Test purchase,synthesis, and characterization of 2‐methoxydiphenidine (MXP) and differentiation from its meta‐ and para‐substituted isomers

The structurally diverse nature of the 1,2‐diphenylethylamine template provides access to a range of substances for drug discovery work but some have attracted attention as ‘research chemicals’. The most recent examples include diphenidine, i.e. 1‐(1,2‐diphenylethyl)piperidine and 2‐methoxydiphenidine, i.e. 1‐[1‐(2‐methoxyphenyl)‐2‐phenylethyl]piperidine (MXP, methoxyphenidine, 2‐MXP) that have been associated with uncompetitive N‐methyl‐D‐aspartate (NMDA) receptor antagonist activity. Analytical challenges encountered during chemical analysis include the presence of positional isomers. Three powdered samples suspected to contain 2‐MXP were obtained from three Internet retailers in the United Kingdom and subjected to analytical characterization by gas chromatography (GC) and high performance liquid chromatography (HPLC) coupled to various forms of mass spectrometry (MS). Nuclear magnetic resonance spectroscopy, infrared spectroscopy and thin layer chromatography were also employed. This was supported by the synthesis of all three isomers (2‐, 3‐ and 4‐MXP) by two different synthetic routes. The analytical data obtained for the three purchased samples were consistent with the synthesized 2‐MXP standard and the differentiation between the isomers was possible. Distinct stability differences were observed for all three isomers during in‐source collision‐induced dissociation of the protonated molecule when employing detection under HPLC selected‐ion monitoring detection, which added to the ability to differentiate between them. Furthermore, the analysis of a 2‐MXP tablet by matrix assisted inlet ionization Orbitrap mass spectrometry confirmed that it was possible to detect the protonated molecule of 2‐MXP directly from the tablet surface following addition of 3‐nitrobenzonitrile as the matrix. Copyright © 2015 John Wiley & Sons, Ltd.     

Syntheses and analytical characterizations of novel (2‐aminopropyl)benzo[b]thiophene (APBT) based stimulants

Two groups of amphetamine‐like drugs with psychostimulant properties that were first developed during the course of scientific studies and later emerged as new psychoactive substances (NPS) are based on the (2‐aminopropyl)indole (API) and (2‐aminopropyl)benzofuran (APB) structural scaffolds. However, sulfur‐based analogs with a benzo[b]thiophene structure (resulting in (2‐aminopropyl)benzo[b]thiophene (APBT) derivatives) have received little attention. In the present investigation, all six racemic APBT positional isomers were synthesized in an effort to understand their structure–activity relationships relative to API‐ and APB‐based drugs. One lesson learned from the NPS phenomenon is that one cannot exclude the appearance of such substances on the market. Therefore, an in‐depth analytical characterization was performed, including various single‐ and tandem mass spectrometry (MS) and ionization platforms coupled to gas chromatography (GC) and liquid chromatography (LC), nuclear magnetic resonance spectroscopy (NMR), and solid phase and GC condensed phase infrared spectroscopy (GC‐sIR). Various derivatizations have also been explored; it was found that all six APBT isomers could be differentiated during GC analysis after derivatization with heptafluorobutyric anhydride and ethyl chloroformate (or heptafluorobutyric anhydride and acetic anhydride) under non‐routine conditions. Discriminating analytical features can also be derived from NMR, GC‐EI/CI‐ single‐ and tandem mass spectrometry, LC (pentafluorophenyl stationary phase), and various infrared spectroscopy approaches (including GC‐sIR). Availability of detailed analytical data obtained from these novel APBT‐type stimulants may be useful to researchers and scientists in cases where forensic and clinical investigations are warranted.     

