Akiko Asada

Identification and characterization of α-PVT, α-PBT, and their bromothienyl analogs found in illicit drug products

Recently, thienyl derivatives of cathinones have appeared on the market as new psychoactive substances (NPS). In this study, identification and characterization of 2-(pyrrolidin-1-yl)-1-(thiophen-2-yl)pentan-1-one (α-PVT), 2-(pyrrolidin-1-yl)-1-(thiophen-2-yl)butan-1-one (α-PBT), and their bromothienyl analogs disclosed in illicit products are described. In our analysis, some analogous compounds of α-PVT, which had a bromine substitution on the thiophene ring, were identified in the samples containing α-PVT; 1-(4-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one, 1-(5-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one, and 1-(4,5-dibromothiophen-2-yl)-2-(pyrrolidin-1-yl)pentan-1-one by comparing the analytical data with synthetic reference standards. We also observed 1-(4-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)butan-1-one and 1-(5-bromothiophen-2-yl)-2-(pyrrolidin-1-yl)butan-1-one from a powder product, in which α-PBT was detected. The brominated α-PVTs were also found when overbrominated 1-(thiophen-2-yl)pentan-1-one reacted with pyrrolidine, and they are suspected to be the by-products of α-PVT synthesis. In Japan, cathinone derivatives with a phenyl group as the aromatic ring have been widely controlled by generic scheduling. To escape from such a regulation, analogs with different aromatic groups such as α-PVT and α-PBT appeared on the illicit market of psychoactive compounds. To our knowledge, this is the first report describing identification of α-PBT, and bromothienyl analogs of both α-PVT and α-PBT in illicit drug products. The synthetic method and analytical data shown in this study will be useful for identification of the thienyl derivatives of cathinone analogs.

Characterization of the decomposition of compounds derived from imidazolidinyl urea in cosmetics and patch test materials.

Background. Imidazolidinyl urea releases formaldehyde through decomposition. However, there have been few reports on the chemistry of imidazolidinyl urea in cosmetics.

Isomeric discrimination of synthetic cannabinoids by GC‐EI‐MS: 1‐adamantyl and 2‐adamantyl isomers of N‐adamantyl carboxamides

N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA) and N-(1-adamantyl)-1-pentyl-1H-indole-3-carboxamide (APICA) are carboxamide-type synthetic cannabinoids comprising indazole/indole-3-carboxylic acid and adamantan-1-amine moieties. However, in the case of compounds like APINACA or APICA, adamantyl positional isomers exist, wherein either adamantan-1-amine or adamantan-2-amine is present. These adamantyl positional isomers have not been reported in previous studies, and no analytical data are available. To avoid misidentification of adamantyl carboxamide-type synthetic cannabinoids, it is important to develop methods to discriminate these adamantyl positional isomers. In this study, we report the analytical characterization by gas chromatography-electron ionization-mass spectrometry (GC-EI-MS). For providing analytical standards, we synthesized eight carboxamide-type synthetic cannabinoids (APINACA 2-adamantyl isomer, APICA 2-adamantyl isomer, 5 F-APINACA 2-adamantyl isomer, 5 F-APICA 2-adamantyl isomer, 5Cl-APINACA, 5Cl-APINACA 2-adamantyl isomer, adamantyl-THPINACA, 2-adamantyl-THPINACA) and purchased four 1-adamantyl derivatives (APINACA, APICA, 5 F-APINACA, 5 F-APICA). Although the retention times of the isomers are similar, 1-adamantyl carboxamides can be clearly discriminated from their 2-adamantyl isomers based on their different fragmentation patterns in the EI-MS spectra. Specifically, EI-MS spectra for adamantylindazole carboxamides showed remarkable differences between the 1-adamantyl and 2-adamantyl isomers. On the other hand, EI-MS spectra for adamantylindole carboxamides were similar, but the diagnostic ions of the 2-adamantyl isomers were observed. The method described herein was applicable to all compounds tested in this study and is expected to be of use for isomeric differentiation between other untested adamantyl carboxamide-type synthetic cannabinoids. Copyright

