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PubMed1998

Effects of various anionic chiral selectors on the capillary electrophoresis separation of chiral phenethylamines and achiral neutral impurities present in illicit methamphetamine.

In this study, various anionic chiral selectors were investigated for the capillary electrophoresis (CE) separation of six chiral phenethylamines and three achiral neutral impurities which are commonly identified in illicit methamphetamine. Analyses were carried out at pH 8 (high osmotic flow) with untreated capillaries using 25 mM chiral surfactant or 10 mM charged cyclodextrin. The chiral selectors included the micelle (R)-N-dodecoxycarbonylvaline (EnantioSelect (R)-Val-1) (ES) and the cyclodextrins sulfobutyl(IV)-ether-beta-cyclodextrin (SBE(IV)-beta-CD) (BSB4), SBE(VII)-beta-CD (BSB7), SBE(XII)-beta-CD (BSB 12), SBE(IV)-gamma-CD (GSB-4), SBE(VII)-gamma-CD (GSB-7), sulfated(XI)-alpha-cyclodextrin (SU(XI)-alpha-CD (AS11), SU(VII)-beta-CD (BS7), SU(XII)-beta-CD (BS12) and SU(XIII)-beta-CD (GS13). Enantiomeric and achiral selectivity strongly depends on the size of the CD, the average degree of substitution, and the type of substitution. ES exhibits good performance for the neutral solutes, but exhibits enantiomeric selectivity only for the alpha-hydroxyphenethylamines. GS13 provides the best overall enantiomeric selectivity. All fifteen solutes related to methamphetamine are simultaneously separated using BSB7.

Anions↗

PubMed1980

Cactus alkaloids XLII: 3,4-dimethoxy-beta-phenethylamine and heliamine from the Mexican cereoid Backebergia militaris.

Backebergia militaris (Andot) Bravo ex Sánchez Mejorada yielded alkaloid crystals from a fractionated ethanol extract of only 20 g of plant material. The alkaloid was identified as heliamine (6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) hydrochloride. A second alkaloid, 3,4-dimethoxy-beta-phenethylamine hydrochloride, was crystallized after preparative TLC of the mother liquors. Both compounds were isolated previously from other cactus species.

Alkaloids↗

PubMed1984

alpha-Phenyl-beta-(3,4-dimethoxy)phenethylamines: novel inhibitors of choline acetyltransferase from Torpedo electric organ.

Some derivatives of alpha-phenyl-beta-(3,4-dimethoxy)phenethylamine that might bear a certain conformational resemblance to choline were prepared. The in vitro inhibition of choline acetyltransferase from Torpedo electric organ was investigated. These compounds gave variable degrees of inhibition; the most potent inhibitor was, N,N,N,-trimethyl-alpha-phenyl-beta-(3,4-dimethoxy)phenethylammonium++ + iodide, with an I50 of 1.3 X 10(-5) M. The inhibition of choline acetyltransferase from Spodoptera littoralis larval brains was also determined for comparative study. The aforementioned compound has an I50 of 9 X 10(-6) M on choline acetyltransferase from this source.

Animals↗

PubMed1978

Single dose and cross tolerance studies of beta-phenethylamine, d-amphetamine and LSD in the chronic spinal dog.

The effects of beta-phenethylamine (PEA), d-amphetamine and LSD were studied on spinal reflexes, autonomic signs, and behavior in the non-tolerant and LSD tolerant (30 microgram/kg/day) chronic spinal dog. LSD (10 microgram/kg) facilitated the flexor reflex, produced the stepping reflex, increased respiration, pulse rate and temperature, slightly dilated pupils and produced whining, tracking and restlessness. Direct tolerance developed to all of these effects except temperature. PEA (0.8 mg/kg/min infused for 12 min) and amphetamine (3.2 mg/kg) facilitated the flexor reflex, increased respiration, temperature and the skin twitch reflex latency, caused a marked mydriasis, retracted the nictitating membrane and produced restlessness and stereotypic head movements. PEA but not amphetamine elicited stepping, and only amphetamine consistently slowed heart rate. No cross tolerance to the physiologic or behavioral effects of amphetamine was observed. Partial tolerance developed only to the actions of PEA on the stepping reflex and the nictitating membrane. The single dose effects and the lack of cross tolerance to amphetamine and PEA suggest modes of action different from LSD. PEA has some actions which differ from those of amphetamine.