Syntheses,analytical and pharmacological characterizations of the ‘legal high’ 4‐[1‐(3‐methoxyphenyl)cyclohexyl]morpholine (3‐MeO‐PCMo) and analogues

New psychoactive substances (NPS) are commonly referred to as ‘research chemicals’, ‘designer drugs’ or ‘legal highs’. One NPS class is represented by dissociative anesthetics, which include analogues of the arylcyclohexylamine phencyclidine (PCP), ketamine and diphenidine. A recent addition to the NPS market was 4‐[1‐(3‐methoxyphenyl)cyclohexyl]morpholine (3‐MeO‐PCMo), a morpholine analogue of 3‐MeO‐PCP. Although suspected to have dissociative effects in users, information about its pharmacological profile is not available. From clinical and forensic perspectives, detailed analytical data are needed for identification, especially when facing the presence of positional isomers, as these are frequently unavailable commercially. This study presents the analytical and pharmacological characterization of 3‐MeO‐PCMo along with five additional analogues, namely the 2‐ and 4‐MeO‐PCMo isomers, 3,4‐methylenedioxy‐PCMo (3,4‐MD‐PCMo), 3‐Me‐PCMo and PCMo. All six arylcyclohexylmorpholines were synthesized and characterized using chromatographic, mass spectrometric and spectroscopic techniques. The three positional isomers could be differentiated and the identity of 3‐MeO‐PCMo obtained from an internet vendor was verified. All six compounds were also evaluated for affinity at 46 central nervous system receptors including the N‐methyl‐d ‐aspartate receptor (NMDAR), an important target for dissociative anesthetics such as PCP and ketamine. In vitro binding studies using (+)‐[3‐³H]‐MK‐801 in rat forebrain preparations revealed moderate affinity for NMDAR in the rank order of 3‐Me >3‐MeO > PCMo >3,4‐MD > 2‐MeO > 4‐MeO‐PCMo. 3‐MeO‐PCMo was found to have moderate affinity for NMDAR comparable to that of ketamine, and had an approximate 12‐fold lower affinity than PCP. These results support the anecdotal reports of dissociative effects from 3‐MeO‐PCMo in humans.     

Syntheses and analytical characterizations of N‐alkyl‐arylcyclohexylamines

The rise in new psychoactive substances that are available as 'research chemicals’ (RCs) remains a significant forensic and legislative challenge. A number of arylcyclohexylamines have attracted attention as RCs and continue to be encountered, including 3‐MeO‐PCP, 3‐MeO‐PCE and 3‐MeO‐PCPr. These compounds are commonly perceived as ketamine‐like dissociative substances and are believed to act predominantly via antagonism of the N‐methyl‐D‐aspartate (NMDA) receptor. To aid in the identification of newly emerging substances of abuse, the current studies were performed. The syntheses of fifteen N‐alkyl‐arylcyclohexylamines are described. Analytical characterizations were performed via gas chromatography and high performance liquid chromatography coupled to multiple forms of mass spectrometry as well as nuclear magnetic resonance spectroscopy, ultraviolet diode array detection and infrared spectroscopy. The series consisted of the N‐alkyl derivatives (N‐methyl, N‐ethyl, N‐propyl) of phenyl‐substituted and isomeric 2‐, 3‐ and 4‐methoxy phenylcyclohexylamines, as well as the N‐alkyl derivatives obtained from 3‐methylphenyl and 2‐thienyl moieties. In addition to the presentation of a range of previously unreported data, it was also found that positional isomers of aryl methoxyl‐substituted arylcyclohexylamines were readily distinguishable under a variety of analytical conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Preparation and characterization of the ‘research chemical’ diphenidine,its pyrrolidine analogue,and their 2,2‐diphenylethyl isomers

