time from EOB was 23 min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 277.5±92.5 GBq/μmol (n=5).