Amphetamines↗

PubMed1982

Structure activity correlations in the inhibition of brain synaptosomal 3H-norepinephrine uptake by phenethylamine analogs. The role of alpha-alkyl side chain and methoxyl ring substitutions.

alpha-Ethylphenethylamine proved to be a weaker inhibitor of rat brain synaptosomal [3H]norepinephrine ([3H]NE) uptake than amphetamine, while 2-amino-tetralin and 2-amino-1,2-dihydronaphtalene, compounds in which the alpha-side chain ethyl group is tied to the aromatic ring have a similar inhibiting potency as amphetamine. Hallucinogenic polymethoxy substituted phenethylamine analogs have very low inhibitory potencies indicating that inhibition of NE-reuptake in brain noradrenergic neurons is not associated with the drug-induced hallucinogenic syndrome.

Amphetamine↗

PubMed1986

Direct comparison of hallucinogenic phenethylamines and D-amphetamine on dorsal raphe neurons.

We compared the effects of the hallucinogens 2,5-dimethoxy-4-methylamphetamine (DOM), mescaline and the simulant D-amphetamine, applied by microiontophoresis to rat dorsal raphe (DR) units. DR neuron firing rate was relatively insensitive to DOM and unaffected by mescaline, but was clearly inhibited by D-amphetamine. Intravenous DOM usually inhibited, but this effect was correlated with blood pressure changes; i.v. D-amphetamine produced inconsistent responses. These results suggest that most of the effects seen on i.v. administration of phenethylamines are not mediated directly on the serotonergic cell.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed1988

Alpha-adrenoceptor occupancy by N,N-dimethyl-2-bromo-2-phenethylamine hydrobromide (DMPEA) in rat vas deferens.

The effects of N,N-dimethyl-2-bromo-2-phenethylamine hydrobromide (DMPEA) on alpha 1- and alpha 2-adrenoceptors were examined in the isolated rat vas deferens. The active species of DMPEA was the corresponding ethyleniminium ion, which forms in the biophase, since pretreatment of tissues with sodium thiosulphate completely prevented the DMPEA-induced inhibition at alpha 1- and alpha 2-adrenoceptors. DMPEA was approximately 42-fold more potent in inhibiting alpha 2-adrenoceptors than it was in inhibiting alpha 1-adrenoceptors. The antagonism of both receptor types was reversible since washing of the tissues after incubation with DMPEA brought the agonist dose-response curve back to the control value. At alpha 1-adrenoceptors, DMPEA displaced the noradrenaline dose-response curve to the right and concomitantly depressed the maximum response, effects which are consistent with a non-competitive mechanism of action. At alpha 2-adrenoceptors, DMPEA caused a parallel shift of the clonidine or noradrenaline dose-response curve to the right in field-stimulated prostatic portions of the rat vas deferens. The antagonism appeared to be competitive at low concentrations, whereas the shift of the clonidine dose-response curve at higher concentrations became overproportional to the DMPEA concentration. A combination of DMPEA with idazoxan produced a less-than-additive shift of the dose-response curve for clonidine, indicating that these antagonists do not bind to the same site.

Adrenergic alpha-Antagonists↗

PubMed1985

Preparation of 13N-beta-phenethylamine.

Nitrogen-13-labelled beta-phenethylamine[( 13N]PEA) was synthesized by Hofmann rearrangement of [13N]phenylpropionamide prepared from phenylpropionyl chloride and aqueous [13N]ammonia solution. The reaction proceeded rapidly with a fairly good yield. [13N]PEA was isolated using preparative thin-layer chromatography, and organ distribution in mice was studied preliminarily. After i.v. administration of [13N]PEA, high accumulation and long-term retention of the radioactivity were observed in the brain and the heart.

Animals↗

PubMed1984

Unreliability of the rat stomach fundus as a predictor of hallucinogenic activity in substituted phenethylamines.

A series of three isomeric 2,4,5-substituted monoethoxy dimethoxy phenylisopropylamines were compared for their contractile effect in the rat fundus as potential antagonists to the effect of serotonin in the fundus. The three isomers were also evaluated for their discriminative stimulus properties in rats that had been trained to discriminate injections of saline from LSD tartrate (0.08 mg/kg). The drug discrimination studies revealed that the 2,5-dimethoxy-4-ethoxy substitution was most potent in rats, consistent with the reported clinical activity of this isomer in man. By contrast, of the three isomers examined, this was the weakest in eliciting a contraction in the fundus. None of the compounds antagonized serotonin induced contractions, and it was not possible to determine pA2 values. Questions are raised about the determination of pA2 values for partial agonists and it is concluded that the fundus is not a reliable model for prediction of hallucinogenic activity of phenethylamines.