Substances with the diphenylethylamine nucleus represent a recent addition to the product catalog of dissociative agents sold as ‘research chemicals’ on the Internet. Diphenidine, i.e. 1‐(1,2‐diphenylethyl)piperidine (1,2‐DEP), is such an example but detailed analytical data are less abundant. The present study describes the synthesis of diphenidine and its most obvious isomer, 1‐(2,2‐diphenylethyl)piperidine (2,2‐DEP), in order to assess the ability to differentiate between them. Preparation and characterization were also extended to the two corresponding pyrrolidine analogues 1‐(1,2‐diphenylethyl)‐ and 1‐(2,2‐diphenylethyl)pyrrolidine, respectively. Analytical characterizations included high‐resolution electrospray mass spectrometry (HR‐ESI‐MS), liquid chromatography ESI‐MS/MS, gas chromatography ion trap electron and chemical ionization MS, nuclear magnetic resonance spectroscopy (NMR) and infrared spectroscopy. Differentiation between the two isomeric pairs was possible under GC‐(EI/CI)‐MS conditions and included the formation of distinct iminium ions, such as m/z 174 for 1,2‐DEP and m/z 98 for 2,2‐DEP, respectively. The pyrrolidine counterparts demonstrated similar phenomena including the expected mass difference of 14 Da due to the lack of one methylene unit in the ring. Two samples obtained from an Internet vendor provided confirmation that diphenidine was present in both samples, concurring with the product label. Finally, it was confirmed that diphenidine (30 μM) reduced N‐methyl‐D ‐aspartate‐mediated field excitatory postsynaptic potentials (NMDA‐fEPSPs) to a similar extent to that of ketamine (30 μM) when using rat hippocampal slices. The appearance of 1,2‐ diphenylethylamines appears to reflect the exploration of alternatives to arylcyclohexylamine‐type substances, such as methoxetamine, PCP and PCPy‐based analogues that also show NMDA receptor activity as demonstrated here for diphenidine. Copyright © 2014 John Wiley & Sons, Ltd.     

Lefetamine‐derived designer drugs N‐ethyl‐1,2‐diphenylethylamine (NEDPA) and N‐iso‐propyl‐1,2‐diphenylethylamine (NPDPA): Metabolism and detectability in rat urine using GC‐MS,LC‐MSn and LC‐HR‐MS/MS

N‐Ethyl‐1,2‐diphenylethylamine (NEDPA) and N‐iso‐propyl‐1,2‐diphenylethylamine (NPDPA) are two designer drugs, which were confiscated in Germany in 2008. Lefetamine (N,N‐dimethyl‐1,2‐diphenylethylamine, also named L‐SPA), the pharmaceutical lead of these designer drugs, is a controlled substance in many countries. The aim of the present work was to study the phase I and phase II metabolism of these drugs in rats and to check for their detectability in urine using the authors’ standard urine screening approaches (SUSA). For the elucidation of the metabolism, rat urine samples were worked up with and without enzymatic cleavage, separated and analyzed by gas chromatography‐mass spectrometry (GC‐MS) and liquid chromatography‐high resolution‐tandem mass spectrometry (LC‐HR‐MS/MS). According to the identified metabolites, the following metabolic pathways for NEDPA and NPDPA could be proposed: N‐dealkylation, mono‐ and bis‐hydroxylation of the benzyl ring followed by methylation of one of the two hydroxy groups, combinations of these steps, hydroxylation of the phenyl ring after N‐dealkylation, glucuronidation and sulfation of all hydroxylated metabolites. Application of a 0.3 mg/kg BW dose of NEDPA or NPDPA, corresponding to a common lefetamine single dose, could be monitored in rat urine using the authors’ GC‐MS and LC‐MSⁿ SUSA. However, only the metabolites could be detected, namely N‐deethyl‐NEDPA, N‐deethyl‐hydroxy‐NEDPA, hydroxy‐NEDPA, and hydroxy‐methoxy‐NEDPA or N‐de‐iso‐propyl‐NPDPA, N‐de‐iso‐propyl‐hydroxy‐NPDPA, and hydroxy‐NPDPA. Assuming similar kinetics, an intake of these drugs should also be detectable in human urine. Copyright © 2014 John Wiley & Sons, Ltd.     

Design and syntheses of methyl 2‐methyl‐2‐[2‐(4‐benzoyl‐5‐phenyl‐7‐halo‐2‐azabicyclo[4.1.0]hept‐3‐ene)]acetates: novel inhibitors of cyclooxygenase‐2 (COX‐2) with analgesic‐antiinflammatory activity

