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There has been a rapid increase over the last decade in the appearance of new non-controlled psychoactive substances. Minor changes in the chemical structures of these compounds, such as the extension of an alkyl residue or replacement of a single substituent, are regularly made to avoid regulatory control, leading to the manufacture of many new potentially dangerous drugs. Bromoamphetamine analogs (bromoamphetamine [Br-AP] and bromomethamphetamine (Br-MA]) are ring-substituted amphetamines that can behave as stimulants, as well as exhibiting inhibitory activity towards monoamine oxidases in the same way as amphetamines. Gas chromatography–tandem mass spectrometry (GC–MS–MS) was used in this study to differentiate ring-substituted bromoamphetamine analogs. Free bases, trifluoroacetyl derivatives, and trimethylsilyl (TMS) derivatives of six analytes were successfully separated using DB-1ms and DB-5ms columns. Electron ionization MS–MS analysis of the TMS derivatives allowed for the differentiation of three regioisomers. TMS derivatives of 2-positional isomers provided significant product ions. The spectral patterns of 3- and 4-positional isomers were different. Chemical ionization MS–MS analysis of free bases for [M+H–HBr]+ ions at m/z 134 and 148 allowed for differentiation of the regioisomers. The spectra of 2-positional isomers contained characteristic product ions formed by dehydrogenation at m/z 132 and m/z 146 for 2Br-AP and 2Br-MA, respectively. The spectra of 3-positional isomers contained α-cleaved iminium cations as the base peaks. The spectra of 4-positional isomers showed a tropylium cation at m/z 91 as the base peak. These results demonstrate that GC–MS–MS can be used for the differentiation of regioisomeric Br-AP analogs in forensic practice.

In recent years, a large number of clandestinely synthesized new psychoactive substances with high structural variety have been detected in forensic samples. Analytical differentiation of regioisomers is a significant issue in forensic drug analysis, because, in most cases, legal controls are placed on only one or two of the conceivable isomers. In this study, gas chromatography–tandem mass spectrometry (GC–MS–MS) was used to differentiate the regioisomers of chloroamphetamine analogs (chloroamphetamines and chloromethamphetamines) synthesized in the authors′ laboratories. Free bases, trifluoroacetyl derivatives, and trimethylsilyl derivatives were subjected to GC–MS–MS using DB-1ms, DB-5ms, and DB-17ms capillary columns, respectively. The regioisomers of chloroamphetamine analogs in all forms were well separated on the DB-5ms column. The electron ionization mass spectra of the chloroamphetamine analogs gave very little structural information for differentiation among these analogs, even after trifluoroacetyl and trimethylsilyl derivatization of the analytes. Characteristic product ions of the 2-positional isomers were observed by electron ionization-MS–MS. In contrast, chemical ionization-MS–MS of the free bases provided more structural information about chloride position on the aromatic ring when [M+H–HCl]+ was selected as a precursor ion. The results suggest that a combination of chromatographic analysis and MS–MS supports differentiation for regioisomers of chloroamphetamine analogs.

A portable near infrared spectrometer was applied to the presumptive identification of psychotropic drugs based on library searching. Data-treatment methods (mathematical pretreatment and library search algorithm) were examined on the basis of differentiation ability. The optimized mathematical pretreatment was a standard normal variate followed by the 2nd derivative. The correlation coefficient showed the best differentiation ability in the library search algorithms. Optimized data-treatment was effective for minimizing the effect of particle size on identification. The optimized data-treatment methods were validated by the spectra of psychotropic substances (n=120). Identification criteria for the psychotropic drugs were decided on the basis of the results of the validation. As a consequence, 8 out of 11 forensic samples containing psychoactive substances were able to be positively identified. Thus, the portable near infrared spectrometer with optimized data-treatment processing is a useful tool for rapid screening and presumptive identification of seized materials.

In recent years, a large number of tryptamine-based designer drugs have been encountered in forensic samples. We have developed simultaneous analytical methods for 14 tryptamine analogues using gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS–MS). Trimethylsilyl (TMS) derivatives of the analytes were separated on a DB-1ms column within 15 min. The structural isomers could be differentiated by electron ionization GC–MS. LC–MS–MS with a C18 column could separate structural isomers of tryptamines except for a combination of 5-methoxy-N,N-diethyltryptamine and 5-methoxy-N-methyl-N-isopropyltryptamine. Higher collision energy gave different product ion spectra between the structural isomers. The results indicate that GC–MS is the first choice for identification of tryptamines, preferably after TMS derivatization, and LC–MS–MS can be used as a complementary approach for the unequivocal differentiation of tryptamine isomers.

In recent years, a large number of clandestinely produced controlled-substance analogs (designer drugs) of amphetamine with high structural variety have been detected in forensic samples. Analytical differentiation of regioisomers is a significant issue in forensic drug analysis because, in most cases, legal controls are placed only on one or two of the three isomers. In this study, we used gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the differentiation of regioisomers of fluoroamphetamine analogs (fluoroamphetamines and fluoromethamphetamines), which were synthesized in our laboratories. Free bases and their acylated and silylated derivatives were subjected to GC–MS analysis using DB-1ms, DB-5ms, and DB-17ms capillary columns. The separation of free bases was incomplete on all columns. Trifluoroacetyl derivatives of 3- and 4-positional isomers showed slight separation on DB-1ms and DB-5ms. On the other hand, trimethylsilyl derivatization enabled baseline separation of six fluoroamphetamine analogs on DB-1ms and DB-5ms columns, which was sufficient for unequivocal identification. For LC–MS/MS, a pentafluorophenyl column was able to separate six regioisomeric fluoroamphetamine analogs but a conventional C18 column could not achieve separation between 3- and 4-positional isomers. These results show that a suitable choice of derivatization and analytical columns allows the differentiation of regioisomeric fluoroamphetamine analogs.