Identification of analogs of LY2183240 and the LY2183240 2′-isomer in herbal products

LY2183240 and the LY2183240 2′-isomer inhibit cellular reuptake and enzymatic hydrolysis of endocannabinoids. These compounds were detected in herbal blend products as designer drugs. Simultaneously, two analogs of LY2183240 and LY2183240 2′-isomer were also detected; (A) 5-[(biphenyl-4-yl)methyl]-1H-tetrazole and (B) 2-(N,N-dimethylamino)-5-[(biphenyl-4-yl)methyl]-1,3,4-oxadiazole. The structure of compound B was identified by nuclear magnetic resonance spectroscopy and X-ray crystallography. To reveal the mechanism of production of these compounds in herbal products, we analyzed the reference standard solution of LY2183240 or the LY2183240 2′-isomer after treatment under various conditions. Compound A was easily formed as a decomposition product of both LY2183240 and the LY2183240 2′-isomer under hydrolysis conditions. Compound B was only detected from the solution of the LY2183240 2′-isomer. These findings suggest that compound B was produced by elimination of N2 from the tetrazole structure; LY2183240 and the LY2183240 2′-isomer may be decomposed at the step of producing herbal blend products, extraction procedure, and/or instrumental analysis. This is the first report to reveal the presence of two analogs of LY2183240 or the LY2183240 2′-isomer in herbal blend products.

Evaluation of carboxamide-type synthetic cannabinoids as CB1/CB2 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.

Enantioseparation of the carboxamide-type synthetic cannabinoids N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(5-fluoropentyl)-1H-indazole-3-carboxamide and methyl [1-(5-fluoropentyl)-1H-indazole-3-carbonyl]-valinate in illicit herbal products

Synthetic cannabinoids, recently used as alternatives to Cannabis sativa, are among the most frequently abused drugs. Identified in 2014, the synthetic cannabinoids N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(5-fluoropentyl)-1H-indazole-3-carboxamide (5F-AB-PINACA) and methyl [1-(5-fluoropentyl)-1H-indazole-3-carbonyl]-valinate (5F-AMB) are carboxamides composed of 1-(5-fluoropentyl)-1H-indazole-3-carboxylic acid and valine amide/methyl ester. Because of their composition, these molecules have pairs of enantiomers derived from the chiral center of their amino acid structures. Previous studies on the identification of 5F-AB-PINACA and 5F-AMB did not consider the existence of enantiomers, and there have been no reports on the enantiopurities of synthetic cannabinoids. We synthesized both enantiomers of these compounds and then separated the enantiomers by liquid chromatography-high-resolution mass spectrometry using a column with a chiral stationary phase consisted with amylose tris (3-chloro-4-methylphenylcarbamate). Under the optimized conditions, the enantiomer resolutions were 2.2 and 2.3 for 5F-AB-PINACA and 5F-AMB, respectively. Analysis of 10 herbal samples containing 5F-AB-PINACA and one herbal sample containing 5F-AMB showed that they all contained the (S)-enantiomer, but the (R)-enantiomer was only detected in two samples and at a ratio of less than 20%.

A simple and selective detection method for aristolochic acid in crude drugs using solid-phase extraction

The official Japanese method for analyzing aristolochic acid I (AA-I) in Asiasarum root using conventional high-performance liquid chromatography (HPLC) is described in the Japanese Pharmacopoeia, Sixteenth Edition. Interfering peaks of AA-I sometimes appear after HPLC analysis of crude drugs. A selective analytical method is needed to determine definitively whether AA-I is present in crude drugs. In this study, we developed a selective method that combined solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) which may be useful for identifying AA-I in crude drugs and for quality control.