A group of methyl 2‐methyl‐2‐[2‐(4‐benzoyl‐5‐phenyl‐7‐halo‐2‐azabicyclo[4.1.0]hept‐3‐ene)]acetates ( 10–15 ), and the related acetamide derivative ( 16 ), that possess a variety of C‐7 substituents (Br, Cl, F, H), were designed for evaluation as analgesic‐antiinflammatory agents. The effect of the C‐7 substituent(s) and the nature of the acetic acid ester (R¹ = Ome) or acetamide (R¹ = NH₂) moiety on analgesic activity was determined using a 4% NaCl‐induced abdominal constriction assay. Compounds 10–16 inhibited writhing by 36–82%, relative to the reference drugs aspirin (58% inhibition) and celecoxib (62% inhibition). The nature of the C‐7 substituents was a determinant of analgesic activity in the 7,7‐dihalo group of compounds where the relative activity profile was 7‐Cl₂ > 7‐Br₂ > 7‐F₂ > 7‐Cl,7‐F, and for 7‐monohalo compounds where the potency order was 7‐Br > 7‐Cl. Elaboration of the 7,7‐dibromo methyl acetate ester ( 10 ) to the corresponding acetamide derivative ( 16 ) enhanced analgesic activity. The nature of the 7‐halo substituent(s) in the 7,7‐dihalo group of compounds was a determinant of antiinflammatory activity, determined using the carrageenan‐induced rat paw edema assay, where the relative potency order was 7‐Br₂ > 7‐Cl₂ > 7‐F₂ > 7‐Cl,7‐F. The most potent 7,7‐dibromo compound ( 10 ) inhibited inflammation by 62%, relative to the reference drug ibuprofen (44%), and 10 inhibited COX‐2 (IC₅₀ = 26.4 μM) and COX‐1 (IC₅₀ = 227 μM) for a COX‐2 selectivity index of 8.6. Docking 10 in the active site of human COX‐2 showed it binds in the center of the COX‐2 binding site with the C‐5 phenyl ring oriented toward the acetylation site (Ser⁵³⁰), and the phenyl group of the C‐4 benzoyl moiety oriented in the vicinity of the COX‐2 secondary binding pocket near Val⁵²³. Drug Dev. Res. 49:75–84, 2000. © 2000 Wiley‐Liss, Inc.     

Synthesis of labelled N‐(4‐hydroxy‐[14C(U)]phenyl)‐2‐[2,3‐dihydro‐3‐oxo‐l,2‐benzisothiazol‐2‐yl‐1,1‐dioxide]acetamide

The amidation of 2‐[1,1‐dioxide‐3‐oxo‐1,2‐benzisothiazole‐2(3H)‐yl] acetyl chloride with carbon‐14‐labelled 4‐amino‐[¹⁴C(U)]phenol in NaOAc‐HOAc buffer solution at ?10°C gave N‐(4‐hydroxy‐[¹⁴C(U)]phenyl)‐2‐[2,3‐dihydro‐3‐oxo‐1,2‐benziso‐thiazol‐2‐yl‐1,1‐dioxide]acetamide in 82% yield. Subsequent hydrolysis with aqueous 0.5 N NaOH solution afforded the ring opened product N‐(4‐hydroxy‐[¹⁴C(U)]‐phenyl)‐2‐[2‐carboxy‐phenylsulfonamido]acetamide in 80% yield. Copyright © 2005 John Wiley & Sons, Ltd.     

N‐[9‐(ortho‐Fluorobenzyl)‐2‐Phenyl‐8‐Azapurin‐6‐yl]‐Amides as Potent and Selective Ligands for A1 Adenosine Receptors

A series of N‐[9‐(ortho‐fluorobenzyl)‐2‐phenyl‐8‐azapurin‐6‐yl]‐amides were synthesized and tested for their affinity toward A₁, A_2A, and A₃ adenosine receptor subtypes. Biological results demonstrated that the introduction of a fluorine atom at the ortho position of the 9‐benzyl group generally enhanced affinity toward A₁ subtype and did not significantly affect A_2A and A₃ affinity. Very interesting is the compound bearing a meta‐fluorophenyl substituent on the carbonyl carbon of the amide group, which shows significantly high A₁/A_2A‐A₃ selectivity. Compounds of this new series, together with the previously published analogs without the fluorine atom on the 9‐benzyl group, constituted the starting dataset for the development of QSAR models. The models obtained were able to rationally describe the affinity trends resulting from biological testing and to enable investigation of the role of different substituents on the 8‐azapurine scaffold, as well as the influence of the newly introduced fluorine atom on the benzyl moiety. The said QSAR models can also assist in the design of new compounds selectively active on A₁ adenosine receptors. Furthermore, a molecular docking study was carried out to assess hypothetical binding mode of N‐[9‐(ortho‐fluorobenzyl)‐2‐phenyl‐8‐azapurin‐6‐yl]‐amides to A₁ adenosine receptors.     