Animals↗

PubMed1977

Characteristics of beta-phenethylamine self-administration by dog.

Phenethylamine (PEA), a biologically active amine found in the brain, maintained intravenous self-administration behavior by dogs previously trained to respond for amphetamine. Systematic changes in the unit dose of PEA (1.5 to 6.0 mg/kg/infusion) were negatively related to the number of infusions (91.3 to 29.5, respectively) per 4hr session. The mean intake of PEA was 165 mg/kg/session. Pretreatment with chlorpromazine (0.5 to 2.0 mg/kg, IV, 30 min prior to the session) produced a dose-dependent increase in the number of self-administered PEA infusions. However, there were no changes in responding for PEA following pretreatment with either the dopaminergic antagonist pimozide (5 to 40 micrograms/kg, IV, 30 min prior to the session) or the adrenergic antagonist phenoxybenzamine (1 to 8 mg/kg, IV, 30 min prior to the session). These data suggest that the reinforcing properties of PEA are not dependent on either a dopaminergic or adrenergic system.

Animals↗

PubMedDate not supplied

The detection, identification and measurement of indole, tryptamine and 2-phenethylamine in putrefying human tissue.

Indole, tryptamine and 2-phenethylamine are putrefactive products which may be found in decaying human tissue. They may be identified by the data given found in decaying human tissue. They may be identified by the data given for infrared and ultraviolet spectrometry, fluorometry, thin layer and gas chromatography and mass spectrometry. Quantitative studies may be made using the gas chromatography method described. The rate of formation is affected by temperature and preservatives and may be prevented if necessary by the use of sodium fluoride. No relationship between the production of these materials (and alcohol) and time since the post-mortem examination could be established. The post-mortem examinations took place within 24 hours of death.

Ethanol↗

PubMed1994

Chiral discrimination of phenethylamines with beta-cyclodextrin and heptakis(2,3-di-O-acetyl)beta-cyclodextrin by capillary electrophoresis and NMR spectroscopy.

The resolution of nine sympathomimetic phenethylamine racemates by beta-cyclodextrin and heptakis(2,3-di-O-acetyl)beta-cyclodextrin has been investigated by capillary electrophoresis and 1H NMR spectroscopy. The NMR and capillary electrophoresis results showed that beta-cyclodextrin probably formed stronger complexes with the amines than did heptakis(2,3-di-O-acetyl)beta-cyclodextrin but was a poorer chiral discrimination agent in both techniques. The addition of heptakis(2,3-di-O-acetyl)beta-cyclodextrin to the capillary electrophoresis buffer gave baseline resolution of enantiomer peaks for seven of the compounds studied while beta-cyclodextrin resolved only three of the racemates.

Cyclodextrins↗

PubMed2005

Chiral cyclopalladated complexes derived from N,N-dimethyl-1-phenethylamine with bridging bis(diphenylphosphine)ferrocene ligand as inhibitors of the cathepsin B activity and as antitumoral agents.

Chiral cyclopalladated complexes derived from N,N-dimethyl-1-phenethylamine and the coordinating ligand 1,1'-bis(diphenylphosphine)ferrocene were synthesized and studied as Cathepsin B inhibitors and antitumoral agents against solid tumors. Our results revealed that the palladium compound [Pd2(C2,N-S(-)dmpa)2(mu-dppf)Cl2] (2) was able to inhibit Cathepsin B activity in a reversible fashion. This palladacycle compound binds to free cathepsin B (E) as well as to the enzyme-substrate complex (ES) with dissociation constants of KH=12+/-1 microM and alphaKH=2.4+/-0.3 microM, respectively. The application of this complex, in Walker tumor-bearing rats, resulted in 90% inhibition of the tumor growth. Subcutaneous inoculations of 10(6) tumoral cells produced solid tumors with a mass of 4.0+/-1.0 g in 12 days Walker tumor-bearing rats. However, when these animals were treated with one dose of the palladacycle compound (2.0 mg/kg), the tumoral mass was reduced to 0.3+/-0.1 g. On the other hand, the same complex (2) did not afford any protection to mice bearing the non-metastatic Ehrlich Ascites tumor treated with doses of 0.5, 5.0, and 30 mg/kg for a period of four, three and one day, respectively, beginning 72 h after tumor inoculation. Toxicological studies using mice treated with one high dose of the complex (2) (100 mg/kg) did not show any alterations in red and white blood cell morphology 14 days after the drug administration. Similar results were obtained with hepatic, kidney, and spleen tissues. The results presented in this work introduce the title cyclopalladated complexes as promising antitumoral drugs with reduced toxicity in experimental studies.