A new and convenient method for the preparation of 3-substituted benzo[b]thiophenes was developed. α-Substituted 2-(1-phenylethylthio)styrenes, which could easily be prepared from 2-mercaptophenyl ...

This is the first report on development of a library search-based screening system for 3,4-methylenedioxymethamphetamine (MDMA) in ecstasy tablets using a portable near-infrared (NIR) spectrometer. The spectrum library consisted of spectra originating from standard substances as well as mixtures of MDMA hydrochloride (MDMA-HCl) and diluents. The raw NIR spectra were mathematically pretreated, and then, a library search was performed using correlation coefficient. To enhance the discrimination ability, the wavelength used for the library search was limited. Mixtures of MDMA-HCl and diluents were used to decide criteria to judge MDMA-positive or MDMA-negative. Confiscated MDMA tablets and medicinal tablets were used for performance check of the criteria. Twenty-two of 27 MDMA tablets were truly judged as MDMA-positive. Five false-negative results may be caused by compounds not included in the library. No false-positive results were obtained for medicinal tablets. This system will be a useful tool for on-site screening of MDMA tablets.

A convenient synthetic method for 1-aryl-1H-indole derivatives has been developed. 2-(Arylamino)-α-methylstyrene derivatives were treated with iodine in the presence of sodium hydrogencarbonate to ...

The iodoamination of o-(acylamino)styrene derivatives using iodine and sodium hydrogencarbonate, producing 7-acyl-8-iodomethylbicyclo[4.2.0]-7-azaoct-1,3,5-triene [1-acyl-2-(iodomethyl)benzazetine]...

2,4-Disubstituted quinolines have been synthesized by reactions of o-isocyano-β-methoxystyrenes, which can be easily prepared from commercially available o-aminophenyl ketones in three steps, with alkyl(or aryl)lithiums in generally good yields. Subsequently, o-isocyano-β-methoxystyrenes have also proved to react efficiently with lithium dialkylamides to afford the corresponding 4-substituted N,N-dialkylquinolin-2-amines in satisfactory yields.

4-Aryl-2-methyl(or phenyl)thio-2H-1-benzothiopyrans have been prepared in satisfactory yields from the corresponding 1-(1-aryl-2-methoxyethenyl)-2-{[methyl(or phenyl)thiomethyl]thio}benzenes via li...

The first general method for the synthesis of 4H-1,3-benzodioxin-2-one derivatives has been developed. Treatment of t-butyl 2-vinylphenyl carbonates with iodine in the presence of sodium hydrogencarbonate gave 4-iodomethyl-4H-1,3-benzodioxin-2-one derivatives in moderate to good yields. These iodides were reduced with tributyltin hydride to give the corresponding 4-methyl-4H-1,3-benzodioxin-2-one derivatives.

A new and convenient method for the preparation of 3-substituted benzo[b]thiophenes was developed. α-Substituted 2-(1-phenylethylthio)styrenes, which could easily be prepared from 2-mercaptophenyl ...

It has been found that halogen-lithium exchange between α-substituted 2-bromo-β-methoxystyrene derivatives and n-butyllithium generates α-substituted 2-lithio-β-methoxystyrene derivatives, which successfully react with a range of nitriles to afford the corresponding 1,4-disubstituted isoquinolines in reasonable yields.

The first general method for the synthesis of 4H-1,3-benzodioxin-2-one derivatives has been developed. Treatment of t-butyl 2-vinylphenyl carbonates with iodine in the presence of sodium hydrogencarbonate gave 4-iodomethyl-4H-1,3-benzodioxin-2-one derivatives in moderate to good yields. These iodides were reduced with tributyltin hydride to give the corresponding 4-methyl-4H-1,3-benzodioxin-2-one derivatives.

2,4-Disubstituted quinolines have been synthesized by reactions of o-isocyano-β-methoxystyrenes, which can be easily prepared from commercially available o-aminophenyl ketones in three steps, with alkyl(or aryl)lithiums in generally good yields. Subsequently, o-isocyano-β-methoxystyrenes have also proved to react efficiently with lithium dialkylamides to afford the corresponding 4-substituted N,N-dialkylquinolin-2-amines in satisfactory yields.

Reactions of 3-acyl-1,2-naphthoquinones with ethyl mercaptoacetate followed by protection of the resulting hydroxyl groups and thiophene ring formation using 1-trimethylsilylimidazole, deprotection with hydrochloric acid,and oxidation with cerium(lV) ammonium nitrate (CAN) gave, in one-pot, the title thienonaphthoquinone derivatives in moderate to good yields.

4,7-Dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylates (1) underwent regioselective acylation at the 5-position with a range of aldehydes under irradiation to give the corresponding 5-acyl-4,7-dihydroxybenzo[b]thiophene-2-carboxylates (2), which were then oxidized with Ag 2 O to afford 5-acyl-4,7-dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylates (3 ). These acylated benzothiophenquinone derivatives were transformed in one-pot to 4,8-dioxo-4,8-dihydrobenzo[1,2-b:5,4-b']dithiophene-2,6-dicarboxylates (5) by treatment with mercaptoacetates, followed by 1-trimethylsilylimidazole-mediated cyclization and cerium(IV) ammonium nitrate (CAN) oxidation.