Analytical characterization of three hallucinogenic N‐(2‐methoxy)benzyl derivatives of the 2C‐series of phenethylamine drugs

This publication reports analytical properties of three new hallucinogenic substances identified in blotter papers seized from the drug market, namely 25D‐NBOMe [2‐(2,5‐dimethoxy‐4‐methylphenyl)‐N‐(2‐methoxybenzyl)ethanamine], 25E‐NBOMe [2‐(4‐ethyl‐2,5‐dimethoxyphenyl)‐N‐(2‐methoxybenzyl)ethanamine] and 25G‐NBOMe [2‐(2,5‐dimethoxy‐3,4‐dimethylphenyl)‐N‐(2‐methoxybenzyl)ethanamine]. These substances are N‐(2‐methoxy)benzyl derivatives of the 2C‐series of phenethylamine drugs. The applied procedure covered a variety of analytical methods, including gas chromatography with electron impact mass spectrometry (GC‐EI‐MS; without derivatization and after derivatization with trifluoroacetic anhydride (TFAA)), liquid chromatography‐electrospray ionization‐quadrupole time of flight mass spectrometry (LC‐ESI‐QTOF‐MS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR), which made it possible to identify the active components unequivocally. The GC‐MS spectra of analyzed compounds were very similar, with dominant ions observed at m/z = 150, 121, and 91. The remaining ions were analogous to those observed for parent substances, namely 2C‐D, 2C‐E, 2C‐G, but their intensities were low. Derivatization allowed determination of molecular masses of the investigated substances. Their exact masses and chemical formulas were confirmed by LC‐QTOF‐MS experiments and the fragmentation patterns of these compounds following ESI were determined. The tandem mass spectrometry (MS/MS) experiments confirmed that the studied substances were N‐(2‐methoxy)benzyl derivatives of the 2C‐series compounds. Final elucidation of the structures was performed by NMR spectroscopy. The substances were also characterized by FTIR spectroscopy to corroborate the identity of the compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and Selective Inhibitory Activity Against Human COX‐1 of Novel 1‐(4‐Substituted‐thiazol‐2‐yl)‐3,5‐di(hetero)aryl‐pyrazoline Derivatives

Novel 1‐(4‐ethyl carboxylate‐thiazol‐2‐yl)‐3,5‐di(hetero)aryl‐2‐pyrazoline derivatives were obtained by reacting 3,5‐di(hetero)aryl‐1‐thiocarbamoyl‐2‐pyrazolines with the ethyl ester of α‐bromo‐pyruvic acid. The synthesized compounds were confirmed by spectroscopic data and assayed to evaluate their in vitro ability to inhibit both isoforms of human cyclooxygenase (hCOX). Some derivatives (compounds 5 , 6 , 13 , 16 , and 17 ) displayed promising selectivity against hCOX‐1 in the micromolar range and were shown to have a selectivity index similar or better than the reference drugs (indometacin, diclofenac). The introduction of a phenyl or a 4‐F‐phenyl ring on the C5 associated with a 4‐substituted phenyl or a heteroaryl group on the C3 of (4‐substituted‐thiazol‐2‐yl)pyrazoline derivatives improved the activity against hCOX‐1. Thanks to these preliminary results it could be possible to extend our knowledge of the pharmacophoric requirements for the discovery of new pyrazoline‐based hCOX‐1 inhibitors.     