Animals↗

PubMed2005

N-Alkylation of phenethylamine and tryptamine.

A clean and efficient method for the N-alkylation of tryptamine and phenethylamine, employing alcohols as the alkylating agents, has been developed. The reaction proceeds via catalytic electronic activation, involving an iridium catalyst which activates the alcohol by borrowing hydrogen from the substrate, returning it later in the catalytic cycle. Some examples of N-heterocyclisation have been performed employing a diol as the substrate.

Alcohols↗

PubMed2002

Analysis of enantiomers of chiral phenethylamine drugs by capillary gas chromatography/mass spectrometry/flame-ionization detection and pre-column chiral derivatization.

Several important chiral phenethylamine agents such as mexiletine, fenfluramine, amphetamine, methamphetamine and N-n-propylamphetamine show stereoselective disposition in humans and large differences in therapeutic relevance and toxicity. To analyze the enantiomers of chiral amine drugs, stereoselective methods were developed to separate those enantiomers on an achiral capillary gas chromatography by pre-column chiral derivatization with S-(-)-N-(fluoroacyl)-prolyl chloride. The stereoselectivity and sensitivity can be improved by chiral derivatization. The methods established offer enantioselective, simple, flexible and economic approaches for the analysis of chiral amine drug enantiomers in biological fluids. The methods have been used to determine S-(+)-methamphetamine in human forensic samples and to analyze enantiomers of amphetamine and fenfluramine in rat liver microsomes.

Chromatography, Gas↗

PubMed1997

Optimization of a simple method for the chiral separation of phenethylamines of forensic interest based on cyclodextrin complexation capillary electrophoresis and its preliminary application to the analysis of human urine and hair.

Because of the forensic importance of the chiral analysis of amphetamine and other phenethylamines for investigating their synthetic pathways and the metabolic patterns of these compounds, a capillary electrophoresis method has been developed based on the chiral selectivity of beta-cyclodextrin. The influence of different experimental conditions, such as cyclodextrin nature and concentration, voltage, temperature and buffer concentration and pH, on analytical performance has been studied. The optimized analytical conditions are: capillary: bare fused silica, 50 microns I.D., 40 cm effective length; buffer: 150 mM phosphate pH = 2.5, 15 mM beta-cyclodextrin; voltage: 10 kV; temperature: 17.5 degrees C; detection: UV absorption at 200 nm wavelength. Under these conditions, amphetamine, methamphetamine and ephedrine have been easily separated, with baseline resolution of the respective enantiomers. Sensitivity was better than 300 ng per ml. The average precision of migration times of the three analytes was good with RSD = 0.45% and 0.58% in intra-day and day-to-day tests, respectively. Reproducibility of peak heights was also good, with RSD = 2.51% and 3.14% in intra-day and day-to-day tests, respectively. The preliminary analysis of amphetamine in human urine and hair samples, subjected to a simple work-up procedure based on liquid-liquid extraction, showed clean blank electropherograms, excellent chiral resolution and sensitivity, suitable for the analysis of real samples from amphetamine users.

Amphetamine↗

PubMed1980

Comparison of biological effects of N-alkylated congeners of beta-phenethylamine derived from 2-aminotetralin, 2-aminoindan, and 6-aminobenzocycloheptene.

Three series of bicyclic, semirigid congeners of beta-phenethylamine have been prepared for evaluation of the effect of ring size (and of concomitant conformational variation) on biological activity in a variety of assays for adrenergic and dopaminergic actions. Pharmacologic activity was associated with 2-aminotetralin and 2-aminoindan derivateves, but was not found with 6-aminobenzocycloheptene derivatives. Noteworthy is the ability of several aminotetralins and aminoindans to increase the hot-plate reaction time without eliciting dopaminergic effects. This action was not blocked by pretreatment with naloxone.

Amines↗

PubMed1975

Correlation of psychotomimetic activity of phenethylamines and amphetamines with 1-octanol-water partition coefficients.

In an attempt to relate the hallucinogenic potencies in man of some biologically important amphetamines and phenethylamines, the 1-octanol-water partition coefficients for 11 amphetamines were determined. Using these values and published Hansch pi constants, the log P for 17 additional amines was estimated. It was found that lipophilicity, as measured by the log of the partition coefficient, may be a significant determinant of the level of hallucinogenic potency. The study also suggests that an ideal log P value for psychotomimetric activity in man may be from 2.89 to 3.72.

Amphetamines↗