Characterization of a new illicit phosphodiesterase-type-5 inhibitor identified in the softgel shell of a dietary supplement

Graphical abstract Figure. No Caption available. HighlightsA novel sildenafil analog found from a dietary supplement was investigated by UV spectroscopy and high‐resolution MS analysis.We synthesized propoxyphenyl noracetildenafil as the reference standard.The illicit sildenafil analogs were mainly detected from the shell of the capsule sample. ABSTRACT A new sildenafil analog has been identified in the softgel shell of a dietary supplement. The compound was investigated by UV spectroscopy and high‐resolution MS analysis, leading to the proposed structure 1‐methyl‐5‐{5‐[2‐(4‐methylpiperazin‐1‐yl)acetyl]‐2‐propoxyphenyl}‐3‐propyl‐1,6‐dihydro‐7H‐pyrazolo[4,3‐d]pyrimidin‐7‐one. A synthetic reference compound with the proposed structure was prepared, and the two sets of analytical data were compared, confirming the structure of the new compound. The compound was named propoxyphenyl noracetildenafil from its structure and similarity with the known compound.

Detection of pyrovalerone as a possible synthetic by-product of 4′-methyl-α-pyrrolidinohexanophenone and 4-methyl-α-ethylaminopentiophenone in illicit drug products

PurposeImpurity profiling is an important intelligence-gathering tool that can be used to link batches of drugs, and it provides valuable insights into manufacturing and supply trends in new psychoactive substances. In a routine analysis, we detected trace amounts of pyrovalerone in illicit drug products. In this study, we investigated the cause of pyrovalerone’s presence in the illicit drug products containing 4′-methyl-α-pyrrolidinohexanophenone (MPHP) or 4-methyl-α-ethylaminopentiophenone (4-methyl-α-EAPP).MethodsWe analyzed the compounds in illicit drug products and raw material using liquid chromatography–photodiode array detection, gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry.ResultsWe detected trace amounts of pyrovalerone in four illicit drug products containing MPHP or 4-methyl-α-EAPP. In every case, the amount of pyrovalerone in the illicit drug products was much lower than that of MPHP or 4-methyl-α-EAPP. We assumed that pyrovalerone was produced unintentionally. Structurally, pyrovalerone differs from MPHP with respect to the length of the alkyl side chain, and for 4-methyl-α-EAPP, the amine at the α-position is different (it bears an ethylamine instead of pyrrolidine). Pyrovalerone is thought to be produced in two different ways, as a synthetic by-product of both MPHP and 4-methyl-α-EAPP.ConclusionsWe assumed that pyrovalerone was derived from an impurity in a raw material or arose from contamination during the amination process. Impurity analysis, such as that described in this study, will aid in impurity profiling of cathinones.

Quantification of 1,3-dimethylol-5,5-dimethylhydantoin and its decomposition products in cosmetics by high-performance liquid chromatography

We developed a method to simultaneously and quantitatively measure four compounds commonly found in commercial cosmetics: 1,3-dimethylol-5,5-dimethylhydantoin (DMDMH) and its decomposition products 1-hydroxymethyl-5,5-dimethylhydantoin (1-MDMH), 3-hydroxymethyl-5,5-dimethylhydantoin (3-MDMH), and 5,5-dimethylhydantoin (DMH). In addition, we succeeded in synthesizing 3-MDMH selectively from DMDMH. Our new analytical method involves the use of an HPLC system and an octadecylsilanized silica column. HPLC calibration curves for DMDMH, 1-MDMH, 3-MDMH, and DMH were linear over the wide concentration ranges. In cosmetics whose pH is basic, the recovery of 3-MDMH and DMH was substantially higher than 100%, whereas that of DMDMH and 1-MDMH was considerably lower than 100%, however, the average recovery of the four compounds was in the range of 85-105%. It was suggested that the latter tend to decompose to the former. We confirmed that our HPLC separation method is suitable for the analysis of dimethyhydantoins without the progress of decomposition and should be useful for rapid analysis of these compounds in cosmetics.