AMT (3‐(2‐aminopropyl)indole) and 5‐IT (5‐(2‐aminopropyl)indole): an analytical challenge and implications for forensic analysis

5‐(2‐Aminopropyl)indole (5‐IT) and 3‐(2‐aminopropyl)indole (α‐methyltryptamine, AMT) are isomeric substances and their differentiation can be a challenge under routine analytical conditions, especially when reference material is unavailable. 5‐IT represents a very recent addition to the battery of new psychoactive substances that are commercially available from online retailers. This report illustrates how subtle differences observed under mass spectral and UV conditions can help to facilitate the differentiation between the two isomers. Analyses included ¹ H and ¹³C NMR, GC‐EI/CI ion trap MS, applications of several U/HPLC‐DAD and HPLC‐MS methods. Investigations currently underway also highlight the confirmation that AMT was detected in a number of fatal intoxications. These findings also demonstrate that there is a potential risk of misidentification when dealing with both substances. Copyright © 2012 John Wiley & Sons, Ltd.     

18F‐labelling of a potent nonpeptide CCR1 antagonist: synthesis of 1‐(5‐chloro‐2‐{2‐[(2R)‐4‐(4‐[18F]fluorobenzyl)‐2‐methylpiperazin‐1‐yl]‐2‐oxoethoxy}phenyl)urea in an automated module

The synthesis of 1‐(5‐chloro‐2‐{2‐[(2R)‐4‐(4‐[¹⁸F]fluorobenzyl)‐2‐methylpiperazin‐1‐yl]‐2‐oxoethoxy}phenyl)urea ( [¹⁸F]4 ), a potent nonpeptide CCR1 antagonist, is described as a module‐assisted two‐step one‐pot procedure. The final product was obtained utilizing the reductive amination of the formed 4‐[¹⁸F]fluorobenzaldehyde ( 2 ) with a piperazine derivative 3 and sodium cyanoborohydride. After HPLC purification of the final product [¹⁸F]4 , its solid phase extraction, formulation and sterile filtration, the isolated (not decay‐corrected) radiochemical yields of [¹⁸F]4 were between 7 and 13% (n=28). The time of the entire manufacturing process did not exceed 95 min. The radiochemical purity of [¹⁸F]4 was higher than 95%, the chemical purity ?60% and the enantiomeric purity >99.5%. The specific radioactivity was in the range of 59–226 GBq/µmol at starting radioactivities of 23.6–65.0 GBq [¹⁸F]fluoride. Copyright © 2006 John Wiley & Sons, Ltd.     

Design,syntheses, and evaluation of 2,3‐diphenylcycloprop‐2‐en‐1‐ones and oxime derivatives as potential cyclooxygenase‐2 (COX‐2) inhibitors with analgesic‐antiinflammatory activity

A group of 2,3‐diphenylcycloprop‐2‐enes having a variety of substituents at the para‐position of the C‐2 phenyl ring (H, F), and C‐3 phenyl ring (H, F, SMe, SOMe, SO₂Me), in conjunction with either a C‐1 carbonyl, oxime, oxime acetate, benzoyl hydrazone, or hydrogen substituent were synthesized for in vivo evaluation as analgesic and antiinflammatory (AI) agents, and as potential selective cyclooxygenase‐2 (COX‐2) inhibitors. This group of cycloprop‐2‐ene compounds exhibited significant analgesic activity, since 4% NaCl‐induced abdominal constriction was reduced by 43–90% at 30 min, and 41–100% at 60 min, after drug administration relative to the reference drugs aspirin and celecoxib (58% and 32% inhibition at 30 min after drug administration) for a 50 mg/kg intraperitoneal dose. AI activities, determined using the carrageenan‐induced rat paw edema assay, showed that this class of cycloprop‐2‐ene compounds exhibited AI activities in the inactive‐to‐modest activity range (0–26% inhibition) for a 50 mg/kg oral dose. The AI potency order for a group of 2,3‐diphenylcycloprop‐2‐enes with respect to the C‐1 substituent was oxime>hydrogen>carbonyl>benzoyl hydrazone. 2,3‐Diphenylcycloprop‐2‐en‐1‐one oxime ( 20 ) was the most active AI agent, inducing a 26% reduction in inflammation, relative to the reference drugs ibuprofen and celecoxib, which showed 52% and 58% reductions in inflammation, at 5 h after drug administration. In vitro COX‐1 and COX‐2 inhibition studies showed that 2,3‐diphenylcycloprop‐2‐en‐1‐one oxime ( 20 ) is a selective COX‐2 inhibitor (COX‐1 IC₅₀>100 μM; COX‐2 IC₅₀=2.94 μM; COX‐2 selectivity index>34). A molecular modeling study that docked the oxime ( 20 ) in the active site of the human COX‐2 isozyme showed that it binds in the vicinity of the mouth of the COX‐2 binding site with the O‐atom of the oxime (=N–OH) moiety separated from the NH₂ group of Arg¹²⁰ by about 3.65 Å. This orientation of the oxime compound ( 20 ) in the COX‐2 binding site could be due to a potentially strong ionic interaction between the =NOH oxime moiety and the guanidinium moiety of Arg¹²⁰. Drug Dev. Res. 57:6–17, 2002. © 2002 Wiley‐Liss, Inc.     

Syntheses of 5‐(2‐radiohaloethyl)‐ and 5‐(2‐radiohalovinyl)‐2′‐ deoxyuridines. Novel types of radiotracer for monitoring cancer gene therapy with PET

Syntheses of 5‐(2‐[¹⁸F]fluoroethyl)‐ ( 1 ), 5‐(2‐[⁸⁰Br]bromoethyl)‐ ( 2 ), un‐deprotected (E)‐5‐(2‐[¹⁸F]fluorovinyl)‐ ( 3 ) and (E)‐5‐(2‐[⁸⁰Br]bromovinyl)‐2′‐deoxyuridines ( 4 ) as the tracers for monitoring cancer gene therapy with positron emission tomography were described. Decay corrected radiochemical yield and synthesis time including labeling and HPLC purification from end of bombardment for 1 was 9.5% and 2 hours, respectively; yield and time for 2 was 16% and 2 hours, respectively. Chemical (approximate to radiochemical) yield and time for synthesis of 3 was 7.5% and 7 minutes, respectively. Radiochemical yield and synthesis time including labeling and HPLC purification of an analytical sample of 4 was 60% and 30 minutes, respectively. Both 2 and 4 received the side reactions during HPLC purification, i.e. ring closure and cleavage of glycosidic bond, respectively. Application of 2 and 4 needed to be confirmed by in vitro or in vivo experiments. Radiochemical yield of 1 could be optimized by employing a modified protocol for preparation of its precursor. The preparation of fluorovinyl counterparts had demonstrated the potential utility of the stannane, 3‐tolyl‐3′,5′‐di‐O‐acetyl‐(E)‐5‐(2‐stannylvinyl)‐2′‐deoxyuridine 7 . Copyright © 2003 John Wiley & Sons, Ltd.     

Preparation and in‐vitro Evaluation of 4‐Benzylsulfanylpyridine‐2‐carbohydrazides as Potential Antituberculosis Agents

A set of 4‐benzylsulfanylpyridine‐2‐carbohydrazides was synthesized and evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, non‐tuberculous mycobacteria, and multidrug‐resistant M. tuberculosis. The activities expressed as the minimum inhibitory concentration (MIC) fall into a range of 2 to 125 μmol/L, most often 4 to 32 μmol/L. The results revealed that the substituents on the benzyl moiety do not influence the antimycobacterial efficacy. The substances exhibited similar activities against sensitive and resistant strains of M. tuberculosis. Furthermore, compounds show low antiproliferative effect and cytotoxicity.     

Synthesis of 2‐(methylsulfonyl)‐5‐(4‐(methylsulfonyl) phenyl)‐4‐phenyl‐1H‐[5‐14C]imidazole,a selective COX‐2 inhibitor,via asymmetrical benzoins

4,5‐Diarylimidazoles labeled with carbon‐14 in the 5‐position of the imidazole ring were prepared as a part of three‐step sequence from 2‐hydroxy‐1‐(4‐(methylthio)phenyl)‐2‐phenyl[1‐¹⁴C]ethanone as a key synthetic intermediate which has been synthesized from potassium [¹⁴C]cyanide.     

Design,Synthesis, and Antitumor Activity of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones

A series of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones ( C1 – C35 ) were designed and synthesized, and the structures of compounds (Z)‐ C27 and (Z)‐ C29 were confirmed by single‐crystal X‐ray diffraction. The antitumor activities of these novel compounds against cervical cancer (HeLa), lung cancer (A549), and breast cancer (MCF‐7) cell lines were evaluated in vitro. Majority of the title compounds exhibited strong antitumor activities and were much more promising than the positive control Taxol, which were also accompanied by lower cytotoxicity to normal cells. In particular, compounds (E,Z)‐ C24 exhibited the most consistent potent activities against three neoplastic cells with IC₅₀ values ranging from 3.2 to 7.1 μm . Further researches demonstrated that compounds (E,Z)‐ C24 could induce cell apoptosis and arrest cell cycle at the G2/M and S phases. Meanwhile, the structure–activity relationship between the configurations and cytotoxicity of the compounds was also investigated.     

Synthesis,analytical characterization,and monoamine transporter activity of the new psychoactive substance 4‐methylphenmetrazine (4‐MPM), with differentiation from its ortho‐ and meta‐ positional isomers

The availability of new psychoactive substances (NPS) on the recreational drug market continues to create challenges for scientists in the forensic, clinical and toxicology fields. Phenmetrazine (3‐methyl‐2‐phenylmorpholine) and an array of its analogs form a class of psychostimulants that are well documented in the patent and scientific literature. The present study reports on two phenmetrazine analogs that have been encountered on the NPS market following the introduction of 3‐fluorophenmetrazine (3‐FPM), namely 4‐methylphenmetrazine (4‐MPM), and 3‐methylphenmetrazine (3‐MPM). This study describes the syntheses, analytical characterization, and pharmacological evaluation of the positional isomers of MPM. Analytical characterizations employed various chromatographic, spectroscopic, and mass spectrometric platforms. Pharmacological studies were conducted to assess whether MPM isomers might display stimulant‐like effects similar to the parent compound phenmetrazine. The isomers were tested for their ability to inhibit uptake or stimulate release of tritiated substrates at dopamine, norepinephrine and serotonin transporters using in vitro transporter assays in rat brain synaptosomes. The analytical characterization of three vendor samples revealed the presence of 4‐MPM in two of the samples and 3‐MPM in the third sample, which agreed with the product label. The pharmacological findings suggest that 2‐MPM and 3‐MPM will exhibit stimulant properties similar to the parent compound phenmetrazine, whereas 4‐MPM may display entactogen properties more similar to 3,4‐methylenedioxymethamphetamine (MDMA). The combination of test purchases, analytical characterization, targeted organic synthesis, and pharmacological evaluation of NPS and their isomers is an effective approach for the provision of data on these substances as they emerge in the marketplace.     

N3‐Substituted thymidine analogues III: radiosynthesis of N3‐[(4‐[18F]fluoromethyl‐phenyl)butyl]thymidine ([18F]‐FMPBT) and N3‐[(4‐[18F]fluoromethyl‐phenyl)pentyl] thymidine ([18F]‐FMPPT) for PET

Radiosyntheses of two N³‐substituted thymidine analogues, N³‐[(4[¹⁸F]fluoromethyl‐phenyl)butyl]thymidine ([¹⁸F]‐FMPBT) and N³‐[(4[¹⁸F]fluoromethyl‐phenyl)pentyl]thymidine ([¹⁸F]‐FMPPT), are reported. The precursor compounds 9 and 10 were synthesized in six steps and the standard compounds 13 and 14 were synthesized from these precursors. For radiosynthesis, compounds 9 and 10 were fluorinated with n‐Bu₄N[¹⁸F] to produce [¹⁸F]‐ 11 and [¹⁸F]‐ 12 , which by acid hydrolysis yielded [¹⁸F]‐ 13 and [¹⁸F]‐ 14 , respectively. The crude products were purified by high‐performance liquid chromatography to obtain [¹⁸F]‐FMPBT and [¹⁸F]‐FMPPT. The average decay‐corrected radiochemical yield for [¹⁸F]‐ 13 was 15% in five runs, and that for [¹⁸F]‐ 14 was 10% in four runs. The radiochemical purity was >99% and the specific activity was >74 GBq/µmol at the end of synthesis. The synthesis time was 80–90 min from the end of bombardment. Copyright © 2007 John Wiley & Sons, Ltd.